On Tue, 30 Jul 2024 18:20:20 -0700, Jakub Kicinski <kuba@xxxxxxxxxx> wrote:
> On Mon, 29 Jul 2024 20:47:55 +0800 Heng Qi wrote:
> > Subject: [PATCH net] virtio_net: Avoid sending unnecessary vq coalescing commands
>
> subject currently reads like this is an optimization, could you
> rephrase?
Jason's rephrase will be used.
>
> > From the virtio spec:
> >
> > The driver MUST have negotiated the VIRTIO_NET_F_VQ_NOTF_COAL
> > feature when issuing commands VIRTIO_NET_CTRL_NOTF_COAL_VQ_SET
> > and VIRTIO_NET_CTRL_NOTF_COAL_VQ_GET.
> >
> > The driver must not send vq notification coalescing commands if
> > VIRTIO_NET_F_VQ_NOTF_COAL is not negotiated. This limitation of course
> > applies to vq resize.
> >
> > Fixes: f61fe5f081cf ("virtio-net: fix the vq coalescing setting for vq resize")
> > Signed-off-by: Heng Qi <hengqi@xxxxxxxxxxxxxxxxx>
> > ---
> > drivers/net/virtio_net.c | 29 +++++++++++++++++------------
> > 1 file changed, 17 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index 0383a3e136d6..eb115e807882 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -3708,6 +3708,7 @@ static int virtnet_set_ringparam(struct net_device *dev,
> > u32 rx_pending, tx_pending;
> > struct receive_queue *rq;
> > struct send_queue *sq;
> > + u32 pkts, usecs;
> > int i, err;
> >
> > if (ring->rx_mini_pending || ring->rx_jumbo_pending)
> > @@ -3740,11 +3741,13 @@ static int virtnet_set_ringparam(struct net_device *dev,
> > * through the VIRTIO_NET_CTRL_NOTF_COAL_TX_SET command, or, if the driver
> > * did not set any TX coalescing parameters, to 0.
> > */
> > - err = virtnet_send_tx_ctrl_coal_vq_cmd(vi, i,
> > - vi->intr_coal_tx.max_usecs,
> > - vi->intr_coal_tx.max_packets);
> > - if (err)
> > - return err;
> > + if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL)) {
> > + usecs = vi->intr_coal_tx.max_usecs;
> > + pkts = vi->intr_coal_tx.max_packets;
> > + err = virtnet_send_tx_ctrl_coal_vq_cmd(vi, i, usecs, pkts);
> > + if (err)
> > + return err;
>
> Can you check the feature inside the
> virtnet_send_.x_ctrl_coal_vq_cmd() helpers?
> 5 levels of indentation is a bit much
Makes sense. Will update in the next version.
Thanks.
> --
> pw-bot: cr
