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authorYu Kuai <yukuai3@huawei.com>2024-05-09 20:37:17 +0800
committerJens Axboe <axboe@kernel.dk>2024-05-09 07:59:44 -0600
commit7be835694daebbb4adffbc461519081aa0cf28e1 (patch)
tree4f9903b5a99814958e317bf070d77a3d08da902f /block
parent99dc422335d8b2bd4d105797241d3e715bae90e9 (diff)
block: fix that util can be greater than 100%
util means the percentage that disk has IO, and theoretically it should not be greater than 100%. However, there is a gap for rq-based disk: io_ticks will be updated when rq is allocated, however, before such rq dispatch to driver, it will not be account as inflight from blk_mq_start_request() hence diskstats_show()/part_stat_show() will not update io_ticks. For example: 1) at t0, issue a new IO, rq is allocated, and blk_account_io_start() update io_ticks; 2) something is wrong with drivers, and the rq can't be dispatched; 3) at t0 + 10s, drivers recovers and rq is dispatched and done, io_ticks is updated; Then if user is using "iostat 1" to monitor "util", between t0 - t0+9s, util will be zero, and between t0+9s - t0+10s, util will be 1000%. Fix this problem by updating io_ticks from diskstats_show() and part_stat_show() if there are rq allocated. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Link: https://lore.kernel.org/r/20240509123717.3223892-3-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/genhd.c12
1 files changed, 2 insertions, 10 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 8f1163d2d171..7f39fbe60753 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -951,15 +951,10 @@ ssize_t part_stat_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct block_device *bdev = dev_to_bdev(dev);
- struct request_queue *q = bdev_get_queue(bdev);
struct disk_stats stat;
unsigned int inflight;
- if (queue_is_mq(q))
- inflight = blk_mq_in_flight(q, bdev);
- else
- inflight = part_in_flight(bdev);
-
+ inflight = part_in_flight(bdev);
if (inflight) {
part_stat_lock();
update_io_ticks(bdev, jiffies, true);
@@ -1256,11 +1251,8 @@ 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;
- if (queue_is_mq(gp->queue))
- inflight = blk_mq_in_flight(gp->queue, hd);
- else
- inflight = part_in_flight(hd);
+ inflight = part_in_flight(hd);
if (inflight) {
part_stat_lock();
update_io_ticks(hd, jiffies, true);