VM: Remove "clear_page_dirty()" and "test_clear_page_dirty()" functions
[linux-2.6.git] / include / linux / page-flags.h
1 /*
2  * Macros for manipulating and testing page->flags
3  */
4
5 #ifndef PAGE_FLAGS_H
6 #define PAGE_FLAGS_H
7
8 #include <linux/types.h>
9
10 /*
11  * Various page->flags bits:
12  *
13  * PG_reserved is set for special pages, which can never be swapped out. Some
14  * of them might not even exist (eg empty_bad_page)...
15  *
16  * The PG_private bitflag is set on pagecache pages if they contain filesystem
17  * specific data (which is normally at page->private). It can be used by
18  * private allocations for its own usage.
19  *
20  * During initiation of disk I/O, PG_locked is set. This bit is set before I/O
21  * and cleared when writeback _starts_ or when read _completes_. PG_writeback
22  * is set before writeback starts and cleared when it finishes.
23  *
24  * PG_locked also pins a page in pagecache, and blocks truncation of the file
25  * while it is held.
26  *
27  * page_waitqueue(page) is a wait queue of all tasks waiting for the page
28  * to become unlocked.
29  *
30  * PG_uptodate tells whether the page's contents is valid.  When a read
31  * completes, the page becomes uptodate, unless a disk I/O error happened.
32  *
33  * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
34  * file-backed pagecache (see mm/vmscan.c).
35  *
36  * PG_error is set to indicate that an I/O error occurred on this page.
37  *
38  * PG_arch_1 is an architecture specific page state bit.  The generic code
39  * guarantees that this bit is cleared for a page when it first is entered into
40  * the page cache.
41  *
42  * PG_highmem pages are not permanently mapped into the kernel virtual address
43  * space, they need to be kmapped separately for doing IO on the pages.  The
44  * struct page (these bits with information) are always mapped into kernel
45  * address space...
46  *
47  * PG_buddy is set to indicate that the page is free and in the buddy system
48  * (see mm/page_alloc.c).
49  *
50  */
51
52 /*
53  * Don't use the *_dontuse flags.  Use the macros.  Otherwise you'll break
54  * locked- and dirty-page accounting.
55  *
56  * The page flags field is split into two parts, the main flags area
57  * which extends from the low bits upwards, and the fields area which
58  * extends from the high bits downwards.
59  *
60  *  | FIELD | ... | FLAGS |
61  *  N-1     ^             0
62  *          (N-FLAGS_RESERVED)
63  *
64  * The fields area is reserved for fields mapping zone, node and SPARSEMEM
65  * section.  The boundry between these two areas is defined by
66  * FLAGS_RESERVED which defines the width of the fields section
67  * (see linux/mmzone.h).  New flags must _not_ overlap with this area.
68  */
69 #define PG_locked                0      /* Page is locked. Don't touch. */
70 #define PG_error                 1
71 #define PG_referenced            2
72 #define PG_uptodate              3
73
74 #define PG_dirty                 4
75 #define PG_lru                   5
76 #define PG_active                6
77 #define PG_slab                  7      /* slab debug (Suparna wants this) */
78
79 #define PG_checked               8      /* kill me in 2.5.<early>. */
80 #define PG_arch_1                9
81 #define PG_reserved             10
82 #define PG_private              11      /* If pagecache, has fs-private data */
83
84 #define PG_writeback            12      /* Page is under writeback */
85 #define PG_nosave               13      /* Used for system suspend/resume */
86 #define PG_compound             14      /* Part of a compound page */
87 #define PG_swapcache            15      /* Swap page: swp_entry_t in private */
88
89 #define PG_mappedtodisk         16      /* Has blocks allocated on-disk */
90 #define PG_reclaim              17      /* To be reclaimed asap */
91 #define PG_nosave_free          18      /* Used for system suspend/resume */
92 #define PG_buddy                19      /* Page is free, on buddy lists */
93
94
95 #if (BITS_PER_LONG > 32)
96 /*
97  * 64-bit-only flags build down from bit 31
98  *
99  * 32 bit  -------------------------------| FIELDS |       FLAGS         |
100  * 64 bit  |           FIELDS             | ??????         FLAGS         |
101  *         63                            32                              0
102  */
103 #define PG_uncached             31      /* Page has been mapped as uncached */
104 #endif
105
106 /*
107  * Manipulation of page state flags
108  */
109 #define PageLocked(page)                \
110                 test_bit(PG_locked, &(page)->flags)
111 #define SetPageLocked(page)             \
112                 set_bit(PG_locked, &(page)->flags)
113 #define TestSetPageLocked(page)         \
114                 test_and_set_bit(PG_locked, &(page)->flags)
115 #define ClearPageLocked(page)           \
116                 clear_bit(PG_locked, &(page)->flags)
117 #define TestClearPageLocked(page)       \
118                 test_and_clear_bit(PG_locked, &(page)->flags)
119
120 #define PageError(page)         test_bit(PG_error, &(page)->flags)
121 #define SetPageError(page)      set_bit(PG_error, &(page)->flags)
122 #define ClearPageError(page)    clear_bit(PG_error, &(page)->flags)
123
124 #define PageReferenced(page)    test_bit(PG_referenced, &(page)->flags)
125 #define SetPageReferenced(page) set_bit(PG_referenced, &(page)->flags)
126 #define ClearPageReferenced(page)       clear_bit(PG_referenced, &(page)->flags)
127 #define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags)
128
129 #define PageUptodate(page)      test_bit(PG_uptodate, &(page)->flags)
130 #ifdef CONFIG_S390
131 static inline void SetPageUptodate(struct page *page)
132 {
133         if (!test_and_set_bit(PG_uptodate, &page->flags))
134                 page_test_and_clear_dirty(page);
135 }
136 #else
137 #define SetPageUptodate(page)   set_bit(PG_uptodate, &(page)->flags)
138 #endif
139 #define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags)
140
141 #define PageDirty(page)         test_bit(PG_dirty, &(page)->flags)
142 #define SetPageDirty(page)      set_bit(PG_dirty, &(page)->flags)
143 #define TestSetPageDirty(page)  test_and_set_bit(PG_dirty, &(page)->flags)
144 #define ClearPageDirty(page)    clear_bit(PG_dirty, &(page)->flags)
145 #define __ClearPageDirty(page)  __clear_bit(PG_dirty, &(page)->flags)
146 #define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags)
147
148 #define PageLRU(page)           test_bit(PG_lru, &(page)->flags)
149 #define SetPageLRU(page)        set_bit(PG_lru, &(page)->flags)
150 #define ClearPageLRU(page)      clear_bit(PG_lru, &(page)->flags)
151 #define __ClearPageLRU(page)    __clear_bit(PG_lru, &(page)->flags)
152
153 #define PageActive(page)        test_bit(PG_active, &(page)->flags)
154 #define SetPageActive(page)     set_bit(PG_active, &(page)->flags)
155 #define ClearPageActive(page)   clear_bit(PG_active, &(page)->flags)
156 #define __ClearPageActive(page) __clear_bit(PG_active, &(page)->flags)
157
158 #define PageSlab(page)          test_bit(PG_slab, &(page)->flags)
159 #define __SetPageSlab(page)     __set_bit(PG_slab, &(page)->flags)
160 #define __ClearPageSlab(page)   __clear_bit(PG_slab, &(page)->flags)
161
162 #ifdef CONFIG_HIGHMEM
163 #define PageHighMem(page)       is_highmem(page_zone(page))
164 #else
165 #define PageHighMem(page)       0 /* needed to optimize away at compile time */
166 #endif
167
168 #define PageChecked(page)       test_bit(PG_checked, &(page)->flags)
169 #define SetPageChecked(page)    set_bit(PG_checked, &(page)->flags)
170 #define ClearPageChecked(page)  clear_bit(PG_checked, &(page)->flags)
171
172 #define PageReserved(page)      test_bit(PG_reserved, &(page)->flags)
173 #define SetPageReserved(page)   set_bit(PG_reserved, &(page)->flags)
174 #define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags)
175 #define __ClearPageReserved(page)       __clear_bit(PG_reserved, &(page)->flags)
176
177 #define SetPagePrivate(page)    set_bit(PG_private, &(page)->flags)
178 #define ClearPagePrivate(page)  clear_bit(PG_private, &(page)->flags)
179 #define PagePrivate(page)       test_bit(PG_private, &(page)->flags)
180 #define __SetPagePrivate(page)  __set_bit(PG_private, &(page)->flags)
181 #define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags)
182
183 #define PageWriteback(page)     test_bit(PG_writeback, &(page)->flags)
184 #define SetPageWriteback(page)                                          \
185         do {                                                            \
186                 if (!test_and_set_bit(PG_writeback,                     \
187                                 &(page)->flags))                        \
188                         inc_zone_page_state(page, NR_WRITEBACK);        \
189         } while (0)
190 #define TestSetPageWriteback(page)                                      \
191         ({                                                              \
192                 int ret;                                                \
193                 ret = test_and_set_bit(PG_writeback,                    \
194                                         &(page)->flags);                \
195                 if (!ret)                                               \
196                         inc_zone_page_state(page, NR_WRITEBACK);        \
197                 ret;                                                    \
198         })
199 #define ClearPageWriteback(page)                                        \
200         do {                                                            \
201                 if (test_and_clear_bit(PG_writeback,                    \
202                                 &(page)->flags))                        \
203                         dec_zone_page_state(page, NR_WRITEBACK);        \
204         } while (0)
205 #define TestClearPageWriteback(page)                                    \
206         ({                                                              \
207                 int ret;                                                \
208                 ret = test_and_clear_bit(PG_writeback,                  \
209                                 &(page)->flags);                        \
210                 if (ret)                                                \
211                         dec_zone_page_state(page, NR_WRITEBACK);        \
212                 ret;                                                    \
213         })
214
215 #define PageNosave(page)        test_bit(PG_nosave, &(page)->flags)
216 #define SetPageNosave(page)     set_bit(PG_nosave, &(page)->flags)
217 #define TestSetPageNosave(page) test_and_set_bit(PG_nosave, &(page)->flags)
218 #define ClearPageNosave(page)           clear_bit(PG_nosave, &(page)->flags)
219 #define TestClearPageNosave(page)       test_and_clear_bit(PG_nosave, &(page)->flags)
220
221 #define PageNosaveFree(page)    test_bit(PG_nosave_free, &(page)->flags)
222 #define SetPageNosaveFree(page) set_bit(PG_nosave_free, &(page)->flags)
223 #define ClearPageNosaveFree(page)               clear_bit(PG_nosave_free, &(page)->flags)
224
225 #define PageBuddy(page)         test_bit(PG_buddy, &(page)->flags)
226 #define __SetPageBuddy(page)    __set_bit(PG_buddy, &(page)->flags)
227 #define __ClearPageBuddy(page)  __clear_bit(PG_buddy, &(page)->flags)
228
229 #define PageMappedToDisk(page)  test_bit(PG_mappedtodisk, &(page)->flags)
230 #define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags)
231 #define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags)
232
233 #define PageReclaim(page)       test_bit(PG_reclaim, &(page)->flags)
234 #define SetPageReclaim(page)    set_bit(PG_reclaim, &(page)->flags)
235 #define ClearPageReclaim(page)  clear_bit(PG_reclaim, &(page)->flags)
236 #define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags)
237
238 #define PageCompound(page)      test_bit(PG_compound, &(page)->flags)
239 #define __SetPageCompound(page) __set_bit(PG_compound, &(page)->flags)
240 #define __ClearPageCompound(page) __clear_bit(PG_compound, &(page)->flags)
241
242 #ifdef CONFIG_SWAP
243 #define PageSwapCache(page)     test_bit(PG_swapcache, &(page)->flags)
244 #define SetPageSwapCache(page)  set_bit(PG_swapcache, &(page)->flags)
245 #define ClearPageSwapCache(page) clear_bit(PG_swapcache, &(page)->flags)
246 #else
247 #define PageSwapCache(page)     0
248 #endif
249
250 #define PageUncached(page)      test_bit(PG_uncached, &(page)->flags)
251 #define SetPageUncached(page)   set_bit(PG_uncached, &(page)->flags)
252 #define ClearPageUncached(page) clear_bit(PG_uncached, &(page)->flags)
253
254 struct page;    /* forward declaration */
255
256 extern void cancel_dirty_page(struct page *page, unsigned int account_size);
257
258 int test_clear_page_writeback(struct page *page);
259 int test_set_page_writeback(struct page *page);
260
261 static inline void set_page_writeback(struct page *page)
262 {
263         test_set_page_writeback(page);
264 }
265
266 #endif  /* PAGE_FLAGS_H */