2 * Macros for manipulating and testing page->flags
8 #include <linux/percpu.h>
9 #include <linux/cache.h>
10 #include <asm/pgtable.h>
13 * Various page->flags bits:
15 * PG_reserved is set for special pages, which can never be swapped out. Some
16 * of them might not even exist (eg empty_bad_page)...
18 * The PG_private bitflag is set if page->private contains a valid value.
20 * During disk I/O, PG_locked is used. This bit is set before I/O and
21 * reset when I/O completes. page_waitqueue(page) is a wait queue of all tasks
22 * waiting for the I/O on this page to complete.
24 * PG_uptodate tells whether the page's contents is valid. When a read
25 * completes, the page becomes uptodate, unless a disk I/O error happened.
27 * For choosing which pages to swap out, inode pages carry a PG_referenced bit,
28 * which is set any time the system accesses that page through the (mapping,
29 * index) hash table. This referenced bit, together with the referenced bit
30 * in the page tables, is used to manipulate page->age and move the page across
31 * the active, inactive_dirty and inactive_clean lists.
33 * Note that the referenced bit, the page->lru list_head and the active,
34 * inactive_dirty and inactive_clean lists are protected by the
35 * zone->lru_lock, and *NOT* by the usual PG_locked bit!
37 * PG_error is set to indicate that an I/O error occurred on this page.
39 * PG_arch_1 is an architecture specific page state bit. The generic code
40 * guarantees that this bit is cleared for a page when it first is entered into
43 * PG_highmem pages are not permanently mapped into the kernel virtual address
44 * space, they need to be kmapped separately for doing IO on the pages. The
45 * struct page (these bits with information) are always mapped into kernel
50 * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
51 * locked- and dirty-page accounting. The top eight bits of page->flags are
52 * used for page->zone, so putting flag bits there doesn't work.
54 #define PG_locked 0 /* Page is locked. Don't touch. */
56 #define PG_referenced 2
62 #define PG_slab 7 /* slab debug (Suparna wants this) */
64 #define PG_checked 8 /* kill me in 2.5.<early>. */
66 #define PG_reserved 10
67 #define PG_private 11 /* Has something at ->private */
69 #define PG_writeback 12 /* Page is under writeback */
70 #define PG_nosave 13 /* Used for system suspend/resume */
71 #define PG_compound 14 /* Part of a compound page */
72 #define PG_swapcache 15 /* Swap page: swp_entry_t in private */
74 #define PG_mappedtodisk 16 /* Has blocks allocated on-disk */
75 #define PG_reclaim 17 /* To be reclaimed asap */
76 #define PG_nosave_free 18 /* Free, should not be written */
77 #define PG_buddy 19 /* Page is free, on buddy lists */
79 #define PG_uncached 20 /* Page has been mapped as uncached */
82 * Global page accounting. One instance per CPU. Only unsigned longs are
85 * - Fields can be modified with xxx_page_state and xxx_page_state_zone at
86 * any time safely (which protects the instance from modification by
88 * - The __xxx_page_state variants can be used safely when interrupts are
90 * - The __xxx_page_state variants can be used if the field is only
91 * modified from process context, or only modified from interrupt context.
92 * In this case, the field should be commented here.
95 unsigned long nr_dirty; /* Dirty writeable pages */
96 unsigned long nr_writeback; /* Pages under writeback */
97 unsigned long nr_unstable; /* NFS unstable pages */
98 unsigned long nr_page_table_pages;/* Pages used for pagetables */
99 unsigned long nr_mapped; /* mapped into pagetables.
100 * only modified from process context */
101 unsigned long nr_slab; /* In slab */
102 #define GET_PAGE_STATE_LAST nr_slab
105 * The below are zeroed by get_page_state(). Use get_full_page_state()
106 * to add up all these.
108 unsigned long pgpgin; /* Disk reads */
109 unsigned long pgpgout; /* Disk writes */
110 unsigned long pswpin; /* swap reads */
111 unsigned long pswpout; /* swap writes */
113 unsigned long pgalloc_high; /* page allocations */
114 unsigned long pgalloc_normal;
115 unsigned long pgalloc_dma32;
116 unsigned long pgalloc_dma;
118 unsigned long pgfree; /* page freeings */
119 unsigned long pgactivate; /* pages moved inactive->active */
120 unsigned long pgdeactivate; /* pages moved active->inactive */
122 unsigned long pgfault; /* faults (major+minor) */
123 unsigned long pgmajfault; /* faults (major only) */
125 unsigned long pgrefill_high; /* inspected in refill_inactive_zone */
126 unsigned long pgrefill_normal;
127 unsigned long pgrefill_dma32;
128 unsigned long pgrefill_dma;
130 unsigned long pgsteal_high; /* total highmem pages reclaimed */
131 unsigned long pgsteal_normal;
132 unsigned long pgsteal_dma32;
133 unsigned long pgsteal_dma;
135 unsigned long pgscan_kswapd_high;/* total highmem pages scanned */
136 unsigned long pgscan_kswapd_normal;
137 unsigned long pgscan_kswapd_dma32;
138 unsigned long pgscan_kswapd_dma;
140 unsigned long pgscan_direct_high;/* total highmem pages scanned */
141 unsigned long pgscan_direct_normal;
142 unsigned long pgscan_direct_dma32;
143 unsigned long pgscan_direct_dma;
145 unsigned long pginodesteal; /* pages reclaimed via inode freeing */
146 unsigned long slabs_scanned; /* slab objects scanned */
147 unsigned long kswapd_steal; /* pages reclaimed by kswapd */
148 unsigned long kswapd_inodesteal;/* reclaimed via kswapd inode freeing */
149 unsigned long pageoutrun; /* kswapd's calls to page reclaim */
150 unsigned long allocstall; /* direct reclaim calls */
152 unsigned long pgrotated; /* pages rotated to tail of the LRU */
153 unsigned long nr_bounce; /* pages for bounce buffers */
156 extern void get_page_state(struct page_state *ret);
157 extern void get_page_state_node(struct page_state *ret, int node);
158 extern void get_full_page_state(struct page_state *ret);
159 extern unsigned long read_page_state_offset(unsigned long offset);
160 extern void mod_page_state_offset(unsigned long offset, unsigned long delta);
161 extern void __mod_page_state_offset(unsigned long offset, unsigned long delta);
163 #define read_page_state(member) \
164 read_page_state_offset(offsetof(struct page_state, member))
166 #define mod_page_state(member, delta) \
167 mod_page_state_offset(offsetof(struct page_state, member), (delta))
169 #define __mod_page_state(member, delta) \
170 __mod_page_state_offset(offsetof(struct page_state, member), (delta))
172 #define inc_page_state(member) mod_page_state(member, 1UL)
173 #define dec_page_state(member) mod_page_state(member, 0UL - 1)
174 #define add_page_state(member,delta) mod_page_state(member, (delta))
175 #define sub_page_state(member,delta) mod_page_state(member, 0UL - (delta))
177 #define __inc_page_state(member) __mod_page_state(member, 1UL)
178 #define __dec_page_state(member) __mod_page_state(member, 0UL - 1)
179 #define __add_page_state(member,delta) __mod_page_state(member, (delta))
180 #define __sub_page_state(member,delta) __mod_page_state(member, 0UL - (delta))
182 #define page_state(member) (*__page_state(offsetof(struct page_state, member)))
184 #define state_zone_offset(zone, member) \
187 if (is_highmem(zone)) \
188 offset = offsetof(struct page_state, member##_high); \
189 else if (is_normal(zone)) \
190 offset = offsetof(struct page_state, member##_normal); \
191 else if (is_dma32(zone)) \
192 offset = offsetof(struct page_state, member##_dma32); \
194 offset = offsetof(struct page_state, member##_dma); \
198 #define __mod_page_state_zone(zone, member, delta) \
200 __mod_page_state_offset(state_zone_offset(zone, member), (delta)); \
203 #define mod_page_state_zone(zone, member, delta) \
205 mod_page_state_offset(state_zone_offset(zone, member), (delta)); \
209 * Manipulation of page state flags
211 #define PageLocked(page) \
212 test_bit(PG_locked, &(page)->flags)
213 #define SetPageLocked(page) \
214 set_bit(PG_locked, &(page)->flags)
215 #define TestSetPageLocked(page) \
216 test_and_set_bit(PG_locked, &(page)->flags)
217 #define ClearPageLocked(page) \
218 clear_bit(PG_locked, &(page)->flags)
219 #define TestClearPageLocked(page) \
220 test_and_clear_bit(PG_locked, &(page)->flags)
222 #define PageError(page) test_bit(PG_error, &(page)->flags)
223 #define SetPageError(page) set_bit(PG_error, &(page)->flags)
224 #define ClearPageError(page) clear_bit(PG_error, &(page)->flags)
226 #define PageReferenced(page) test_bit(PG_referenced, &(page)->flags)
227 #define SetPageReferenced(page) set_bit(PG_referenced, &(page)->flags)
228 #define ClearPageReferenced(page) clear_bit(PG_referenced, &(page)->flags)
229 #define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags)
231 #define PageUptodate(page) test_bit(PG_uptodate, &(page)->flags)
232 #ifndef SetPageUptodate
233 #define SetPageUptodate(page) set_bit(PG_uptodate, &(page)->flags)
235 #define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags)
237 #define PageDirty(page) test_bit(PG_dirty, &(page)->flags)
238 #define SetPageDirty(page) set_bit(PG_dirty, &(page)->flags)
239 #define TestSetPageDirty(page) test_and_set_bit(PG_dirty, &(page)->flags)
240 #define ClearPageDirty(page) clear_bit(PG_dirty, &(page)->flags)
241 #define __ClearPageDirty(page) __clear_bit(PG_dirty, &(page)->flags)
242 #define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags)
244 #define SetPageLRU(page) set_bit(PG_lru, &(page)->flags)
245 #define PageLRU(page) test_bit(PG_lru, &(page)->flags)
246 #define TestSetPageLRU(page) test_and_set_bit(PG_lru, &(page)->flags)
247 #define TestClearPageLRU(page) test_and_clear_bit(PG_lru, &(page)->flags)
249 #define PageActive(page) test_bit(PG_active, &(page)->flags)
250 #define SetPageActive(page) set_bit(PG_active, &(page)->flags)
251 #define ClearPageActive(page) clear_bit(PG_active, &(page)->flags)
252 #define TestClearPageActive(page) test_and_clear_bit(PG_active, &(page)->flags)
253 #define TestSetPageActive(page) test_and_set_bit(PG_active, &(page)->flags)
255 #define PageSlab(page) test_bit(PG_slab, &(page)->flags)
256 #define SetPageSlab(page) set_bit(PG_slab, &(page)->flags)
257 #define ClearPageSlab(page) clear_bit(PG_slab, &(page)->flags)
258 #define TestClearPageSlab(page) test_and_clear_bit(PG_slab, &(page)->flags)
259 #define TestSetPageSlab(page) test_and_set_bit(PG_slab, &(page)->flags)
261 #ifdef CONFIG_HIGHMEM
262 #define PageHighMem(page) is_highmem(page_zone(page))
264 #define PageHighMem(page) 0 /* needed to optimize away at compile time */
267 #define PageChecked(page) test_bit(PG_checked, &(page)->flags)
268 #define SetPageChecked(page) set_bit(PG_checked, &(page)->flags)
269 #define ClearPageChecked(page) clear_bit(PG_checked, &(page)->flags)
271 #define PageReserved(page) test_bit(PG_reserved, &(page)->flags)
272 #define SetPageReserved(page) set_bit(PG_reserved, &(page)->flags)
273 #define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags)
274 #define __ClearPageReserved(page) __clear_bit(PG_reserved, &(page)->flags)
276 #define SetPagePrivate(page) set_bit(PG_private, &(page)->flags)
277 #define ClearPagePrivate(page) clear_bit(PG_private, &(page)->flags)
278 #define PagePrivate(page) test_bit(PG_private, &(page)->flags)
279 #define __SetPagePrivate(page) __set_bit(PG_private, &(page)->flags)
280 #define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags)
282 #define PageWriteback(page) test_bit(PG_writeback, &(page)->flags)
283 #define SetPageWriteback(page) \
285 if (!test_and_set_bit(PG_writeback, \
287 inc_page_state(nr_writeback); \
289 #define TestSetPageWriteback(page) \
292 ret = test_and_set_bit(PG_writeback, \
295 inc_page_state(nr_writeback); \
298 #define ClearPageWriteback(page) \
300 if (test_and_clear_bit(PG_writeback, \
302 dec_page_state(nr_writeback); \
304 #define TestClearPageWriteback(page) \
307 ret = test_and_clear_bit(PG_writeback, \
310 dec_page_state(nr_writeback); \
314 #define PageNosave(page) test_bit(PG_nosave, &(page)->flags)
315 #define SetPageNosave(page) set_bit(PG_nosave, &(page)->flags)
316 #define TestSetPageNosave(page) test_and_set_bit(PG_nosave, &(page)->flags)
317 #define ClearPageNosave(page) clear_bit(PG_nosave, &(page)->flags)
318 #define TestClearPageNosave(page) test_and_clear_bit(PG_nosave, &(page)->flags)
320 #define PageNosaveFree(page) test_bit(PG_nosave_free, &(page)->flags)
321 #define SetPageNosaveFree(page) set_bit(PG_nosave_free, &(page)->flags)
322 #define ClearPageNosaveFree(page) clear_bit(PG_nosave_free, &(page)->flags)
324 #define PageBuddy(page) test_bit(PG_buddy, &(page)->flags)
325 #define __SetPageBuddy(page) __set_bit(PG_buddy, &(page)->flags)
326 #define __ClearPageBuddy(page) __clear_bit(PG_buddy, &(page)->flags)
328 #define PageMappedToDisk(page) test_bit(PG_mappedtodisk, &(page)->flags)
329 #define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags)
330 #define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags)
332 #define PageReclaim(page) test_bit(PG_reclaim, &(page)->flags)
333 #define SetPageReclaim(page) set_bit(PG_reclaim, &(page)->flags)
334 #define ClearPageReclaim(page) clear_bit(PG_reclaim, &(page)->flags)
335 #define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags)
337 #define PageCompound(page) test_bit(PG_compound, &(page)->flags)
338 #define SetPageCompound(page) set_bit(PG_compound, &(page)->flags)
339 #define ClearPageCompound(page) clear_bit(PG_compound, &(page)->flags)
342 #define PageSwapCache(page) test_bit(PG_swapcache, &(page)->flags)
343 #define SetPageSwapCache(page) set_bit(PG_swapcache, &(page)->flags)
344 #define ClearPageSwapCache(page) clear_bit(PG_swapcache, &(page)->flags)
346 #define PageSwapCache(page) 0
349 #define PageUncached(page) test_bit(PG_uncached, &(page)->flags)
350 #define SetPageUncached(page) set_bit(PG_uncached, &(page)->flags)
351 #define ClearPageUncached(page) clear_bit(PG_uncached, &(page)->flags)
353 struct page; /* forward declaration */
355 int test_clear_page_dirty(struct page *page);
356 int test_clear_page_writeback(struct page *page);
357 int test_set_page_writeback(struct page *page);
359 static inline void clear_page_dirty(struct page *page)
361 test_clear_page_dirty(page);
364 static inline void set_page_writeback(struct page *page)
366 test_set_page_writeback(page);
369 #endif /* PAGE_FLAGS_H */