source: trunk/packages/xen-3.1/xen-3.1/linux-2.6-xen-sparse/include/linux/page-flags.h @ 34

Last change on this file since 34 was 34, checked in by hartmans, 17 years ago

Add xen and xen-common
File size: 10.6 KB
RevLine 
[34]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 if page->private contains a valid value.
17 *
18 * During disk I/O, PG_locked is used. This bit is set before I/O and
19 * reset when I/O completes. page_waitqueue(page) is a wait queue of all tasks
20 * waiting for the I/O on this page to complete.
21 *
22 * PG_uptodate tells whether the page's contents is valid.  When a read
23 * completes, the page becomes uptodate, unless a disk I/O error happened.
24 *
25 * For choosing which pages to swap out, inode pages carry a PG_referenced bit,
26 * which is set any time the system accesses that page through the (mapping,
27 * index) hash table.  This referenced bit, together with the referenced bit
28 * in the page tables, is used to manipulate page->age and move the page across
29 * the active, inactive_dirty and inactive_clean lists.
30 *
31 * Note that the referenced bit, the page->lru list_head and the active,
32 * inactive_dirty and inactive_clean lists are protected by the
33 * zone->lru_lock, and *NOT* by the usual PG_locked bit!
34 *
35 * PG_error is set to indicate that an I/O error occurred on this page.
36 *
37 * PG_arch_1 is an architecture specific page state bit.  The generic code
38 * guarantees that this bit is cleared for a page when it first is entered into
39 * the page cache.
40 *
41 * PG_highmem pages are not permanently mapped into the kernel virtual address
42 * space, they need to be kmapped separately for doing IO on the pages.  The
43 * struct page (these bits with information) are always mapped into kernel
44 * address space...
45 */
46
47/*
48 * Don't use the *_dontuse flags.  Use the macros.  Otherwise you'll break
49 * locked- and dirty-page accounting.
50 *
51 * The page flags field is split into two parts, the main flags area
52 * which extends from the low bits upwards, and the fields area which
53 * extends from the high bits downwards.
54 *
55 *  | FIELD | ... | FLAGS |
56 *  N-1     ^             0
57 *          (N-FLAGS_RESERVED)
58 *
59 * The fields area is reserved for fields mapping zone, node and SPARSEMEM
60 * section.  The boundry between these two areas is defined by
61 * FLAGS_RESERVED which defines the width of the fields section
62 * (see linux/mmzone.h).  New flags must _not_ overlap with this area.
63 */
64#define PG_locked                0      /* Page is locked. Don't touch. */
65#define PG_error                 1
66#define PG_referenced            2
67#define PG_uptodate              3
68
69#define PG_dirty                 4
70#define PG_lru                   5
71#define PG_active                6
72#define PG_slab                  7      /* slab debug (Suparna wants this) */
73
74#define PG_checked               8      /* kill me in 2.5.<early>. */
75#define PG_arch_1                9
76#define PG_reserved             10
77#define PG_private              11      /* Has something at ->private */
78
79#define PG_writeback            12      /* Page is under writeback */
80#define PG_nosave               13      /* Used for system suspend/resume */
81#define PG_compound             14      /* Part of a compound page */
82#define PG_swapcache            15      /* Swap page: swp_entry_t in private */
83
84#define PG_mappedtodisk         16      /* Has blocks allocated on-disk */
85#define PG_reclaim              17      /* To be reclaimed asap */
86#define PG_nosave_free          18      /* Free, should not be written */
87#define PG_buddy                19      /* Page is free, on buddy lists */
88
89
90#if (BITS_PER_LONG > 32)
91/*
92 * 64-bit-only flags build down from bit 31
93 *
94 * 32 bit  -------------------------------| FIELDS |       FLAGS         |
95 * 64 bit  |           FIELDS             | ??????         FLAGS         |
96 *         63                            32                              0
97 */
98#define PG_uncached             31      /* Page has been mapped as uncached */
99#endif
100
101#define PG_foreign              20      /* Page is owned by foreign allocator. */
102
103/*
104 * Manipulation of page state flags
105 */
106#define PageLocked(page)                \
107                test_bit(PG_locked, &(page)->flags)
108#define SetPageLocked(page)             \
109                set_bit(PG_locked, &(page)->flags)
110#define TestSetPageLocked(page)         \
111                test_and_set_bit(PG_locked, &(page)->flags)
112#define ClearPageLocked(page)           \
113                clear_bit(PG_locked, &(page)->flags)
114#define TestClearPageLocked(page)       \
115                test_and_clear_bit(PG_locked, &(page)->flags)
116
117#define PageError(page)         test_bit(PG_error, &(page)->flags)
118#define SetPageError(page)      set_bit(PG_error, &(page)->flags)
119#define ClearPageError(page)    clear_bit(PG_error, &(page)->flags)
120
121#define PageReferenced(page)    test_bit(PG_referenced, &(page)->flags)
122#define SetPageReferenced(page) set_bit(PG_referenced, &(page)->flags)
123#define ClearPageReferenced(page)       clear_bit(PG_referenced, &(page)->flags)
124#define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags)
125
126#define PageUptodate(page)      test_bit(PG_uptodate, &(page)->flags)
127#ifdef CONFIG_S390
128#define SetPageUptodate(_page) \
129        do {                                                                  \
130                struct page *__page = (_page);                                \
131                if (!test_and_set_bit(PG_uptodate, &__page->flags))           \
132                        page_test_and_clear_dirty(_page);                     \
133        } while (0)
134#else
135#define SetPageUptodate(page)   set_bit(PG_uptodate, &(page)->flags)
136#endif
137#define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags)
138
139#define PageDirty(page)         test_bit(PG_dirty, &(page)->flags)
140#define SetPageDirty(page)      set_bit(PG_dirty, &(page)->flags)
141#define TestSetPageDirty(page)  test_and_set_bit(PG_dirty, &(page)->flags)
142#define ClearPageDirty(page)    clear_bit(PG_dirty, &(page)->flags)
143#define __ClearPageDirty(page)  __clear_bit(PG_dirty, &(page)->flags)
144#define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags)
145
146#define PageLRU(page)           test_bit(PG_lru, &(page)->flags)
147#define SetPageLRU(page)        set_bit(PG_lru, &(page)->flags)
148#define ClearPageLRU(page)      clear_bit(PG_lru, &(page)->flags)
149#define __ClearPageLRU(page)    __clear_bit(PG_lru, &(page)->flags)
150
151#define PageActive(page)        test_bit(PG_active, &(page)->flags)
152#define SetPageActive(page)     set_bit(PG_active, &(page)->flags)
153#define ClearPageActive(page)   clear_bit(PG_active, &(page)->flags)
154#define __ClearPageActive(page) __clear_bit(PG_active, &(page)->flags)
155
156#define PageSlab(page)          test_bit(PG_slab, &(page)->flags)
157#define __SetPageSlab(page)     __set_bit(PG_slab, &(page)->flags)
158#define __ClearPageSlab(page)   __clear_bit(PG_slab, &(page)->flags)
159
160#ifdef CONFIG_HIGHMEM
161#define PageHighMem(page)       is_highmem(page_zone(page))
162#else
163#define PageHighMem(page)       0 /* needed to optimize away at compile time */
164#endif
165
166#define PageChecked(page)       test_bit(PG_checked, &(page)->flags)
167#define SetPageChecked(page)    set_bit(PG_checked, &(page)->flags)
168#define ClearPageChecked(page)  clear_bit(PG_checked, &(page)->flags)
169
170#define PageReserved(page)      test_bit(PG_reserved, &(page)->flags)
171#define SetPageReserved(page)   set_bit(PG_reserved, &(page)->flags)
172#define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags)
173#define __ClearPageReserved(page)       __clear_bit(PG_reserved, &(page)->flags)
174
175#define SetPagePrivate(page)    set_bit(PG_private, &(page)->flags)
176#define ClearPagePrivate(page)  clear_bit(PG_private, &(page)->flags)
177#define PagePrivate(page)       test_bit(PG_private, &(page)->flags)
178#define __SetPagePrivate(page)  __set_bit(PG_private, &(page)->flags)
179#define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags)
180
181#define PageWriteback(page)     test_bit(PG_writeback, &(page)->flags)
182#define SetPageWriteback(page)                                          \
183        do {                                                            \
184                if (!test_and_set_bit(PG_writeback,                     \
185                                &(page)->flags))                        \
186                        inc_zone_page_state(page, NR_WRITEBACK);        \
187        } while (0)
188#define TestSetPageWriteback(page)                                      \
189        ({                                                              \
190                int ret;                                                \
191                ret = test_and_set_bit(PG_writeback,                    \
192                                        &(page)->flags);                \
193                if (!ret)                                               \
194                        inc_zone_page_state(page, NR_WRITEBACK);        \
195                ret;                                                    \
196        })
197#define ClearPageWriteback(page)                                        \
198        do {                                                            \
199                if (test_and_clear_bit(PG_writeback,                    \
200                                &(page)->flags))                        \
201                        dec_zone_page_state(page, NR_WRITEBACK);        \
202        } while (0)
203#define TestClearPageWriteback(page)                                    \
204        ({                                                              \
205                int ret;                                                \
206                ret = test_and_clear_bit(PG_writeback,                  \
207                                &(page)->flags);                        \
208                if (ret)                                                \
209                        dec_zone_page_state(page, NR_WRITEBACK);        \
210                ret;                                                    \
211        })
212
213#define PageNosave(page)        test_bit(PG_nosave, &(page)->flags)
214#define SetPageNosave(page)     set_bit(PG_nosave, &(page)->flags)
215#define TestSetPageNosave(page) test_and_set_bit(PG_nosave, &(page)->flags)
216#define ClearPageNosave(page)           clear_bit(PG_nosave, &(page)->flags)
217#define TestClearPageNosave(page)       test_and_clear_bit(PG_nosave, &(page)->flags)
218
219#define PageNosaveFree(page)    test_bit(PG_nosave_free, &(page)->flags)
220#define SetPageNosaveFree(page) set_bit(PG_nosave_free, &(page)->flags)
221#define ClearPageNosaveFree(page)               clear_bit(PG_nosave_free, &(page)->flags)
222
223#define PageBuddy(page)         test_bit(PG_buddy, &(page)->flags)
224#define __SetPageBuddy(page)    __set_bit(PG_buddy, &(page)->flags)
225#define __ClearPageBuddy(page)  __clear_bit(PG_buddy, &(page)->flags)
226
227#define PageMappedToDisk(page)  test_bit(PG_mappedtodisk, &(page)->flags)
228#define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags)
229#define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags)
230
231#define PageReclaim(page)       test_bit(PG_reclaim, &(page)->flags)
232#define SetPageReclaim(page)    set_bit(PG_reclaim, &(page)->flags)
233#define ClearPageReclaim(page)  clear_bit(PG_reclaim, &(page)->flags)
234#define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags)
235
236#define PageCompound(page)      test_bit(PG_compound, &(page)->flags)
237#define __SetPageCompound(page) __set_bit(PG_compound, &(page)->flags)
238#define __ClearPageCompound(page) __clear_bit(PG_compound, &(page)->flags)
239
240#ifdef CONFIG_SWAP
241#define PageSwapCache(page)     test_bit(PG_swapcache, &(page)->flags)
242#define SetPageSwapCache(page)  set_bit(PG_swapcache, &(page)->flags)
243#define ClearPageSwapCache(page) clear_bit(PG_swapcache, &(page)->flags)
244#else
245#define PageSwapCache(page)     0
246#endif
247
248#define PageUncached(page)      test_bit(PG_uncached, &(page)->flags)
249#define SetPageUncached(page)   set_bit(PG_uncached, &(page)->flags)
250#define ClearPageUncached(page) clear_bit(PG_uncached, &(page)->flags)
251
252#define PageForeign(page)       test_bit(PG_foreign, &(page)->flags)
253#define SetPageForeign(page, dtor) do {         \
254        set_bit(PG_foreign, &(page)->flags);    \
255        (page)->index = (long)(dtor);           \
256} while (0)
257#define ClearPageForeign(page) do {             \
258        clear_bit(PG_foreign, &(page)->flags);  \
259        (page)->index = 0;                      \
260} while (0)
261#define PageForeignDestructor(page)             \
262        ( (void (*) (struct page *)) (page)->index )(page)
263
264struct page;    /* forward declaration */
265
266int test_clear_page_dirty(struct page *page);
267int test_clear_page_writeback(struct page *page);
268int test_set_page_writeback(struct page *page);
269
270static inline void clear_page_dirty(struct page *page)
271{
272        test_clear_page_dirty(page);
273}
274
275static inline void set_page_writeback(struct page *page)
276{
277        test_set_page_writeback(page);
278}
279
280#endif  /* PAGE_FLAGS_H */
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