On Thu, 2 Feb 2023 12:25:59 -0500, "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote:
> On Thu, Feb 02, 2023 at 07:00:49PM +0800, Xuan Zhuo wrote:
> > Since xsk's TX queue is consumed by TX NAPI, if sq is bound to xsk, then
> > we must stop tx napi from being disabled.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> > ---
> > drivers/net/virtio/main.c | 9 ++++++++-
> > 1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
> > index ed79e750bc6c..232cf151abff 100644
> > --- a/drivers/net/virtio/main.c
> > +++ b/drivers/net/virtio/main.c
> > @@ -2728,8 +2728,15 @@ static int virtnet_set_coalesce(struct net_device *dev,
> > return ret;
> >
> > if (update_napi) {
> > - for (i = 0; i < vi->max_queue_pairs; i++)
> > + for (i = 0; i < vi->max_queue_pairs; i++) {
> > + /* xsk xmit depend on the tx napi. So if xsk is active,
>
> depends.
>
> > + * prevent modifications to tx napi.
> > + */
> > + if (rtnl_dereference(vi->sq[i].xsk.pool))
> > + continue;
> > +
> > vi->sq[i].napi.weight = napi_weight;
>
> I don't get it.
> changing napi weight does not work then.
> why is this ok?
static void skb_xmit_done(struct virtqueue *vq)
{
struct virtnet_info *vi = vq->vdev->priv;
struct napi_struct *napi = &vi->sq[vq2txq(vq)].napi;
/* Suppress further interrupts. */
virtqueue_disable_cb(vq);
if (napi->weight)
virtqueue_napi_schedule(napi, vq);
else
/* We were probably waiting for more output buffers. */
netif_wake_subqueue(vi->dev, vq2txq(vq));
}
If the weight is 0, tx napi will not be triggered again.
Thanks.
>
>
> > + }
> > }
> >
> > return ret;
> > --
> > 2.32.0.3.g01195cf9f
>
