diff options
| author | Boris Burkov <boris@bur.io> | 2025-05-08 17:54:41 -0700 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2025-07-21 23:53:26 +0200 |
| commit | c7f04fbc98dcf81723bb2fdc65d905a38fc38f3c (patch) | |
| tree | adf724daab74131bc29d39aa1477d9744fa8ba32 /fs/btrfs/sysfs.c | |
| parent | 46d549928cc93f9b08fd66d0ff7778e800bb17f3 (diff) | |
btrfs: sysfs: track current commit duration in commit_stats
When debugging/detecting outlier commit stalls, having an indicator that
we are currently in a long commit critical section can be very useful.
Extend the commit_stats sysfs file to also include the current commit
critical section duration.
Since this requires storing the last commit start time, use that rather
than a separate stack variable for storing the finished commit durations
as well.
This also requires slightly moving up the timing of the stats updating
to *inside* the critical section to avoid the transaction T+1 setting
the critical_section_start_time to 0 before transaction T can update its
stats, which would trigger the new ASSERT. This is an improvement in and
of itself, as it makes the stats more accurately represent the true
critical section time. It may be yet better to pull the stats up to where
start_transaction gets unblocked, rather than the next commit, but this
seems like a good enough place as well.
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/sysfs.c')
| -rw-r--r-- | fs/btrfs/sysfs.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index 5d93d9dd2c12..04715201c643 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -1138,13 +1138,21 @@ static ssize_t btrfs_commit_stats_show(struct kobject *kobj, struct kobj_attribute *a, char *buf) { struct btrfs_fs_info *fs_info = to_fs_info(kobj); + u64 now = ktime_get_ns(); + u64 start_time = fs_info->commit_stats.critical_section_start_time; + u64 pending = 0; + + if (start_time) + pending = now - start_time; return sysfs_emit(buf, "commits %llu\n" + "cur_commit_ms %llu\n" "last_commit_ms %llu\n" "max_commit_ms %llu\n" "total_commit_ms %llu\n", fs_info->commit_stats.commit_count, + div_u64(pending, NSEC_PER_MSEC), div_u64(fs_info->commit_stats.last_commit_dur, NSEC_PER_MSEC), div_u64(fs_info->commit_stats.max_commit_dur, NSEC_PER_MSEC), div_u64(fs_info->commit_stats.total_commit_dur, NSEC_PER_MSEC)); |