From: Luis Chamberlain <mcgrof@kernel.org>
To: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Paul E. McKenney" <paulmck@kernel.org>,
shinichiro.kawasaki@wdc.com, Klaus Jensen <its@irrelevant.dk>,
linux-block@vger.kernel.org, Pankaj Raghav <pankydev8@gmail.com>,
Pankaj Raghav <p.raghav@samsung.com>,
Adam Manzanares <a.manzanares@samsung.com>
Subject: Re: blktests with zbd/006 ZNS triggers a possible false positive RCU stall
Date: Fri, 15 Apr 2022 10:35:33 -0700 [thread overview]
Message-ID: <Ylms5eFt2w8Cp1NI@bombadil.infradead.org> (raw)
In-Reply-To: <20220415043021.awhfncjjt22vyajg@offworld>
On Thu, Apr 14, 2022 at 09:30:21PM -0700, Davidlohr Bueso wrote:
> On Thu, 14 Apr 2022, Paul E. McKenney wrote:
>
> > On Thu, Apr 14, 2022 at 06:09:45PM -0700, Davidlohr Bueso wrote:
> > > No idea, however, why this would happen when using qemu as opposed to
> > > nbd.
> >
> > This one is a bit strange, no two ways about it.
> >
> > In theory, vCPU preemption is a possibility. In practice, if the
> > RCU grace-period kthread's vCPU was preempted for so long, I would
> > have expected the RCU CPU stall warning to complain about starvation.
> > But it still might be worth tracing context switches on the underlying
> > hypervisor.
>
> Right, but both cases are VMs which is what throws me off, regardless
> of the zns drive. Or is this not the case, Luis?
The nvme controller timeout and rcu splat happens on an 8 core KVM
guest. The hypervisor has no issues reported.
Does that answer the question?
Luis
next prev parent reply other threads:[~2022-04-15 17:35 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-14 22:02 blktests with zbd/006 ZNS triggers a possible false positive RCU stall Luis Chamberlain
2022-04-15 1:09 ` Davidlohr Bueso
2022-04-15 3:54 ` Paul E. McKenney
2022-04-15 4:30 ` Davidlohr Bueso
2022-04-15 17:35 ` Luis Chamberlain [this message]
2022-04-15 17:33 ` Luis Chamberlain
2022-04-15 17:42 ` Paul E. McKenney
2022-04-20 5:54 ` Shinichiro Kawasaki
2022-04-21 18:00 ` Luis Chamberlain
2022-04-27 5:08 ` Shinichiro Kawasaki
2022-04-27 5:42 ` Luis Chamberlain
2022-04-27 7:41 ` Klaus Jensen
2022-04-27 8:39 ` Damien Le Moal
2022-04-27 8:55 ` Klaus Jensen
2022-04-27 8:53 ` Shinichiro Kawasaki
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Ylms5eFt2w8Cp1NI@bombadil.infradead.org \
--to=mcgrof@kernel.org \
--cc=a.manzanares@samsung.com \
--cc=dave@stgolabs.net \
--cc=its@irrelevant.dk \
--cc=linux-block@vger.kernel.org \
--cc=p.raghav@samsung.com \
--cc=pankydev8@gmail.com \
--cc=paulmck@kernel.org \
--cc=shinichiro.kawasaki@wdc.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox