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/* * 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) */ #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 */ /* * Global page accounting. One instance per CPU. Only unsigned longs are * allowed. * * - 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. */ 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 */ unsigned long nr_mapped; /* mapped into pagetables. * only modified from process context */ 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 */ unsigned long pgalloc_high; /* page allocations */ unsigned long pgalloc_normal; unsigned long pgalloc_dma32; unsigned long pgalloc_dma; 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) */ unsigned long pgrefill_high; /* inspected in refill_inactive_zone */ unsigned long pgrefill_normal; unsigned long pgrefill_dma32; unsigned long pgrefill_dma; unsigned long pgsteal_high; /* total highmem pages reclaimed */ unsigned long pgsteal_normal; unsigned long pgsteal_dma32; unsigned long pgsteal_dma; unsigned long pgscan_kswapd_high;/* total highmem pages scanned */ unsigned long pgscan_kswapd_normal; unsigned long pgscan_kswapd_dma32; unsigned long pgscan_kswapd_dma; unsigned long pgscan_direct_high;/* total highmem pages scanned */ unsigned long pgscan_direct_normal; unsigned long pgscan_direct_dma32; unsigned long pgscan_direct_dma; unsigned long pginodesteal; /* pages reclaimed via inode freeing */ 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 */ unsigned long nr_bounce; /* pages for bounce buffers */ }; extern void get_page_state(struct page_state *ret); extern void get_page_state_node(struct page_state *ret, int node); extern void get_full_page_state(struct page_state *ret); 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); #define read_page_state(member) \ read_page_state_offset(offsetof(struct page_state, member)) #define mod_page_state(member, delta) \ mod_page_state_offset(offsetof(struct page_state, member), (delta)) #define __mod_page_state(member, delta) \ __mod_page_state_offset(offsetof(struct page_state, member), (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 __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) \ ({ \ 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); \ 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)); \ } while (0) /* * 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) #define __ClearPageDirty(page) __clear_bit(PG_dirty, &(page)->flags) #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 #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_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 */