Michael S. Tsirkin
2023-Feb-02 17:25 UTC
[PATCH 24/33] virtio_net: xsk: stop disable tx napi
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 at linux.alibaba.com> > --- > 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?> + } > } > > return ret; > -- > 2.32.0.3.g01195cf9f
On Thu, 2 Feb 2023 12:25:59 -0500, "Michael S. Tsirkin" <mst at redhat.com> 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 at linux.alibaba.com> > > --- > > 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 >