Re: [PATCH -next] block: update io_ticks when io hang

[zhangwensheng (E)]

friendly ping...

在 2022/1/28 14:22, zhangwensheng (E) 写道:
> friendly ping...
>
> 在 2022/1/25 17:19, 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 <zhangwensheng5@xxxxxxxxxx>
> > ---
> >   block/genhd.c | 8 ++++++--
> >   1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/block/genhd.c b/block/genhd.c
> > index 626c8406f21a..df0656ffb4ad 100644
> > --- a/block/genhd.c
> > +++ b/block/genhd.c
> > @@ -913,12 +913,14 @@ 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)
> > +        update_io_ticks(bdev, jiffies, true);
> > +    part_stat_read_all(bdev, &stat);
> >       return sprintf(buf,
> >           "%8lu %8lu %8llu %8u "
> >           "%8lu %8lu %8llu %8u "
> > @@ -1174,12 +1176,14 @@ 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)
> > +            update_io_ticks(hd, jiffies, true);
> > +        part_stat_read_all(hd, &stat);
> >           seq_printf(seqf, "%4d %7d %pg "
> >                  "%lu %lu %lu %u "
> >                  "%lu %lu %lu %u "