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326 lines
13 KiB
326 lines
13 KiB
/*
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* Macros for manipulating and testing page->flags
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*/
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#ifndef PAGE_FLAGS_H
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#define PAGE_FLAGS_H
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#include <linux/percpu.h>
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#include <linux/cache.h>
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#include <asm/pgtable.h>
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/*
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* Various page->flags bits:
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*
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* PG_reserved is set for special pages, which can never be swapped out. Some
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* of them might not even exist (eg empty_bad_page)...
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*
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* The PG_private bitflag is set if page->private contains a valid value.
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*
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* During disk I/O, PG_locked is used. This bit is set before I/O and
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* reset when I/O completes. page_waitqueue(page) is a wait queue of all tasks
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* waiting for the I/O on this page to complete.
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*
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* PG_uptodate tells whether the page's contents is valid. When a read
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* completes, the page becomes uptodate, unless a disk I/O error happened.
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*
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* For choosing which pages to swap out, inode pages carry a PG_referenced bit,
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* which is set any time the system accesses that page through the (mapping,
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* index) hash table. This referenced bit, together with the referenced bit
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* in the page tables, is used to manipulate page->age and move the page across
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* the active, inactive_dirty and inactive_clean lists.
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*
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* Note that the referenced bit, the page->lru list_head and the active,
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* inactive_dirty and inactive_clean lists are protected by the
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* zone->lru_lock, and *NOT* by the usual PG_locked bit!
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*
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* PG_error is set to indicate that an I/O error occurred on this page.
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*
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* PG_arch_1 is an architecture specific page state bit. The generic code
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* guarantees that this bit is cleared for a page when it first is entered into
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* the page cache.
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*
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* PG_highmem pages are not permanently mapped into the kernel virtual address
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* space, they need to be kmapped separately for doing IO on the pages. The
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* struct page (these bits with information) are always mapped into kernel
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* address space...
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*/
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/*
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* Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
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* locked- and dirty-page accounting. The top eight bits of page->flags are
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* used for page->zone, so putting flag bits there doesn't work.
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*/
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#define PG_locked 0 /* Page is locked. Don't touch. */
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#define PG_error 1
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#define PG_referenced 2
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#define PG_uptodate 3
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#define PG_dirty 4
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#define PG_lru 5
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#define PG_active 6
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#define PG_slab 7 /* slab debug (Suparna wants this) */
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#define PG_checked 8 /* kill me in 2.5.<early>. */
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#define PG_arch_1 9
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#define PG_reserved 10
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#define PG_private 11 /* Has something at ->private */
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#define PG_writeback 12 /* Page is under writeback */
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#define PG_nosave 13 /* Used for system suspend/resume */
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#define PG_compound 14 /* Part of a compound page */
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#define PG_swapcache 15 /* Swap page: swp_entry_t in private */
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#define PG_mappedtodisk 16 /* Has blocks allocated on-disk */
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#define PG_reclaim 17 /* To be reclaimed asap */
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#define PG_nosave_free 18 /* Free, should not be written */
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#define PG_uncached 19 /* Page has been mapped as uncached */
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/*
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* Global page accounting. One instance per CPU. Only unsigned longs are
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* allowed.
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*/
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struct page_state {
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unsigned long nr_dirty; /* Dirty writeable pages */
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unsigned long nr_writeback; /* Pages under writeback */
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unsigned long nr_unstable; /* NFS unstable pages */
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unsigned long nr_page_table_pages;/* Pages used for pagetables */
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unsigned long nr_mapped; /* mapped into pagetables */
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unsigned long nr_slab; /* In slab */
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#define GET_PAGE_STATE_LAST nr_slab
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/*
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* The below are zeroed by get_page_state(). Use get_full_page_state()
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* to add up all these.
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*/
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unsigned long pgpgin; /* Disk reads */
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unsigned long pgpgout; /* Disk writes */
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unsigned long pswpin; /* swap reads */
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unsigned long pswpout; /* swap writes */
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unsigned long pgalloc_high; /* page allocations */
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unsigned long pgalloc_normal;
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unsigned long pgalloc_dma;
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unsigned long pgfree; /* page freeings */
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unsigned long pgactivate; /* pages moved inactive->active */
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unsigned long pgdeactivate; /* pages moved active->inactive */
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unsigned long pgfault; /* faults (major+minor) */
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unsigned long pgmajfault; /* faults (major only) */
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unsigned long pgrefill_high; /* inspected in refill_inactive_zone */
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unsigned long pgrefill_normal;
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unsigned long pgrefill_dma;
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unsigned long pgsteal_high; /* total highmem pages reclaimed */
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unsigned long pgsteal_normal;
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unsigned long pgsteal_dma;
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unsigned long pgscan_kswapd_high;/* total highmem pages scanned */
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unsigned long pgscan_kswapd_normal;
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unsigned long pgscan_kswapd_dma;
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unsigned long pgscan_direct_high;/* total highmem pages scanned */
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unsigned long pgscan_direct_normal;
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unsigned long pgscan_direct_dma;
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unsigned long pginodesteal; /* pages reclaimed via inode freeing */
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unsigned long slabs_scanned; /* slab objects scanned */
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unsigned long kswapd_steal; /* pages reclaimed by kswapd */
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unsigned long kswapd_inodesteal;/* reclaimed via kswapd inode freeing */
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unsigned long pageoutrun; /* kswapd's calls to page reclaim */
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unsigned long allocstall; /* direct reclaim calls */
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unsigned long pgrotated; /* pages rotated to tail of the LRU */
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unsigned long nr_bounce; /* pages for bounce buffers */
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};
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extern void get_page_state(struct page_state *ret);
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extern void get_page_state_node(struct page_state *ret, int node);
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extern void get_full_page_state(struct page_state *ret);
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extern unsigned long __read_page_state(unsigned long offset);
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extern void __mod_page_state(unsigned long offset, unsigned long delta);
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#define read_page_state(member) \
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__read_page_state(offsetof(struct page_state, member))
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#define mod_page_state(member, delta) \
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__mod_page_state(offsetof(struct page_state, member), (delta))
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#define inc_page_state(member) mod_page_state(member, 1UL)
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#define dec_page_state(member) mod_page_state(member, 0UL - 1)
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#define add_page_state(member,delta) mod_page_state(member, (delta))
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#define sub_page_state(member,delta) mod_page_state(member, 0UL - (delta))
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#define mod_page_state_zone(zone, member, delta) \
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do { \
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unsigned offset; \
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if (is_highmem(zone)) \
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offset = offsetof(struct page_state, member##_high); \
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else if (is_normal(zone)) \
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offset = offsetof(struct page_state, member##_normal); \
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else \
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offset = offsetof(struct page_state, member##_dma); \
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__mod_page_state(offset, (delta)); \
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} while (0)
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/*
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* Manipulation of page state flags
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*/
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#define PageLocked(page) \
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test_bit(PG_locked, &(page)->flags)
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#define SetPageLocked(page) \
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set_bit(PG_locked, &(page)->flags)
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#define TestSetPageLocked(page) \
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test_and_set_bit(PG_locked, &(page)->flags)
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#define ClearPageLocked(page) \
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clear_bit(PG_locked, &(page)->flags)
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#define TestClearPageLocked(page) \
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test_and_clear_bit(PG_locked, &(page)->flags)
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#define PageError(page) test_bit(PG_error, &(page)->flags)
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#define SetPageError(page) set_bit(PG_error, &(page)->flags)
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#define ClearPageError(page) clear_bit(PG_error, &(page)->flags)
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#define PageReferenced(page) test_bit(PG_referenced, &(page)->flags)
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#define SetPageReferenced(page) set_bit(PG_referenced, &(page)->flags)
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#define ClearPageReferenced(page) clear_bit(PG_referenced, &(page)->flags)
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#define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags)
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#define PageUptodate(page) test_bit(PG_uptodate, &(page)->flags)
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#ifndef SetPageUptodate
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#define SetPageUptodate(page) set_bit(PG_uptodate, &(page)->flags)
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#endif
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#define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags)
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#define PageDirty(page) test_bit(PG_dirty, &(page)->flags)
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#define SetPageDirty(page) set_bit(PG_dirty, &(page)->flags)
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#define TestSetPageDirty(page) test_and_set_bit(PG_dirty, &(page)->flags)
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#define ClearPageDirty(page) clear_bit(PG_dirty, &(page)->flags)
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#define __ClearPageDirty(page) __clear_bit(PG_dirty, &(page)->flags)
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#define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags)
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#define SetPageLRU(page) set_bit(PG_lru, &(page)->flags)
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#define PageLRU(page) test_bit(PG_lru, &(page)->flags)
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#define TestSetPageLRU(page) test_and_set_bit(PG_lru, &(page)->flags)
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#define TestClearPageLRU(page) test_and_clear_bit(PG_lru, &(page)->flags)
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#define PageActive(page) test_bit(PG_active, &(page)->flags)
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#define SetPageActive(page) set_bit(PG_active, &(page)->flags)
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#define ClearPageActive(page) clear_bit(PG_active, &(page)->flags)
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#define TestClearPageActive(page) test_and_clear_bit(PG_active, &(page)->flags)
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#define TestSetPageActive(page) test_and_set_bit(PG_active, &(page)->flags)
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#define PageSlab(page) test_bit(PG_slab, &(page)->flags)
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#define SetPageSlab(page) set_bit(PG_slab, &(page)->flags)
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#define ClearPageSlab(page) clear_bit(PG_slab, &(page)->flags)
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#define TestClearPageSlab(page) test_and_clear_bit(PG_slab, &(page)->flags)
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#define TestSetPageSlab(page) test_and_set_bit(PG_slab, &(page)->flags)
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#ifdef CONFIG_HIGHMEM
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#define PageHighMem(page) is_highmem(page_zone(page))
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#else
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#define PageHighMem(page) 0 /* needed to optimize away at compile time */
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#endif
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#define PageChecked(page) test_bit(PG_checked, &(page)->flags)
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#define SetPageChecked(page) set_bit(PG_checked, &(page)->flags)
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#define ClearPageChecked(page) clear_bit(PG_checked, &(page)->flags)
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#define PageReserved(page) test_bit(PG_reserved, &(page)->flags)
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#define SetPageReserved(page) set_bit(PG_reserved, &(page)->flags)
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#define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags)
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#define __ClearPageReserved(page) __clear_bit(PG_reserved, &(page)->flags)
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#define SetPagePrivate(page) set_bit(PG_private, &(page)->flags)
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#define ClearPagePrivate(page) clear_bit(PG_private, &(page)->flags)
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#define PagePrivate(page) test_bit(PG_private, &(page)->flags)
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#define __SetPagePrivate(page) __set_bit(PG_private, &(page)->flags)
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#define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags)
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#define PageWriteback(page) test_bit(PG_writeback, &(page)->flags)
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#define SetPageWriteback(page) \
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do { \
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if (!test_and_set_bit(PG_writeback, \
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&(page)->flags)) \
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inc_page_state(nr_writeback); \
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} while (0)
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#define TestSetPageWriteback(page) \
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({ \
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int ret; \
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ret = test_and_set_bit(PG_writeback, \
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&(page)->flags); \
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if (!ret) \
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inc_page_state(nr_writeback); \
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ret; \
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})
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#define ClearPageWriteback(page) \
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do { \
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if (test_and_clear_bit(PG_writeback, \
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&(page)->flags)) \
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dec_page_state(nr_writeback); \
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} while (0)
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#define TestClearPageWriteback(page) \
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({ \
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int ret; \
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ret = test_and_clear_bit(PG_writeback, \
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&(page)->flags); \
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if (ret) \
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dec_page_state(nr_writeback); \
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ret; \
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})
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#define PageNosave(page) test_bit(PG_nosave, &(page)->flags)
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#define SetPageNosave(page) set_bit(PG_nosave, &(page)->flags)
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#define TestSetPageNosave(page) test_and_set_bit(PG_nosave, &(page)->flags)
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#define ClearPageNosave(page) clear_bit(PG_nosave, &(page)->flags)
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#define TestClearPageNosave(page) test_and_clear_bit(PG_nosave, &(page)->flags)
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#define PageNosaveFree(page) test_bit(PG_nosave_free, &(page)->flags)
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#define SetPageNosaveFree(page) set_bit(PG_nosave_free, &(page)->flags)
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#define ClearPageNosaveFree(page) clear_bit(PG_nosave_free, &(page)->flags)
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#define PageMappedToDisk(page) test_bit(PG_mappedtodisk, &(page)->flags)
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#define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags)
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#define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags)
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#define PageReclaim(page) test_bit(PG_reclaim, &(page)->flags)
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#define SetPageReclaim(page) set_bit(PG_reclaim, &(page)->flags)
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#define ClearPageReclaim(page) clear_bit(PG_reclaim, &(page)->flags)
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#define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags)
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#ifdef CONFIG_HUGETLB_PAGE
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#define PageCompound(page) test_bit(PG_compound, &(page)->flags)
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#else
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#define PageCompound(page) 0
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#endif
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#define SetPageCompound(page) set_bit(PG_compound, &(page)->flags)
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#define ClearPageCompound(page) clear_bit(PG_compound, &(page)->flags)
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#ifdef CONFIG_SWAP
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#define PageSwapCache(page) test_bit(PG_swapcache, &(page)->flags)
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#define SetPageSwapCache(page) set_bit(PG_swapcache, &(page)->flags)
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#define ClearPageSwapCache(page) clear_bit(PG_swapcache, &(page)->flags)
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#else
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#define PageSwapCache(page) 0
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#endif
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#define PageUncached(page) test_bit(PG_uncached, &(page)->flags)
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#define SetPageUncached(page) set_bit(PG_uncached, &(page)->flags)
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#define ClearPageUncached(page) clear_bit(PG_uncached, &(page)->flags)
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struct page; /* forward declaration */
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int test_clear_page_dirty(struct page *page);
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int test_clear_page_writeback(struct page *page);
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int test_set_page_writeback(struct page *page);
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static inline void clear_page_dirty(struct page *page)
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{
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test_clear_page_dirty(page);
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}
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static inline void set_page_writeback(struct page *page)
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{
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test_set_page_writeback(page);
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}
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#endif /* PAGE_FLAGS_H */
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