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- /*
- * Macros for manipulating and testing page->flags
- */
- #ifndef PAGE_FLAGS_H
- #define PAGE_FLAGS_H
- #include <linux/types.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 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.
- *
- * 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.
- *
- * 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.
- *
- * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
- * file-backed pagecache (see mm/vmscan.c).
- *
- * 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...
- *
- * PG_buddy is set to indicate that the page is free and in the buddy system
- * (see mm/page_alloc.c).
- *
- */
- /*
- * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
- * 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.
- */
- #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) */
- #define PG_owner_priv_1 8 /* Owner use. If pagecache, fs may use*/
- #define PG_arch_1 9
- #define PG_reserved 10
- #define PG_private 11 /* If pagecache, has fs-private data */
- #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 /* Used for system suspend/resume */
- #define PG_buddy 19 /* Page is free, on buddy lists */
- /* PG_owner_priv_1 users should have descriptive aliases */
- #define PG_checked PG_owner_priv_1 /* Used by some filesystems */
- #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
- /*
- * 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)
- #ifdef CONFIG_S390
- static inline void SetPageUptodate(struct page *page)
- {
- if (!test_and_set_bit(PG_uptodate, &page->flags))
- page_test_and_clear_dirty(page);
- }
- #else
- #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)
- #define __ClearPageDirty(page) __clear_bit(PG_dirty, &(page)->flags)
- #define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags)
- #define PageLRU(page) test_bit(PG_lru, &(page)->flags)
- #define SetPageLRU(page) set_bit(PG_lru, &(page)->flags)
- #define ClearPageLRU(page) clear_bit(PG_lru, &(page)->flags)
- #define __ClearPageLRU(page) __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 __ClearPageActive(page) __clear_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)
- #ifdef CONFIG_HIGHMEM
- #define PageHighMem(page) is_highmem(page_zone(page))
- #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_zone_page_state(page, NR_WRITEBACK); \
- } while (0)
- #define TestSetPageWriteback(page) \
- ({ \
- int ret; \
- ret = test_and_set_bit(PG_writeback, \
- &(page)->flags); \
- if (!ret) \
- inc_zone_page_state(page, NR_WRITEBACK); \
- ret; \
- })
- #define ClearPageWriteback(page) \
- do { \
- if (test_and_clear_bit(PG_writeback, \
- &(page)->flags)) \
- dec_zone_page_state(page, NR_WRITEBACK); \
- } while (0)
- #define TestClearPageWriteback(page) \
- ({ \
- int ret; \
- ret = test_and_clear_bit(PG_writeback, \
- &(page)->flags); \
- if (ret) \
- dec_zone_page_state(page, 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 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)
- #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 */
- extern void cancel_dirty_page(struct page *page, unsigned int account_size);
- int test_clear_page_writeback(struct page *page);
- int test_set_page_writeback(struct page *page);
- static inline void set_page_writeback(struct page *page)
- {
- test_set_page_writeback(page);
- }
- #endif /* PAGE_FLAGS_H */
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