Commit 7ec2ec68 authored by Zhang Wensheng's avatar Zhang Wensheng Committed by Zheng Zengkai
Browse files

block: update io_ticks when io hang 

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4STNX?from=project-issue


CVE: NA

--------------------------------

When the inflight IOs are slow and no new IOs are issued, we expect
iostat could manifest the IO hang problem. However after
commit 5b18b5a7 ("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: 5b18b5a7 ("block: delete part_round_stats and switch to less precise counting")
Signed-off-by: default avatarZhang Wensheng <zhangwensheng5@huawei.com>
Reviewed-by: default avatarHou Tao <houtao1@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 0c093ccd

block/blk-core.c

+1 −1
Original line number Diff line number Diff line
@@ -1249,7 +1249,7 @@ unsigned int blk_rq_err_bytes(const struct request *rq) 
}

EXPORT_SYMBOL_GPL(blk_rq_err_bytes);



static void update_io_ticks(struct hd_struct *part, unsigned long now, bool end)

void update_io_ticks(struct hd_struct *part, unsigned long now, bool end)

{

	unsigned long stamp;

again:

block/blk.h

+2 −0
Original line number Diff line number Diff line
@@ -255,6 +255,8 @@ static inline bool blk_do_io_stat(struct request *rq) 
	return rq->rq_disk && (rq->rq_flags & RQF_IO_STAT);

}



void update_io_ticks(struct hd_struct *part, unsigned long now, bool end);



static inline void req_set_nomerge(struct request_queue *q, struct request *req)

{

	req->cmd_flags |= REQ_NOMERGE;

block/genhd.c

+12 −2
Original line number Diff line number Diff line
@@ -1301,12 +1301,17 @@ ssize_t part_stat_show(struct device *dev, 
	struct disk_stats stat;

	unsigned int inflight;



	part_stat_read_all(p, &stat);

	if (queue_is_mq(q))

		inflight = blk_mq_in_flight(q, p);

	else

		inflight = part_in_flight(p);



	if (inflight) {

		part_stat_lock();

		update_io_ticks(p, jiffies, true);

		part_stat_unlock();

	}

	part_stat_read_all(p, &stat);

	return sprintf(buf,

		"%8lu %8lu %8llu %8u "

		"%8lu %8lu %8llu %8u "
@@ -1623,12 +1628,17 @@ static int diskstats_show(struct seq_file *seqf, void *v) 


	disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);

	while ((hd = disk_part_iter_next(&piter))) {

		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 %s "

			   "%lu %lu %lu %u "

			   "%lu %lu %lu %u "