diff options
Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 84 |
1 files changed, 76 insertions, 8 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 9ae7a8009ead..aeba6b4f74ac 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -6,6 +6,70 @@ #define PAGE_FLAGS_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_dontuse 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 + * pagemap_lru_lock, and *NOT* by the usual PG_locked_dontuse bit! + * + * PG_skip is used on sparc/sparc64 architectures to "skip" certain parts of + * the address space. + * + * 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_dontuse 0 /* Page is locked. Don't touch. */ +#define PG_error 1 +#define PG_referenced 2 +#define PG_uptodate 3 + +#define PG_dirty_dontuse 4 +#define PG_lru 5 +#define PG_active 6 +#define PG_slab 7 /* slab debug (Suparna wants this) */ + +#define PG_skip 8 /* kill me now: obsolete */ +#define PG_highmem 9 +#define PG_checked 10 /* kill me in 2.5.<early>. */ +#define PG_arch_1 11 + +#define PG_reserved 12 +#define PG_launder 13 /* written out by VM pressure.. */ +#define PG_private 14 /* Has something at ->private */ + +/* * Global page accounting. One instance per CPU. */ extern struct page_state { @@ -30,7 +94,6 @@ extern void get_page_state(struct page_state *ret); /* * Manipulation of page state flags */ -#define UnlockPage(page) unlock_page(page) #define PageLocked(page) test_bit(PG_locked_dontuse, &(page)->flags) #define SetPageLocked(page) \ do { \ @@ -38,8 +101,7 @@ extern void get_page_state(struct page_state *ret); &(page)->flags)) \ inc_page_state(nr_locked); \ } while (0) -#define LockPage(page) SetPageLocked(page) /* grr. kill me */ -#define TryLockPage(page) \ +#define TestSetPageLocked(page) \ ({ \ int ret; \ ret = test_and_set_bit(PG_locked_dontuse, \ @@ -71,9 +133,9 @@ extern void get_page_state(struct page_state *ret); #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 PageTestandClearReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags) +#define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags) -#define Page_Uptodate(page) test_bit(PG_uptodate, &(page)->flags) +#define PageUptodate(page) test_bit(PG_uptodate, &(page)->flags) #define SetPageUptodate(page) set_bit(PG_uptodate, &(page)->flags) #define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags) @@ -118,8 +180,8 @@ extern void get_page_state(struct page_state *ret); #define ClearPageActive(page) clear_bit(PG_active, &(page)->flags) #define PageSlab(page) test_bit(PG_slab, &(page)->flags) -#define PageSetSlab(page) set_bit(PG_slab, &(page)->flags) -#define PageClearSlab(page) clear_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) test_bit(PG_highmem, &(page)->flags) @@ -133,7 +195,6 @@ extern void get_page_state(struct page_state *ret); #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 __SetPageReserved(page) __set_bit(PG_reserved, &(page)->flags) #define PageLaunder(page) test_bit(PG_launder, &(page)->flags) #define SetPageLaunder(page) set_bit(PG_launder, &(page)->flags) @@ -142,4 +203,11 @@ extern void get_page_state(struct page_state *ret); #define ClearPagePrivate(page) clear_bit(PG_private, &(page)->flags) #define PagePrivate(page) test_bit(PG_private, &(page)->flags) +/* + * The PageSwapCache predicate doesn't use a PG_flag at this time, + * but it may again do so one day. + */ +extern struct address_space swapper_space; +#define PageSwapCache(page) ((page)->mapping == &swapper_space) + #endif /* PAGE_FLAGS_H */ |