From: Paolo Abeni <pabeni@redhat.com>
To: Jason Wang <jasowang@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>
Cc: netdev <netdev@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
virtualization <virtualization@lists.linux-foundation.org>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>,
Gautam Dawar <gautam.dawar@xilinx.com>,
davem <davem@davemloft.net>
Subject: Re: [PATCH net] virtio-net: add cond_resched() to the command waiting loop
Date: Tue, 06 Sep 2022 12:55:54 +0200 [thread overview]
Message-ID: <056ba905a2579903a372258383afdf6579767ad0.camel@redhat.com> (raw)
In-Reply-To: <CACGkMEtjQ0Jfok-gcRW+kuinsua2X0TscyTNfBJoXHny0Yob+g@mail.gmail.com>
On Mon, 2022-09-05 at 15:49 +0800, Jason Wang wrote:
> On Mon, Sep 5, 2022 at 3:15 PM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Mon, Sep 05, 2022 at 12:53:41PM +0800, Jason Wang wrote:
> > > Adding cond_resched() to the command waiting loop for a better
> > > co-operation with the scheduler. This allows to give CPU a breath to
> > > run other task(workqueue) instead of busy looping when preemption is
> > > not allowed.
> > >
> > > What's more important. This is a must for some vDPA parent to work
> > > since control virtqueue is emulated via a workqueue for those parents.
> > >
> > > Fixes: bda324fd037a ("vdpasim: control virtqueue support")
> >
> > That's a weird commit to fix. so it fixes the simulator?
>
> Yes, since the simulator is using a workqueue to handle control virtueue.
Uhmm... touching a driver for a simulator's sake looks a little weird.
Additionally, if the bug is vdpasim, I think it's better to try to
solve it there, if possible.
Looking at vdpasim_net_work() and vdpasim_blk_work() it looks like
neither needs a process context, so perhaps you could rework it to run
the work_fn() directly from vdpasim_kick_vq(), at least for the control
virtqueue?
Thanks!
Paolo
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next prev parent reply other threads:[~2022-09-06 10:56 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-05 4:53 [PATCH net] virtio-net: add cond_resched() to the command waiting loop Jason Wang
2022-09-05 7:15 ` Michael S. Tsirkin
2022-09-05 7:49 ` Jason Wang
2022-09-06 10:55 ` Paolo Abeni [this message]
2022-09-07 2:09 ` Jason Wang
2022-09-07 7:07 ` Paolo Abeni
2022-09-07 7:46 ` Michael S. Tsirkin
2022-09-08 2:21 ` Jason Wang
2022-09-08 5:19 ` Michael S. Tsirkin
2022-10-09 5:58 ` Jason Wang
2022-10-10 17:11 ` Michael S. Tsirkin
2022-10-12 3:19 ` Jason Wang
2022-10-17 7:15 ` Jason Wang
2022-10-17 20:09 ` Michael S. Tsirkin
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