page-flags.h 10.2 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7
/*
 * Macros for manipulating and testing page->flags
 */

#ifndef PAGE_FLAGS_H
#define PAGE_FLAGS_H

A
Andrew Morton 已提交
8 9
#include <linux/types.h>

L
Linus Torvalds 已提交
10 11 12 13 14 15
/*
 * Various page->flags bits:
 *
 * PG_reserved is set for special pages, which can never be swapped out. Some
 * of them might not even exist (eg empty_bad_page)...
 *
N
Nick Piggin 已提交
16 17 18
 * The PG_private bitflag is set on pagecache pages if they contain filesystem
 * specific data (which is normally at page->private). It can be used by
 * private allocations for its own usage.
L
Linus Torvalds 已提交
19
 *
N
Nick Piggin 已提交
20 21 22 23 24 25 26 27 28
 * During initiation of disk I/O, PG_locked is set. This bit is set before I/O
 * and cleared when writeback _starts_ or when read _completes_. PG_writeback
 * is set before writeback starts and cleared when it finishes.
 *
 * PG_locked also pins a page in pagecache, and blocks truncation of the file
 * while it is held.
 *
 * page_waitqueue(page) is a wait queue of all tasks waiting for the page
 * to become unlocked.
L
Linus Torvalds 已提交
29 30 31 32
 *
 * PG_uptodate tells whether the page's contents is valid.  When a read
 * completes, the page becomes uptodate, unless a disk I/O error happened.
 *
N
Nick Piggin 已提交
33 34
 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
 * file-backed pagecache (see mm/vmscan.c).
L
Linus Torvalds 已提交
35 36 37 38 39 40 41 42 43 44 45
 *
 * PG_error is set to indicate that an I/O error occurred on this page.
 *
 * PG_arch_1 is an architecture specific page state bit.  The generic code
 * guarantees that this bit is cleared for a page when it first is entered into
 * the page cache.
 *
 * PG_highmem pages are not permanently mapped into the kernel virtual address
 * space, they need to be kmapped separately for doing IO on the pages.  The
 * struct page (these bits with information) are always mapped into kernel
 * address space...
N
Nick Piggin 已提交
46 47 48 49
 *
 * PG_buddy is set to indicate that the page is free and in the buddy system
 * (see mm/page_alloc.c).
 *
L
Linus Torvalds 已提交
50 51 52 53
 */

/*
 * Don't use the *_dontuse flags.  Use the macros.  Otherwise you'll break
54 55 56 57 58 59 60 61 62 63 64 65 66 67
 * locked- and dirty-page accounting.
 *
 * The page flags field is split into two parts, the main flags area
 * which extends from the low bits upwards, and the fields area which
 * extends from the high bits downwards.
 *
 *  | FIELD | ... | FLAGS |
 *  N-1     ^             0
 *          (N-FLAGS_RESERVED)
 *
 * The fields area is reserved for fields mapping zone, node and SPARSEMEM
 * section.  The boundry between these two areas is defined by
 * FLAGS_RESERVED which defines the width of the fields section
 * (see linux/mmzone.h).  New flags must _not_ overlap with this area.
L
Linus Torvalds 已提交
68 69 70 71 72 73 74 75 76 77 78
 */
#define PG_locked	 	 0	/* Page is locked. Don't touch. */
#define PG_error		 1
#define PG_referenced		 2
#define PG_uptodate		 3

#define PG_dirty	 	 4
#define PG_lru			 5
#define PG_active		 6
#define PG_slab			 7	/* slab debug (Suparna wants this) */

B
Badari Pulavarty 已提交
79 80 81
#define PG_checked		 8	/* kill me in 2.5.<early>. */
#define PG_arch_1		 9
#define PG_reserved		10
N
Nick Piggin 已提交
82
#define PG_private		11	/* If pagecache, has fs-private data */
B
Badari Pulavarty 已提交
83 84 85 86 87 88 89 90

#define PG_writeback		12	/* Page is under writeback */
#define PG_nosave		13	/* Used for system suspend/resume */
#define PG_compound		14	/* Part of a compound page */
#define PG_swapcache		15	/* Swap page: swp_entry_t in private */

#define PG_mappedtodisk		16	/* Has blocks allocated on-disk */
#define PG_reclaim		17	/* To be reclaimed asap */
N
Nick Piggin 已提交
91
#define PG_nosave_free		18	/* Used for system suspend/resume */
92 93
#define PG_buddy		19	/* Page is free, on buddy lists */

A
Andrew Morton 已提交
94 95 96 97 98 99 100 101 102 103 104

#if (BITS_PER_LONG > 32)
/*
 * 64-bit-only flags build down from bit 31
 *
 * 32 bit  -------------------------------| FIELDS |       FLAGS         |
 * 64 bit  |           FIELDS             | ??????         FLAGS         |
 *         63                            32                              0
 */
#define PG_uncached		31	/* Page has been mapped as uncached */
#endif
L
Linus Torvalds 已提交
105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129

/*
 * Manipulation of page state flags
 */
#define PageLocked(page)		\
		test_bit(PG_locked, &(page)->flags)
#define SetPageLocked(page)		\
		set_bit(PG_locked, &(page)->flags)
#define TestSetPageLocked(page)		\
		test_and_set_bit(PG_locked, &(page)->flags)
#define ClearPageLocked(page)		\
		clear_bit(PG_locked, &(page)->flags)
#define TestClearPageLocked(page)	\
		test_and_clear_bit(PG_locked, &(page)->flags)

#define PageError(page)		test_bit(PG_error, &(page)->flags)
#define SetPageError(page)	set_bit(PG_error, &(page)->flags)
#define ClearPageError(page)	clear_bit(PG_error, &(page)->flags)

#define PageReferenced(page)	test_bit(PG_referenced, &(page)->flags)
#define SetPageReferenced(page)	set_bit(PG_referenced, &(page)->flags)
#define ClearPageReferenced(page)	clear_bit(PG_referenced, &(page)->flags)
#define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags)

#define PageUptodate(page)	test_bit(PG_uptodate, &(page)->flags)
130 131 132 133 134 135 136 137
#ifdef CONFIG_S390
#define SetPageUptodate(_page) \
	do {								      \
		struct page *__page = (_page);				      \
		if (!test_and_set_bit(PG_uptodate, &__page->flags))	      \
			page_test_and_clear_dirty(_page);		      \
	} while (0)
#else
L
Linus Torvalds 已提交
138 139 140 141 142 143 144 145
#define SetPageUptodate(page)	set_bit(PG_uptodate, &(page)->flags)
#endif
#define ClearPageUptodate(page)	clear_bit(PG_uptodate, &(page)->flags)

#define PageDirty(page)		test_bit(PG_dirty, &(page)->flags)
#define SetPageDirty(page)	set_bit(PG_dirty, &(page)->flags)
#define TestSetPageDirty(page)	test_and_set_bit(PG_dirty, &(page)->flags)
#define ClearPageDirty(page)	clear_bit(PG_dirty, &(page)->flags)
N
Nick Piggin 已提交
146
#define __ClearPageDirty(page)	__clear_bit(PG_dirty, &(page)->flags)
L
Linus Torvalds 已提交
147 148 149
#define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags)

#define PageLRU(page)		test_bit(PG_lru, &(page)->flags)
N
Nick Piggin 已提交
150 151
#define SetPageLRU(page)	set_bit(PG_lru, &(page)->flags)
#define ClearPageLRU(page)	clear_bit(PG_lru, &(page)->flags)
N
Nick Piggin 已提交
152
#define __ClearPageLRU(page)	__clear_bit(PG_lru, &(page)->flags)
L
Linus Torvalds 已提交
153 154 155 156

#define PageActive(page)	test_bit(PG_active, &(page)->flags)
#define SetPageActive(page)	set_bit(PG_active, &(page)->flags)
#define ClearPageActive(page)	clear_bit(PG_active, &(page)->flags)
N
Nick Piggin 已提交
157
#define __ClearPageActive(page)	__clear_bit(PG_active, &(page)->flags)
L
Linus Torvalds 已提交
158 159

#define PageSlab(page)		test_bit(PG_slab, &(page)->flags)
N
Nick Piggin 已提交
160 161
#define __SetPageSlab(page)	__set_bit(PG_slab, &(page)->flags)
#define __ClearPageSlab(page)	__clear_bit(PG_slab, &(page)->flags)
L
Linus Torvalds 已提交
162 163

#ifdef CONFIG_HIGHMEM
B
Badari Pulavarty 已提交
164
#define PageHighMem(page)	is_highmem(page_zone(page))
L
Linus Torvalds 已提交
165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188
#else
#define PageHighMem(page)	0 /* needed to optimize away at compile time */
#endif

#define PageChecked(page)	test_bit(PG_checked, &(page)->flags)
#define SetPageChecked(page)	set_bit(PG_checked, &(page)->flags)
#define ClearPageChecked(page)	clear_bit(PG_checked, &(page)->flags)

#define PageReserved(page)	test_bit(PG_reserved, &(page)->flags)
#define SetPageReserved(page)	set_bit(PG_reserved, &(page)->flags)
#define ClearPageReserved(page)	clear_bit(PG_reserved, &(page)->flags)
#define __ClearPageReserved(page)	__clear_bit(PG_reserved, &(page)->flags)

#define SetPagePrivate(page)	set_bit(PG_private, &(page)->flags)
#define ClearPagePrivate(page)	clear_bit(PG_private, &(page)->flags)
#define PagePrivate(page)	test_bit(PG_private, &(page)->flags)
#define __SetPagePrivate(page)  __set_bit(PG_private, &(page)->flags)
#define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags)

#define PageWriteback(page)	test_bit(PG_writeback, &(page)->flags)
#define SetPageWriteback(page)						\
	do {								\
		if (!test_and_set_bit(PG_writeback,			\
				&(page)->flags))			\
189
			inc_zone_page_state(page, NR_WRITEBACK);	\
L
Linus Torvalds 已提交
190 191 192 193 194 195 196
	} while (0)
#define TestSetPageWriteback(page)					\
	({								\
		int ret;						\
		ret = test_and_set_bit(PG_writeback,			\
					&(page)->flags);		\
		if (!ret)						\
197
			inc_zone_page_state(page, NR_WRITEBACK);	\
L
Linus Torvalds 已提交
198 199 200 201 202 203
		ret;							\
	})
#define ClearPageWriteback(page)					\
	do {								\
		if (test_and_clear_bit(PG_writeback,			\
				&(page)->flags))			\
204
			dec_zone_page_state(page, NR_WRITEBACK);	\
L
Linus Torvalds 已提交
205 206 207 208 209 210 211
	} while (0)
#define TestClearPageWriteback(page)					\
	({								\
		int ret;						\
		ret = test_and_clear_bit(PG_writeback,			\
				&(page)->flags);			\
		if (ret)						\
212
			dec_zone_page_state(page, NR_WRITEBACK);	\
L
Linus Torvalds 已提交
213 214 215 216 217 218 219 220 221 222 223 224 225
		ret;							\
	})

#define PageNosave(page)	test_bit(PG_nosave, &(page)->flags)
#define SetPageNosave(page)	set_bit(PG_nosave, &(page)->flags)
#define TestSetPageNosave(page)	test_and_set_bit(PG_nosave, &(page)->flags)
#define ClearPageNosave(page)		clear_bit(PG_nosave, &(page)->flags)
#define TestClearPageNosave(page)	test_and_clear_bit(PG_nosave, &(page)->flags)

#define PageNosaveFree(page)	test_bit(PG_nosave_free, &(page)->flags)
#define SetPageNosaveFree(page)	set_bit(PG_nosave_free, &(page)->flags)
#define ClearPageNosaveFree(page)		clear_bit(PG_nosave_free, &(page)->flags)

226 227 228 229
#define PageBuddy(page)		test_bit(PG_buddy, &(page)->flags)
#define __SetPageBuddy(page)	__set_bit(PG_buddy, &(page)->flags)
#define __ClearPageBuddy(page)	__clear_bit(PG_buddy, &(page)->flags)

L
Linus Torvalds 已提交
230 231 232 233 234 235 236 237 238 239
#define PageMappedToDisk(page)	test_bit(PG_mappedtodisk, &(page)->flags)
#define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags)
#define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags)

#define PageReclaim(page)	test_bit(PG_reclaim, &(page)->flags)
#define SetPageReclaim(page)	set_bit(PG_reclaim, &(page)->flags)
#define ClearPageReclaim(page)	clear_bit(PG_reclaim, &(page)->flags)
#define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags)

#define PageCompound(page)	test_bit(PG_compound, &(page)->flags)
240 241
#define __SetPageCompound(page)	__set_bit(PG_compound, &(page)->flags)
#define __ClearPageCompound(page) __clear_bit(PG_compound, &(page)->flags)
L
Linus Torvalds 已提交
242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271

#ifdef CONFIG_SWAP
#define PageSwapCache(page)	test_bit(PG_swapcache, &(page)->flags)
#define SetPageSwapCache(page)	set_bit(PG_swapcache, &(page)->flags)
#define ClearPageSwapCache(page) clear_bit(PG_swapcache, &(page)->flags)
#else
#define PageSwapCache(page)	0
#endif

#define PageUncached(page)	test_bit(PG_uncached, &(page)->flags)
#define SetPageUncached(page)	set_bit(PG_uncached, &(page)->flags)
#define ClearPageUncached(page)	clear_bit(PG_uncached, &(page)->flags)

struct page;	/* forward declaration */

int test_clear_page_dirty(struct page *page);
int test_clear_page_writeback(struct page *page);
int test_set_page_writeback(struct page *page);

static inline void clear_page_dirty(struct page *page)
{
	test_clear_page_dirty(page);
}

static inline void set_page_writeback(struct page *page)
{
	test_set_page_writeback(page);
}

#endif	/* PAGE_FLAGS_H */