From 8b010acb3154b669e52f0eef4a6d925e3cc1db2f Mon Sep 17 00:00:00 2001 From: Wang Jianchao Date: Wed, 13 Sep 2023 09:38:01 +0800 Subject: 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 Signed-off-by: Wang Jianchao Signed-off-by: Chandan Babu R --- fs/xfs/xfs_log_recover.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/xfs/xfs_log_recover.c') 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))) { -- cgit v1.2.3