page-flags.h 14.0 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
/*
 * Macros for manipulating and testing page->flags
 */

#ifndef PAGE_FLAGS_H
#define PAGE_FLAGS_H

#include <linux/percpu.h>
#include <linux/cache.h>
#include <asm/pgtable.h>

/*
 * 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)...
 *
 * The PG_private bitflag is set if page->private contains a valid value.
 *
 * During disk I/O, PG_locked is used. This bit is set before I/O and
 * reset when I/O completes. page_waitqueue(page) is a wait queue of all tasks
 * waiting for the I/O on this page to complete.
 *
 * 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.
 *
 * For choosing which pages to swap out, inode pages carry a PG_referenced bit,
 * which is set any time the system accesses that page through the (mapping,
 * index) hash table.  This referenced bit, together with the referenced bit
 * in the page tables, is used to manipulate page->age and move the page across
 * the active, inactive_dirty and inactive_clean lists.
 *
 * Note that the referenced bit, the page->lru list_head and the active,
 * inactive_dirty and inactive_clean lists are protected by the
 * zone->lru_lock, and *NOT* by the usual PG_locked bit!
 *
 * 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...
 */

/*
 * Don't use the *_dontuse flags.  Use the macros.  Otherwise you'll break
 * locked- and dirty-page accounting.  The top eight bits of page->flags are
 * used for page->zone, so putting flag bits there doesn't work.
 */
#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
64 65 66 67 68 69 70 71 72 73 74 75 76 77
#define PG_checked		 8	/* kill me in 2.5.<early>. */
#define PG_arch_1		 9
#define PG_reserved		10
#define PG_private		11	/* Has something at ->private */

#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 */
#define PG_nosave_free		18	/* Free, should not be written */
#define PG_uncached		19	/* Page has been mapped as uncached */
L
Linus Torvalds 已提交
78 79 80 81

/*
 * Global page accounting.  One instance per CPU.  Only unsigned longs are
 * allowed.
N
Nick Piggin 已提交
82 83 84 85 86 87 88 89 90
 *
 * - Fields can be modified with xxx_page_state and xxx_page_state_zone at
 * any time safely (which protects the instance from modification by
 * interrupt.
 * - The __xxx_page_state variants can be used safely when interrupts are
 * disabled.
 * - The __xxx_page_state variants can be used if the field is only
 * modified from process context, or only modified from interrupt context.
 * In this case, the field should be commented here.
L
Linus Torvalds 已提交
91 92 93 94 95 96
 */
struct page_state {
	unsigned long nr_dirty;		/* Dirty writeable pages */
	unsigned long nr_writeback;	/* Pages under writeback */
	unsigned long nr_unstable;	/* NFS unstable pages */
	unsigned long nr_page_table_pages;/* Pages used for pagetables */
N
Nick Piggin 已提交
97 98
	unsigned long nr_mapped;	/* mapped into pagetables.
					 * only modified from process context */
L
Linus Torvalds 已提交
99 100 101 102 103 104 105 106 107 108 109 110
	unsigned long nr_slab;		/* In slab */
#define GET_PAGE_STATE_LAST nr_slab

	/*
	 * The below are zeroed by get_page_state().  Use get_full_page_state()
	 * to add up all these.
	 */
	unsigned long pgpgin;		/* Disk reads */
	unsigned long pgpgout;		/* Disk writes */
	unsigned long pswpin;		/* swap reads */
	unsigned long pswpout;		/* swap writes */

N
Nick Piggin 已提交
111
	unsigned long pgalloc_high;	/* page allocations */
L
Linus Torvalds 已提交
112
	unsigned long pgalloc_normal;
N
Nick Piggin 已提交
113
	unsigned long pgalloc_dma32;
L
Linus Torvalds 已提交
114
	unsigned long pgalloc_dma;
N
Nick Piggin 已提交
115

L
Linus Torvalds 已提交
116 117 118 119 120 121
	unsigned long pgfree;		/* page freeings */
	unsigned long pgactivate;	/* pages moved inactive->active */
	unsigned long pgdeactivate;	/* pages moved active->inactive */

	unsigned long pgfault;		/* faults (major+minor) */
	unsigned long pgmajfault;	/* faults (major only) */
N
Nick Piggin 已提交
122

L
Linus Torvalds 已提交
123 124
	unsigned long pgrefill_high;	/* inspected in refill_inactive_zone */
	unsigned long pgrefill_normal;
N
Nick Piggin 已提交
125
	unsigned long pgrefill_dma32;
L
Linus Torvalds 已提交
126 127 128 129
	unsigned long pgrefill_dma;

	unsigned long pgsteal_high;	/* total highmem pages reclaimed */
	unsigned long pgsteal_normal;
N
Nick Piggin 已提交
130
	unsigned long pgsteal_dma32;
L
Linus Torvalds 已提交
131
	unsigned long pgsteal_dma;
N
Nick Piggin 已提交
132

L
Linus Torvalds 已提交
133 134
	unsigned long pgscan_kswapd_high;/* total highmem pages scanned */
	unsigned long pgscan_kswapd_normal;
N
Nick Piggin 已提交
135
	unsigned long pgscan_kswapd_dma32;
L
Linus Torvalds 已提交
136
	unsigned long pgscan_kswapd_dma;
N
Nick Piggin 已提交
137

L
Linus Torvalds 已提交
138 139
	unsigned long pgscan_direct_high;/* total highmem pages scanned */
	unsigned long pgscan_direct_normal;
N
Nick Piggin 已提交
140
	unsigned long pgscan_direct_dma32;
L
Linus Torvalds 已提交
141 142
	unsigned long pgscan_direct_dma;

N
Nick Piggin 已提交
143
	unsigned long pginodesteal;	/* pages reclaimed via inode freeing */
L
Linus Torvalds 已提交
144 145 146 147 148 149 150
	unsigned long slabs_scanned;	/* slab objects scanned */
	unsigned long kswapd_steal;	/* pages reclaimed by kswapd */
	unsigned long kswapd_inodesteal;/* reclaimed via kswapd inode freeing */
	unsigned long pageoutrun;	/* kswapd's calls to page reclaim */
	unsigned long allocstall;	/* direct reclaim calls */

	unsigned long pgrotated;	/* pages rotated to tail of the LRU */
151
	unsigned long nr_bounce;	/* pages for bounce buffers */
L
Linus Torvalds 已提交
152 153 154
};

extern void get_page_state(struct page_state *ret);
155
extern void get_page_state_node(struct page_state *ret, int node);
L
Linus Torvalds 已提交
156
extern void get_full_page_state(struct page_state *ret);
N
Nick Piggin 已提交
157 158 159
extern unsigned long read_page_state_offset(unsigned long offset);
extern void mod_page_state_offset(unsigned long offset, unsigned long delta);
extern void __mod_page_state_offset(unsigned long offset, unsigned long delta);
L
Linus Torvalds 已提交
160 161

#define read_page_state(member) \
N
Nick Piggin 已提交
162
	read_page_state_offset(offsetof(struct page_state, member))
L
Linus Torvalds 已提交
163 164

#define mod_page_state(member, delta)	\
N
Nick Piggin 已提交
165
	mod_page_state_offset(offsetof(struct page_state, member), (delta))
L
Linus Torvalds 已提交
166

N
Nick Piggin 已提交
167 168
#define __mod_page_state(member, delta)	\
	__mod_page_state_offset(offsetof(struct page_state, member), (delta))
L
Linus Torvalds 已提交
169

N
Nick Piggin 已提交
170 171 172 173 174 175 176 177 178 179 180 181 182 183
#define inc_page_state(member)		mod_page_state(member, 1UL)
#define dec_page_state(member)		mod_page_state(member, 0UL - 1)
#define add_page_state(member,delta)	mod_page_state(member, (delta))
#define sub_page_state(member,delta)	mod_page_state(member, 0UL - (delta))

#define __inc_page_state(member)	__mod_page_state(member, 1UL)
#define __dec_page_state(member)	__mod_page_state(member, 0UL - 1)
#define __add_page_state(member,delta)	__mod_page_state(member, (delta))
#define __sub_page_state(member,delta)	__mod_page_state(member, 0UL - (delta))

#define page_state(member) (*__page_state(offsetof(struct page_state, member)))

#define state_zone_offset(zone, member)					\
({									\
N
Nick Piggin 已提交
184 185 186 187 188 189 190 191 192
	unsigned offset;						\
	if (is_highmem(zone))						\
		offset = offsetof(struct page_state, member##_high);	\
	else if (is_normal(zone))					\
		offset = offsetof(struct page_state, member##_normal);	\
	else if (is_dma32(zone))					\
		offset = offsetof(struct page_state, member##_dma32);	\
	else								\
		offset = offsetof(struct page_state, member##_dma);	\
N
Nick Piggin 已提交
193 194 195 196 197 198 199 200 201 202 203
	offset;								\
})

#define __mod_page_state_zone(zone, member, delta)			\
 do {									\
	__mod_page_state_offset(state_zone_offset(zone, member), (delta)); \
 } while (0)

#define mod_page_state_zone(zone, member, delta)			\
 do {									\
	mod_page_state_offset(state_zone_offset(zone, member), (delta)); \
N
Nick Piggin 已提交
204
 } while (0)
L
Linus Torvalds 已提交
205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238

/*
 * 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)
#ifndef SetPageUptodate
#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
239
#define __ClearPageDirty(page)	__clear_bit(PG_dirty, &(page)->flags)
L
Linus Torvalds 已提交
240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259
#define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags)

#define SetPageLRU(page)	set_bit(PG_lru, &(page)->flags)
#define PageLRU(page)		test_bit(PG_lru, &(page)->flags)
#define TestSetPageLRU(page)	test_and_set_bit(PG_lru, &(page)->flags)
#define TestClearPageLRU(page)	test_and_clear_bit(PG_lru, &(page)->flags)

#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)
#define TestClearPageActive(page) test_and_clear_bit(PG_active, &(page)->flags)
#define TestSetPageActive(page) test_and_set_bit(PG_active, &(page)->flags)

#define PageSlab(page)		test_bit(PG_slab, &(page)->flags)
#define SetPageSlab(page)	set_bit(PG_slab, &(page)->flags)
#define ClearPageSlab(page)	clear_bit(PG_slab, &(page)->flags)
#define TestClearPageSlab(page)	test_and_clear_bit(PG_slab, &(page)->flags)
#define TestSetPageSlab(page)	test_and_set_bit(PG_slab, &(page)->flags)

#ifdef CONFIG_HIGHMEM
B
Badari Pulavarty 已提交
260
#define PageHighMem(page)	is_highmem(page_zone(page))
L
Linus Torvalds 已提交
261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363
#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))			\
			inc_page_state(nr_writeback);			\
	} while (0)
#define TestSetPageWriteback(page)					\
	({								\
		int ret;						\
		ret = test_and_set_bit(PG_writeback,			\
					&(page)->flags);		\
		if (!ret)						\
			inc_page_state(nr_writeback);			\
		ret;							\
	})
#define ClearPageWriteback(page)					\
	do {								\
		if (test_and_clear_bit(PG_writeback,			\
				&(page)->flags))			\
			dec_page_state(nr_writeback);			\
	} while (0)
#define TestClearPageWriteback(page)					\
	({								\
		int ret;						\
		ret = test_and_clear_bit(PG_writeback,			\
				&(page)->flags);			\
		if (ret)						\
			dec_page_state(nr_writeback);			\
		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)

#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)
#define SetPageCompound(page)	set_bit(PG_compound, &(page)->flags)
#define ClearPageCompound(page)	clear_bit(PG_compound, &(page)->flags)

#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 */