[PATCH 7/9] readahead: convert splice invocations

[Fengguang Wu <wfg@mail.ustc.edu.cn>]

[-- Attachment #1: readahead-invocations-splice.patch --]
[-- Type: text/plain, Size: 1598 bytes --]

Convert splice reads to use on-demand readahead.

Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
---
 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);

--