Commit 86d73312 authored Feb 17, 2022 by Zhang Wensheng Committed by Jens Axboe Feb 22, 2022

block: update io_ticks when io hang

When the inflight IOs are slow and no new IOs are issued, we expect
iostat could manifest the IO hang problem. However after
commit 5b18b5a7 ("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.

Fixes: 5b18b5a7 ("block: delete part_round_stats and switch to less precise counting")
Signed-off-by: Zhang Wensheng <zhangwensheng5@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220217064247.4041435-1-zhangwensheng5@huawei.com

Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 8410f709

block/genhd.c

+12 −2

Original line number	Diff line number	Diff line
		@@ -919,12 +919,17 @@ ssize_t part_stat_show(struct device *dev,
		struct disk_stats stat;
		unsigned int inflight;

		part_stat_read_all(bdev, &stat);
		if (queue_is_mq(q))
		inflight = blk_mq_in_flight(q, bdev);
		else
		inflight = part_in_flight(bdev);

		if (inflight) {
		part_stat_lock();
		update_io_ticks(bdev, jiffies, true);
		part_stat_unlock();
		}
		part_stat_read_all(bdev, &stat);
		return sprintf(buf,
		"%8lu %8lu %8llu %8u "
		"%8lu %8lu %8llu %8u "
		@@ -1184,12 +1189,17 @@ static int diskstats_show(struct seq_file seqf, void v)
		xa_for_each(&gp->part_tbl, idx, hd) {
		if (bdev_is_partition(hd) && !bdev_nr_sectors(hd))
		continue;
		part_stat_read_all(hd, &stat);
		if (queue_is_mq(gp->queue))
		inflight = blk_mq_in_flight(gp->queue, hd);
		else
		inflight = part_in_flight(hd);

		if (inflight) {
		part_stat_lock();
		update_io_ticks(hd, jiffies, true);
		part_stat_unlock();
		}
		part_stat_read_all(hd, &stat);
		seq_printf(seqf, "%4d %7d %pg "
		"%lu %lu %lu %u "
		"%lu %lu %lu %u "