Commits
Ryusuke Konishi committed 53a2c3bdf41
nilfs2: improve execution time of NILFS_IOCTL_GET_CPINFO ioctl
The older a filesystem gets, the slower lscp command becomes. This is
because nilfs_cpfile_do_get_cpinfo() function meets more hole blocks
as the start offset of valid checkpoint numbers gets bigger.
This reduces the overhead by skipping hole blocks efficiently with
nilfs_mdt_find_block() helper.
A measurement result of this patch is as follows:
Before:
$ time lscp
CNO DATE TIME MODE FLG BLKCNT ICNT
5769303 2015-02-22 19:31:33 cp - 108 1
5769304 2015-02-22 19:38:54 cp - 108 1
real 0m0.182s
user 0m0.003s
sys 0m0.180s
After:
$ time lscp
CNO DATE TIME MODE FLG BLKCNT ICNT
5769303 2015-02-22 19:31:33 cp - 108 1
5769304 2015-02-22 19:38:54 cp - 108 1
real 0m0.003s
user 0m0.001s
sys 0m0.002s
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>