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>

1 files changed, 5 insertions, 2 deletions

diff --git a/fs/hpfs/hpfs_fn.h b/fs/hpfs/hpfs_fn.h
index b7ae286646b5..1b398636e990 100644
--- a/fs/hpfs/hpfs_fn.h
+++ b/fs/hpfs/hpfs_fn.h
@@ -27,8 +27,9 @@
 #define ALLOC_FWD_MAX   128
 #define ALLOC_M         1
 #define FNODE_RD_AHEAD  16
-#define ANODE_RD_AHEAD  16
-#define DNODE_RD_AHEAD  4
+#define ANODE_RD_AHEAD  0
+#define DNODE_RD_AHEAD  72
+#define COUNT_RD_AHEAD  62
 
 #define FREE_DNODES_ADD 58
 #define FREE_DNODES_DEL 29
@@ -207,6 +208,7 @@ void hpfs_remove_fnode(struct super_block *, fnode_secno fno);
 
 /* buffer.c */
 
+void hpfs_prefetch_sectors(struct super_block *, unsigned, int);
 void *hpfs_map_sector(struct super_block *, unsigned, struct buffer_head **, int);
 void *hpfs_get_sector(struct super_block *, unsigned, struct buffer_head **);
 void *hpfs_map_4sectors(struct super_block *, unsigned, struct quad_buffer_head *, int);
@@ -271,6 +273,7 @@ void hpfs_evict_inode(struct inode *);
 
 __le32 *hpfs_map_dnode_bitmap(struct super_block *, struct quad_buffer_head *);
 __le32 *hpfs_map_bitmap(struct super_block *, unsigned, struct quad_buffer_head *, char *);
+void hpfs_prefetch_bitmap(struct super_block *, unsigned);
 unsigned char *hpfs_load_code_page(struct super_block *, secno);
 __le32 *hpfs_load_bitmap_directory(struct super_block *, secno bmp);
 struct fnode *hpfs_map_fnode(struct super_block *s, ino_t, struct buffer_head **);