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| author | Fengguang Wu <wfg@mail.ustc.edu.cn> | 2007-07-19 01:47:59 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-19 10:04:44 -0700 |
| commit | 5ce1110b92b31d079aa443e967f43a2294e01194 (patch) | |
| tree | eff95b4c8ede07d0777ca68a30d686d1acbb5c73 /mm/readahead.c | |
| parent | f615bfca468c9b80ed2d09be5fdbaf470a32c045 (diff) | |
| download | lwn-5ce1110b92b31d079aa443e967f43a2294e01194.tar.gz lwn-5ce1110b92b31d079aa443e967f43a2294e01194.zip | |
readahead: data structure and routines
Extend struct file_ra_state to support the on-demand readahead logic. Also
define some helpers for it.
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>
Diffstat (limited to 'mm/readahead.c')
| -rw-r--r-- | mm/readahead.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/mm/readahead.c b/mm/readahead.c index 7f9bf588c936..072ce8f8357d 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -592,3 +592,22 @@ unsigned long max_sane_readahead(unsigned long nr) return min(nr, (node_page_state(numa_node_id(), NR_INACTIVE) + node_page_state(numa_node_id(), NR_FREE_PAGES)) / 2); } + +/* + * Submit IO for the read-ahead request in file_ra_state. + */ +unsigned long ra_submit(struct file_ra_state *ra, + struct address_space *mapping, struct file *filp) +{ + unsigned long ra_size; + unsigned long la_size; + int actual; + + ra_size = ra_readahead_size(ra); + la_size = ra_lookahead_size(ra); + actual = __do_page_cache_readahead(mapping, filp, + ra->ra_index, ra_size, la_size); + + return actual; +} +EXPORT_SYMBOL_GPL(ra_submit); |