The patch titled
Subject: nilfs2: improve execution time of NILFS_IOCTL_GET_CPINFO ioctl
has been added to the -mm tree. Its filename is
nilfs2-improve-execution-time-of-nilfs_ioctl_get_cpinfo-ioctl.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/nilfs2-improve-execution-time-of-nilfs_ioctl_get_cpinfo-ioctl.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/nilfs2-improve-execution-time-of-nilfs_ioctl_get_cpinfo-ioctl.patch
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------------------------------------------------------
From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/nilfs2/cpfile.c | 58 ++++++++++++++++++++++++++++++++++++++-----
1 file changed, 52 insertions(+), 6 deletions(-)
diff -puN fs/nilfs2/cpfile.c~nilfs2-improve-execution-time-of-nilfs_ioctl_get_cpinfo-ioctl fs/nilfs2/cpfile.c
--- a/fs/nilfs2/cpfile.c~nilfs2-improve-execution-time-of-nilfs_ioctl_get_cpinfo-ioctl
+++ a/fs/nilfs2/cpfile.c
@@ -53,6 +53,13 @@ nilfs_cpfile_get_offset(const struct ino
return do_div(tcno, nilfs_cpfile_checkpoints_per_block(cpfile));
}
+static __u64 nilfs_cpfile_first_checkpoint_in_block(const struct inode *cpfile,
+ unsigned long blkoff)
+{
+ return (__u64)nilfs_cpfile_checkpoints_per_block(cpfile) * blkoff
+ + 1 - NILFS_MDT(cpfile)->mi_first_entry_offset;
+}
+
static unsigned long
nilfs_cpfile_checkpoints_in_block(const struct inode *cpfile,
__u64 curr,
@@ -146,6 +153,44 @@ static inline int nilfs_cpfile_get_check
create, nilfs_cpfile_block_init, bhp);
}
+/**
+ * nilfs_cpfile_find_checkpoint_block - find and get a buffer on cpfile
+ * @cpfile: inode of cpfile
+ * @start_cno: start checkpoint number (inclusive)
+ * @end_cno: end checkpoint number (inclusive)
+ * @cnop: place to store the next checkpoint number
+ * @bhp: place to store a pointer to buffer_head struct
+ *
+ * Return Value: On success, it returns 0. On error, the following negative
+ * error code is returned.
+ *
+ * %-ENOMEM - Insufficient memory available.
+ *
+ * %-EIO - I/O error
+ *
+ * %-ENOENT - no block exists in the range.
+ */
+static int nilfs_cpfile_find_checkpoint_block(struct inode *cpfile,
+ __u64 start_cno, __u64 end_cno,
+ __u64 *cnop,
+ struct buffer_head **bhp)
+{
+ unsigned long start, end, blkoff;
+ int ret;
+
+ if (unlikely(start_cno > end_cno))
+ return -ENOENT;
+
+ start = nilfs_cpfile_get_blkoff(cpfile, start_cno);
+ end = nilfs_cpfile_get_blkoff(cpfile, end_cno);
+
+ ret = nilfs_mdt_find_block(cpfile, start, end, &blkoff, bhp);
+ if (!ret)
+ *cnop = (blkoff == start) ? start_cno :
+ nilfs_cpfile_first_checkpoint_in_block(cpfile, blkoff);
+ return ret;
+}
+
static inline int nilfs_cpfile_delete_checkpoint_block(struct inode *cpfile,
__u64 cno)
{
@@ -403,14 +448,15 @@ static ssize_t nilfs_cpfile_do_get_cpinf
return -ENOENT; /* checkpoint number 0 is invalid */
down_read(&NILFS_MDT(cpfile)->mi_sem);
- for (n = 0; cno < cur_cno && n < nci; cno += ncps) {
- ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno);
- ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
+ for (n = 0; n < nci; cno += ncps) {
+ ret = nilfs_cpfile_find_checkpoint_block(
+ cpfile, cno, cur_cno - 1, &cno, &bh);
if (ret < 0) {
- if (ret != -ENOENT)
- goto out;
- continue; /* skip hole */
+ if (likely(ret == -ENOENT))
+ break;
+ goto out;
}
+ ncps = nilfs_cpfile_checkpoints_in_block(cpfile, cno, cur_cno);
kaddr = kmap_atomic(bh->b_page);
cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
_
Patches currently in -mm which might be from konishi.ryusuke@xxxxxxxxxxxxx are
nilfs2-do-not-use-async-write-flag-for-segment-summary-buffers.patch
nilfs2-use-set_mask_bits-for-operations-on-buffer-state-bitmap.patch
nilfs2-use-bgl_lock_ptr.patch
nilfs2-unify-type-of-key-arguments-in-bmap-interface.patch
nilfs2-add-bmap-function-to-seek-a-valid-key.patch
nilfs2-add-helper-to-find-existent-block-on-metadata-file.patch
nilfs2-improve-execution-time-of-nilfs_ioctl_get_cpinfo-ioctl.patch
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