diff mbox series

blk-iolatency: only account submitted bios

Message ID 20190523201018.49615-1-dennis@kernel.org (mailing list archive)
State New, archived
Headers show
Series blk-iolatency: only account submitted bios | expand

Commit Message

Dennis Zhou May 23, 2019, 8:10 p.m. UTC
As is, iolatency recognizes done_bio and cleanup as ending paths. If a
request is marked REQ_NOWAIT and fails to get a request, the bio is
cleaned up via rq_qos_cleanup() and ended in bio_wouldblock_error().
This results in underflowing the inflight counter. Fix this by only
accounting bios that were actually submitted.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Cc: Josef Bacik <josef@toxicpanda.com>
---
 block/blk-iolatency.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Dennis Zhou June 15, 2019, 4:51 p.m. UTC | #1
Hi Jens,

On Thu, May 23, 2019 at 04:10:18PM -0400, Dennis Zhou wrote:
> As is, iolatency recognizes done_bio and cleanup as ending paths. If a
> request is marked REQ_NOWAIT and fails to get a request, the bio is
> cleaned up via rq_qos_cleanup() and ended in bio_wouldblock_error().
> This results in underflowing the inflight counter. Fix this by only
> accounting bios that were actually submitted.
> 
> Signed-off-by: Dennis Zhou <dennis@kernel.org>
> Cc: Josef Bacik <josef@toxicpanda.com>
> ---
>  block/blk-iolatency.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
> index 507212d75ee2..58bac44ba78a 100644
> --- a/block/blk-iolatency.c
> +++ b/block/blk-iolatency.c
> @@ -599,6 +599,10 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
>  	if (!blkg || !bio_flagged(bio, BIO_TRACKED))
>  		return;
>  
> +	/* We didn't actually submit this bio, don't account it. */
> +	if (bio->bi_status == BLK_STS_AGAIN)
> +		return;
> +
>  	iolat = blkg_to_lat(bio->bi_blkg);
>  	if (!iolat)
>  		return;
> -- 
> 2.17.1
> 

Can you please take a look at this?

Thanks,
Dennis
Jens Axboe June 20, 2019, 9:29 a.m. UTC | #2
On 5/23/19 2:10 PM, Dennis Zhou wrote:
> As is, iolatency recognizes done_bio and cleanup as ending paths. If a
> request is marked REQ_NOWAIT and fails to get a request, the bio is
> cleaned up via rq_qos_cleanup() and ended in bio_wouldblock_error().
> This results in underflowing the inflight counter. Fix this by only
> accounting bios that were actually submitted.

Looks good to me, applied.
diff mbox series

Patch

diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 507212d75ee2..58bac44ba78a 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -599,6 +599,10 @@  static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
 	if (!blkg || !bio_flagged(bio, BIO_TRACKED))
 		return;
 
+	/* We didn't actually submit this bio, don't account it. */
+	if (bio->bi_status == BLK_STS_AGAIN)
+		return;
+
 	iolat = blkg_to_lat(bio->bi_blkg);
 	if (!iolat)
 		return;