[PATCH 1/5] readahead: no RA_FLAG_EOF on single page file

Wu Fengguang
2006-06-09T08:11:24Z

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Dot not set RA_FLAG_EOF on single page files.

readahead_close() will be called if RA_FLAG_EOF is there on file close.
It detects readahead hit/miss, and adjust ra_expected_bytes correspondingly.
Single page files are uninteresting for it. Since near 40% desktop
files are <= 4k, this patch can reduce many useless readahead_close()
invocations.

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

--- linux-2.6.17-rc5-mm3.orig/mm/readahead.c
+++ linux-2.6.17-rc5-mm3/mm/readahead.c
@@ -1037,7 +1037,8 @@ static int ra_dispatch(struct file_ra_st
ra->readahead_index = eof_index;
if (ra->lookahead_index > eof_index)
ra->lookahead_index = eof_index;
- ra->flags |= RA_FLAG_EOF;
+ if (eof_index > 1)
+ ra->flags |= RA_FLAG_EOF;
}

/* Disable look-ahead for loopback file. */

--