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

[Wu Fengguang]

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@xxxxxxxxxxxxxxxx>
---


--- 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. */

--
-
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