kernel_optimize_test/fs
Karsten Wiese f3ef6f63e5 [PATCH] Speedup FAT filesystem directory reads
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

This speeds up directory reads for large FAT partitions, if the buffercache
has to be filled from the drive. Following values were taken from:

        $ time find path_to_freshly_mounted_fat > /dev/null

on an otherwise idle system.

FAT with 16KB Clusters on IDE attached drive:   Factor  2
FAT with 32KB Clusters on USB2 attached drive:  Factor 10 (!)
Its less than 1/10 slower, if the buffercache is uptodate.

The patch introduces the new function fat_dir_readahead().

fat_dir_readahead() calls sb_breadahead() to readahead a whole cluster,
if the requested sector is the first one in a cluster.
It is usefull to do this, because on FAT directories occupy whole
clusters, with the exception of FAT12/FAT16 root dirs.

Readahead is only done, if the cluster's first sector is not uptodate
to avoid overhead, when the buffer cache is already uptodate.
Note that under memory pressure, the maximal byte count wasted
(read: has to be red from disk twice) is 1 cluster's size.  Thats 64KB.

fat_dir_readahead() is called from fat__get_entry().

There is also an unrelated cleanup at one spot:

        if (bh)
                brelse(bh);

is replaced with:

        brelse(bh);

brelse() can handle NULL pointer arguments by itself.

Signed-off-by: Karsten Wiese <annabellesgarden@yahoo.de>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07 16:57:26 -07:00
..
adfs [ARM] fs/adfs/adfs.h: "extern inline" doesn't make sense 2005-08-20 17:20:28 +01:00
affs
afs [PATCH] Fix up symlink function pointers 2005-08-19 18:08:21 -07:00
autofs Fix nasty ncpfs symlink handling bug. 2005-08-19 18:02:56 -07:00
autofs4 [PATCH] Fix up symlink function pointers 2005-08-19 18:08:21 -07:00
befs befs: fix up missed follow_link declaration change 2005-08-20 13:20:01 -07:00
bfs
cifs [PATCH] Fix oops in fs/locks.c on close of file with pending locks 2005-08-26 16:05:35 -07:00
coda [PATCH] class: convert the remaining class_simple users in the kernel to usee the new class api 2005-06-20 15:15:11 -07:00
cramfs
debugfs [PATCH] remove duplicate get_dentry functions in various places 2005-06-23 09:45:20 -07:00
devfs [PATCH] Fix up symlink function pointers 2005-08-19 18:08:21 -07:00
devpts [PATCH] Generic VFS fallback for security xattrs 2005-09-05 00:05:52 -07:00
efs
exportfs
ext2 [PATCH] disk quotas fail when /etc/mtab is symlinked to /proc/mounts 2005-09-07 16:57:23 -07:00
ext3 [PATCH] disk quotas fail when /etc/mtab is symlinked to /proc/mounts 2005-09-07 16:57:23 -07:00
fat [PATCH] Speedup FAT filesystem directory reads 2005-09-07 16:57:26 -07:00
freevxfs [PATCH] freevxfs: fix breakage introduced by symlink fixes 2005-08-20 14:30:50 -07:00
hfs [PATCH] hfs: don't reference missing page 2005-08-01 21:38:00 -07:00
hfsplus [PATCH] hfs: don't reference missing page 2005-08-01 21:38:00 -07:00
hostfs [PATCH] uml: implement hostfs syncing 2005-07-28 21:46:05 -07:00
hpfs
hppfs [PATCH] hppfs: fix symlink error path 2005-08-26 11:39:19 -07:00
hugetlbfs [PATCH] Avoiding mmap fragmentation 2005-06-21 18:46:16 -07:00
isofs Check input buffer size in zisofs 2005-08-06 09:42:06 -07:00
jbd [PATCH] fs/jbd/: cleanups 2005-09-07 16:57:19 -07:00
jffs [PATCH] Fix missing refrigerator invocation in jffs2 2005-07-27 16:25:49 -07:00
jffs2 [PATCH] Fix up symlink function pointers 2005-08-19 18:08:21 -07:00
jfs [PATCH] disk quotas fail when /etc/mtab is symlinked to /proc/mounts 2005-09-07 16:57:23 -07:00
lockd [PATCH] NFS: procfs/sysctl interfaces for lockd do not work on x86_64 2005-07-13 11:25:24 -07:00
minix
msdos
ncpfs [PATCH] fs/ncpfs/: remove unused #ifdef USE_OLD_SLOW_DIRECTORY_LISTING code 2005-06-25 16:25:04 -07:00
nfs [PATCH] NFSv4: unbalanced BKL in nfs_atomic_lookup() 2005-08-19 18:44:56 -07:00
nfs_common [PATCH] NFS: Ensure ACL xdr code doesn't overflow. 2005-08-16 08:52:11 -07:00
nfsd [PATCH] sunrpc: cache_register can use wrong module reference 2005-09-07 16:57:25 -07:00
nls [PATCH] make some things static 2005-05-05 16:36:47 -07:00
ntfs NTFS: Complete the previous fix for the unset device when mapping buffers 2005-08-16 19:42:56 +01:00
openpromfs
partitions [PATCH] small partitions/msdos cleanups 2005-06-25 16:24:59 -07:00
proc [PATCH] add /proc/pid/smaps 2005-09-05 00:05:49 -07:00
qnx4 [PATCH] fs/qnx4/*: fix sparse warnings 2005-06-24 14:14:24 -07:00
ramfs
reiserfs [PATCH] reiserfs+acl+quota deadlock fix 2005-08-18 12:53:57 -07:00
relayfs [PATCH] relayfs 2005-09-07 16:57:18 -07:00
romfs
smbfs [TCP]: Move the tcp sock states to net/tcp_states.h 2005-08-29 15:41:54 -07:00
sysfs [PATCH] Fix oops in sysfs_hash_and_remove_file() 2005-08-26 19:37:13 -07:00
sysv [PATCH] Fix up symlink function pointers 2005-08-19 18:08:21 -07:00
udf [PATCH] udf_find_entry() cleanup 2005-06-30 08:45:11 -07:00
ufs [PATCH] Fix up symlink function pointers 2005-08-19 18:08:21 -07:00
umsdos
vfat
xfs [PATCH] Fix up symlink function pointers 2005-08-19 18:08:21 -07:00
aio.c [PATCH] uml: fixes performance regression in activate_mm and thus exec() 2005-09-05 00:06:21 -07:00
attr.c [PATCH] inotify 2005-07-12 20:38:38 -07:00
bad_inode.c [PATCH] make some things static 2005-05-05 16:36:47 -07:00
binfmt_aout.c [PATCH] Avoiding mmap fragmentation 2005-06-21 18:46:16 -07:00
binfmt_elf_fdpic.c
binfmt_elf.c [PATCH] Avoiding mmap fragmentation 2005-06-21 18:46:16 -07:00
binfmt_em86.c
binfmt_flat.c [PATCH] uclinux: use MAP_PRIVATE when mmaping code regions in flat binary loader 2005-09-02 00:57:31 -07:00
binfmt_misc.c
binfmt_script.c
binfmt_som.c
bio.c [PATCH] kill bio->bi_set 2005-09-07 16:57:20 -07:00
block_dev.c [PATCH] block: add unlocked_ioctl support for block devices 2005-06-23 09:45:32 -07:00
buffer.c [PATCH] page_uptodate locking scalability 2005-07-07 18:23:45 -07:00
char_dev.c [PATCH] cdev: cdev_put oops 2005-07-12 16:01:02 -07:00
compat_ioctl.c
compat.c [PATCH] remove register_ioctl32_conversion and unregister_ioctl32_conversion 2005-09-07 16:57:20 -07:00
dcache.c [PATCH] fsnotify_name/inoderemove 2005-08-08 11:53:47 -07:00
dcookies.c [PATCH] dcookies.c: use proper refcounting functions 2005-07-07 18:23:52 -07:00
direct-io.c [PATCH] pass iocb to dio_iodone_t 2005-06-24 00:05:19 -07:00
dnotify.c
dquot.c [PATCH] list_for_each_entry: fs-dquot.c 2005-06-25 16:25:11 -07:00
eventpoll.c [PATCH] Remove eventpoll macro obfuscation 2005-06-23 09:45:30 -07:00
exec.c [PATCH] reset real_timer target on exec leader change 2005-07-12 16:01:01 -07:00
fcntl.c [PATCH] stale POSIX lock handling 2005-07-27 16:26:06 -07:00
fifo.c
file_table.c [PATCH] inotify 2005-07-12 20:38:38 -07:00
file.c
filesystems.c
fs-writeback.c [PATCH] O(1) sb list traversing on syncs 2005-06-23 09:45:27 -07:00
inode.c [PATCH] Fix soft lockup due to NTFS: VFS part and explanation 2005-07-13 11:25:24 -07:00
inotify.c [PATCH] inotify speedup 2005-09-07 16:57:19 -07:00
ioctl.c
ioprio.c Don't allow normal users to set idle IO priority 2005-08-20 18:51:29 -07:00
Kconfig [PATCH] relayfs 2005-09-07 16:57:18 -07:00
Kconfig.binfmt
libfs.c [PATCH] fix fsync(dir) return value for ram-based filesystems 2005-06-25 16:24:38 -07:00
locks.c [PATCH] stale POSIX lock handling 2005-07-27 16:26:06 -07:00
Makefile [PATCH] relayfs 2005-09-07 16:57:18 -07:00
mbcache.c [PATCH] mbcache: Remove unused mb_cache_shrink parameter 2005-07-27 16:26:07 -07:00
mpage.c [PATCH] mpage_end_io_write() I/O error handling fix 2005-06-04 17:12:59 -07:00
namei.c Fix nasty ncpfs symlink handling bug. 2005-08-19 18:02:56 -07:00
namespace.c [PATCH] namespace.c: fix bind mount from foreign namespace 2005-08-07 10:00:38 -07:00
nfsctl.c
open.c [PATCH] inotify 2005-07-12 20:38:38 -07:00
pipe.c
posix_acl.c
quota_v1.c
quota_v2.c
quota.c [PATCH] O(1) sb list traversing on syncs 2005-06-23 09:45:27 -07:00
read_write.c [PATCH] inotify 2005-07-12 20:38:38 -07:00
readdir.c
select.c [PATCH] make some things static 2005-05-05 16:36:47 -07:00
seq_file.c [PATCH] DocBook: fix some descriptions 2005-05-01 08:59:26 -07:00
stat.c
super.c [PATCH] set mnt_namespace in the correct place 2005-07-07 18:23:52 -07:00
xattr_acl.c
xattr.c [PATCH] Generic VFS fallback for security xattrs 2005-09-05 00:05:52 -07:00