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| author | Fengguang Wu <wfg@mail.ustc.edu.cn> | 2007-07-19 01:47:55 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-19 10:04:43 -0700 |
| commit | d77c2d7cc5126639a47d73300b40d461f2811a0f (patch) | |
| tree | d02b32ca92fde9a04be9bee0f0b7c8961479448c | |
| parent | 2ba2d00363975242dee9bb22cf798b487e3cd61e (diff) | |
| download | op-kernel-dev-d77c2d7cc5126639a47d73300b40d461f2811a0f.zip op-kernel-dev-d77c2d7cc5126639a47d73300b40d461f2811a0f.tar.gz | |
readahead: introduce PG_readahead
Introduce a new page flag: PG_readahead.
It acts as a look-ahead mark, which tells the page reader: Hey, it's time to
invoke the read-ahead logic. For the sake of I/O pipelining, don't wait until
it runs out of cached pages!
Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
Cc: Steven Pratt <slpratt@austin.ibm.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/page-flags.h | 5 | ||||
| -rw-r--r-- | mm/page_alloc.c | 2 |
2 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 731cd2a..709d92f 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -83,6 +83,7 @@ #define PG_private 11 /* If pagecache, has fs-private data */ #define PG_writeback 12 /* Page is under writeback */ +#define PG_readahead 13 /* Reminder to do async read-ahead */ #define PG_compound 14 /* Part of a compound page */ #define PG_swapcache 15 /* Swap page: swp_entry_t in private */ @@ -226,6 +227,10 @@ static inline void SetPageUptodate(struct page *page) #define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags) #define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags) +#define PageReadahead(page) test_bit(PG_readahead, &(page)->flags) +#define SetPageReadahead(page) set_bit(PG_readahead, &(page)->flags) +#define ClearPageReadahead(page) clear_bit(PG_readahead, &(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) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e2a10b9..2165be9 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -617,7 +617,7 @@ static int prep_new_page(struct page *page, int order, gfp_t gfp_flags) if (PageReserved(page)) return 1; - page->flags &= ~(1 << PG_uptodate | 1 << PG_error | + page->flags &= ~(1 << PG_uptodate | 1 << PG_error | 1 << PG_readahead | 1 << PG_referenced | 1 << PG_arch_1 | 1 << PG_owner_priv_1 | 1 << PG_mappedtodisk); set_page_private(page, 0); |
