On Tue, 25 Jan 2022 17:19:38 +0800, Zhang Wensheng wrote:

When the inflight IOs are slow and no new IOs are issued, we expect
iostat could manifest the IO hang problem. However after
commit 5b18b5a73760 ("block: delete part_round_stats and switch to less
precise counting"), io_tick and time_in_queue will not be updated until
the end of IO, and the avgqu-sz and %util columns of iostat will be zero.

Because it has using stat.nsecs accumulation to express time_in_queue
which is not suitable to change, and may %util will express the status
better when io hang occur. To fix io_ticks, we use update_io_ticks and
inflight to update io_ticks when diskstats_show and part_stat_show
been called.

[...]

Applied, thanks!

[1/1] block: update io_ticks when io hang
      commit: 62847731488f59971413484005a7fb2772cb9249

Best regards,
-- 
Jens Axboe