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Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 324 |
1 files changed, 324 insertions, 0 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h new file mode 100644 index 000000000000..6b74fcf5bb63 --- /dev/null +++ b/include/linux/page-flags.h @@ -0,0 +1,324 @@ +/* + * 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_highmem 8 +#define PG_checked 9 /* kill me in 2.5.<early>. */ +#define PG_arch_1 10 +#define PG_reserved 11 + +#define PG_private 12 /* Has something at ->private */ +#define PG_writeback 13 /* Page is under writeback */ +#define PG_nosave 14 /* Used for system suspend/resume */ +#define PG_compound 15 /* Part of a compound page */ + +#define PG_swapcache 16 /* Swap page: swp_entry_t in private */ +#define PG_mappedtodisk 17 /* Has blocks allocated on-disk */ +#define PG_reclaim 18 /* To be reclaimed asap */ +#define PG_nosave_free 19 /* Free, should not be written */ +#define PG_uncached 20 /* Page has been mapped as uncached */ + +/* + * Global page accounting. One instance per CPU. Only unsigned longs are + * allowed. + */ +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 */ + 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_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_dma; + + unsigned long pgsteal_high; /* total highmem pages reclaimed */ + unsigned long pgsteal_normal; + unsigned long pgsteal_dma; + unsigned long pgscan_kswapd_high;/* total highmem pages scanned */ + unsigned long pgscan_kswapd_normal; + + unsigned long pgscan_kswapd_dma; + unsigned long pgscan_direct_high;/* total highmem pages scanned */ + unsigned long pgscan_direct_normal; + 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 */ +}; + +extern void get_page_state(struct page_state *ret); +extern void get_full_page_state(struct page_state *ret); +extern unsigned long __read_page_state(unsigned offset); +extern void __mod_page_state(unsigned offset, unsigned long delta); + +#define read_page_state(member) \ + __read_page_state(offsetof(struct page_state, member)) + +#define mod_page_state(member, delta) \ + __mod_page_state(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 mod_page_state_zone(zone, member, delta) \ + do { \ + 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 \ + offset = offsetof(struct page_state, member##_dma); \ + __mod_page_state(offset, (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 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) test_bit(PG_highmem, &(page)->flags) +#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) + +#ifdef CONFIG_HUGETLB_PAGE +#define PageCompound(page) test_bit(PG_compound, &(page)->flags) +#else +#define PageCompound(page) 0 +#endif +#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 */ |