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authorMikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>2013-07-04 19:04:01 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-04 11:22:46 -0700
commit275f495dbe34300d793466a7d96c70f83fbae1bc (patch)
tree75785e0623188c52360f845419354b3b7cd67051 /fs/hpfs/super.c
parenta0c1b7596323a2323d5f5c7d2404af7b58a1ef4e (diff)
downloadlinux-275f495dbe34300d793466a7d96c70f83fbae1bc.tar.gz
hpfs: implement prefetch to improve performance
This patch implements prefetch to improve performance.  It helps mostly
when scanning the bitmaps to calculate free space.

Signed-off-by: Mikulas Patocka <mpatocka@artax.karlin.mff.cuni.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/hpfs/super.c')
-rw-r--r--fs/hpfs/super.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c
index 962e90c37aec..4334cda8dba1 100644
--- a/fs/hpfs/super.c
+++ b/fs/hpfs/super.c
@@ -121,7 +121,7 @@ unsigned hpfs_count_one_bitmap(struct super_block *s, secno secno)
 	unsigned long *bits;
 	unsigned count;
 
-	bits = hpfs_map_4sectors(s, secno, &qbh, 4);
+	bits = hpfs_map_4sectors(s, secno, &qbh, 0);
 	if (!bits)
 		return 0;
 	count = bitmap_weight(bits, 2048 * BITS_PER_BYTE);
@@ -134,8 +134,13 @@ static unsigned count_bitmaps(struct super_block *s)
 	unsigned n, count, n_bands;
 	n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
 	count = 0;
-	for (n = 0; n < n_bands; n++)
+	for (n = 0; n < COUNT_RD_AHEAD; n++) {
+		hpfs_prefetch_bitmap(s, n);
+	}
+	for (n = 0; n < n_bands; n++) {
+		hpfs_prefetch_bitmap(s, n + COUNT_RD_AHEAD);
 		count += hpfs_count_one_bitmap(s, le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[n]));
+	}
 	return count;
 }