| Message ID | 20220125091938.1799001-1-zhangwensheng5@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [-next] block: update io_ticks when io hang | expand |
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@huawei.com> >> --- >> 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 "
friendly ping... 在 2022/2/8 10:12, zhangwensheng (E) 写道: > 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@huawei.com> >>> --- >>> 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 "
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,
On 2/16/22 8:07 PM, zhangwensheng (E) wrote: > hi, Jens: > > I am sorry that there are some problems with the patch below: > > > @@ -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 " > > It shoule use part_stat_lock() & part_stat_unlock() to protect update_io_ticks(), > > because it operates on per-cpu variables. And I will fix it in V2. I'll drop it, please resend a fixed and tested one.
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 "
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@huawei.com> --- block/genhd.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)