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	 664beed019
			
		
	
	
		664beed019
		
	
	
	
	
		
			
			It looks like snd_xxx is not the only nopage to be using PageReserved as a way of holding a high-order page together: which no longer works, but is masked by our failure to free from VM_RESERVED areas. We cannot fix that bug without first substituting another way to hold the high-order page together, while farming out the 0-order pages from within it. That's just what PageCompound is designed for, but it's been kept under CONFIG_HUGETLB_PAGE. Remove the #ifdefs: which saves some space (out- of-line put_page), doesn't slow down what most needs to be fast (already using hugetlb), and unifies the way we handle high-order pages. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
		
			
				
	
	
		
			323 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			323 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Macros for manipulating and testing page->flags
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|  */
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| 
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| #ifndef PAGE_FLAGS_H
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| #define PAGE_FLAGS_H
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| 
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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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| /*
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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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| /*
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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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| 
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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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| 
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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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| 
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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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| 
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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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| /*
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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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| 	/*
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| /*
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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| #define PageCompound(page)	test_bit(PG_compound, &(page)->flags)
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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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| 
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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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| 
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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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| 
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| struct page;	/* forward declaration */
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| 
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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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| 
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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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| 
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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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| 
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| #endif	/* PAGE_FLAGS_H */
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