2007-05-16 22:50:50

by Wu Fengguang

[permalink] [raw]
Subject: [PATCH 7/9] readahead: convert splice invocations

Convert splice reads to use on-demand readahead.

Signed-off-by: Fengguang Wu <[email protected]>
---
fs/splice.c | 18 +++++++-----------
1 file changed, 7 insertions(+), 11 deletions(-)

--- linux-2.6.22-rc1-mm1.orig/fs/splice.c
+++ linux-2.6.22-rc1-mm1/fs/splice.c
@@ -289,12 +289,6 @@ __generic_file_splice_read(struct file *
nr_pages = PIPE_BUFFERS;

/*
- * Don't try to 2nd guess the read-ahead logic, call into
- * page_cache_readahead() like the page cache reads would do.
- */
- page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages);
-
- /*
* Now fill in the holes:
*/
error = 0;
@@ -317,11 +311,8 @@ __generic_file_splice_read(struct file *
*/
page = find_get_page(mapping, index);
if (!page) {
- /*
- * Make sure the read-ahead engine is notified
- * about this failure.
- */
- handle_ra_miss(mapping, &in->f_ra, index);
+ page_cache_readahead_ondemand(mapping, &in->f_ra, in,
+ NULL, index, nr_pages - spd.nr_pages);

/*
* page didn't exist, allocate one.
@@ -368,6 +359,10 @@ __generic_file_splice_read(struct file *
this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff);
page = pages[page_nr];

+ if (PageReadahead(page))
+ page_cache_readahead_ondemand(mapping, &in->f_ra, in,
+ page, index, nr_pages - page_nr);
+
/*
* If the page isn't uptodate, we may need to start io on it
*/
@@ -456,6 +451,7 @@ fill_it:
*/
while (page_nr < nr_pages)
page_cache_release(pages[page_nr++]);
+ in->f_ra.prev_index = index;

if (spd.nr_pages)
return splice_to_pipe(pipe, &spd);

--