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

From: zhangwensheng (E)
Date: Mon Feb 07 2022 - 21:13:02 EST


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 "