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.
Fixes: 5b18b5a73760 ("block: delete part_round_stats and switch to less precise counting")
Signed-off-by: Zhang Wensheng <[email protected]>
---
block/genhd.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
---
v2:
* add part_stat_lock() & part_stat_unlock() to protect update_io_ticks().
v1: https://www.spinics.net/lists/linux-block/msg78931.html
diff --git a/block/genhd.c b/block/genhd.c
index 626c8406f21a..781dc78f97d8 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -913,12 +913,17 @@ 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 "
@@ -1174,12 +1179,17 @@ 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 "
--
2.31.1
friendly ping...
在 2022/2/17 14:42, Zhang Wensheng 写道:
> 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.
>
> Fixes: 5b18b5a73760 ("block: delete part_round_stats and switch to less precise counting")
> Signed-off-by: Zhang Wensheng <[email protected]>
> ---
> block/genhd.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
> ---
> v2:
> * add part_stat_lock() & part_stat_unlock() to protect update_io_ticks().
> v1: https://www.spinics.net/lists/linux-block/msg78931.html
>
> diff --git a/block/genhd.c b/block/genhd.c
> index 626c8406f21a..781dc78f97d8 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -913,12 +913,17 @@ 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 "
> @@ -1174,12 +1179,17 @@ 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 "
Looks good,
Reviewed-by: Christoph Hellwig <[email protected]>
On Thu, 17 Feb 2022 14:42:47 +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: 86d7331299fda7634b11c1b7c911432679d525a5
Best regards,
--
Jens Axboe