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>
diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c
index 962e90c..4334cda 100644
--- a/fs/hpfs/super.c
+++ b/fs/hpfs/super.c
@@ -121,7 +121,7 @@
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 @@
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;
}