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| author | Wang Jianchao <jianchwa@outlook.com> | 2023-09-13 09:38:01 +0800 |
|---|---|---|
| committer | Chandan Babu R <chandanbabu@kernel.org> | 2023-09-13 10:38:20 +0530 |
| commit | 8b010acb3154b669e52f0eef4a6d925e3cc1db2f (patch) | |
| tree | b73e826dd0d30ed73ac6e5c864f3b31e2138f064 | |
| parent | 1155b12edbb5d79a5730e1d9348cf3d8b2107696 (diff) | |
| download | lwn-8b010acb3154b669e52f0eef4a6d925e3cc1db2f.tar.gz lwn-8b010acb3154b669e52f0eef4a6d925e3cc1db2f.zip | |
xfs: use roundup_pow_of_two instead of ffs during xlog_find_tail
In our production environment, we find that mounting a 500M /boot
which is umount cleanly needs ~6s. One cause is that ffs() is
used by xlog_write_log_records() to decide the buffer size. It
can cause a lot of small IO easily when xlog_clear_stale_blocks()
needs to wrap around the end of log area and log head block is
not power of two. Things are similar in xlog_find_verify_cycle().
The code is able to handed bigger buffer very well, we can use
roundup_pow_of_two() to replace ffs() directly to avoid small
and sychronous IOs.
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Wang Jianchao <wangjc136@midea.com>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
| -rw-r--r-- | fs/xfs/xfs_log_recover.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c index 82c81d20459d..13b94d2e605b 100644 --- a/fs/xfs/xfs_log_recover.c +++ b/fs/xfs/xfs_log_recover.c @@ -329,7 +329,7 @@ xlog_find_verify_cycle( * try a smaller size. We need to be able to read at least * a log sector, or we're out of luck. */ - bufblks = 1 << ffs(nbblks); + bufblks = roundup_pow_of_two(nbblks); while (bufblks > log->l_logBBsize) bufblks >>= 1; while (!(buffer = xlog_alloc_buffer(log, bufblks))) { @@ -1528,7 +1528,7 @@ xlog_write_log_records( * a smaller size. We need to be able to write at least a * log sector, or we're out of luck. */ - bufblks = 1 << ffs(blocks); + bufblks = roundup_pow_of_two(blocks); while (bufblks > log->l_logBBsize) bufblks >>= 1; while (!(buffer = xlog_alloc_buffer(log, bufblks))) { |