Re: [PATCH AUTOSEL 5.2 129/249] blk-iolatency: only account submitted bios

[Sasha Levin]

On Mon, Jul 15, 2019 at 03:58:06PM -0400, Dennis Zhou wrote:
> On Mon, Jul 15, 2019 at 09:44:54AM -0400, Sasha Levin wrote:
> > From: Dennis Zhou <dennis@xxxxxxxxxx>
> >
> > [ Upstream commit a3fb01ba5af066521f3f3421839e501bb2c71805 ]
> >
> > 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@xxxxxxxxxx>
> > Cc: Josef Bacik <josef@xxxxxxxxxxxxxx>
> > Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> > ---
> >  block/blk-iolatency.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
> > index d22e61bced86..c91b84bb9d0a 100644
> > --- a/block/blk-iolatency.c
> > +++ b/block/blk-iolatency.c
> > @@ -600,6 +600,10 @@ 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;
> > --
> > 2.20.1
>
> Hi Sasha,
>
> If you're going to pick this up, c9b3007feca0 ("blk-iolatency: fix
> STS_AGAIN handling") fixes this patch, so please pick that up too.

I've picked it up, thanks!

--
Thanks,
Sasha