| Message ID | 20220629065656.54420-40-xuanzhuo@linux.alibaba.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | virtio pci support VIRTIO_F_RING_RESET | expand |
在 2022/6/29 14:56, Xuan Zhuo 写道: > This patch implements the resize function of the tx queues. > Based on this function, it is possible to modify the ring num of the > queue. > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> > --- > drivers/net/virtio_net.c | 48 ++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 48 insertions(+) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 6ab16fd193e5..fd358462f802 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -135,6 +135,9 @@ struct send_queue { > struct virtnet_sq_stats stats; > > struct napi_struct napi; > + > + /* Record whether sq is in reset state. */ > + bool reset; > }; > > /* Internal representation of a receive virtqueue */ > @@ -279,6 +282,7 @@ struct padded_vnet_hdr { > }; > > static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf); > +static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf); > > static bool is_xdp_frame(void *ptr) > { > @@ -1603,6 +1607,11 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) > return; > > if (__netif_tx_trylock(txq)) { > + if (READ_ONCE(sq->reset)) { > + __netif_tx_unlock(txq); > + return; > + } > + > do { > virtqueue_disable_cb(sq->vq); > free_old_xmit_skbs(sq, true); > @@ -1868,6 +1877,45 @@ static int virtnet_rx_resize(struct virtnet_info *vi, > return err; > } > > +static int virtnet_tx_resize(struct virtnet_info *vi, > + struct send_queue *sq, u32 ring_num) > +{ > + struct netdev_queue *txq; > + int err, qindex; > + > + qindex = sq - vi->sq; > + > + virtnet_napi_tx_disable(&sq->napi); > + > + txq = netdev_get_tx_queue(vi->dev, qindex); > + > + /* 1. wait all ximt complete > + * 2. fix the race of netif_stop_subqueue() vs netif_start_subqueue() > + */ > + __netif_tx_lock_bh(txq); > + > + /* Prevent rx poll from accessing sq. */ > + WRITE_ONCE(sq->reset, true); Can we simply disable RX NAPI here? Thanks > + > + /* Prevent the upper layer from trying to send packets. */ > + netif_stop_subqueue(vi->dev, qindex); > + > + __netif_tx_unlock_bh(txq); > + > + err = virtqueue_resize(sq->vq, ring_num, virtnet_sq_free_unused_buf); > + if (err) > + netdev_err(vi->dev, "resize tx fail: tx queue index: %d err: %d\n", qindex, err); > + > + /* Memory barrier before set reset and start subqueue. */ > + smp_mb(); > + > + WRITE_ONCE(sq->reset, false); > + netif_tx_wake_queue(txq); > + > + virtnet_napi_tx_enable(vi, sq->vq, &sq->napi); > + return err; > +} > + > /* > * Send command via the control virtqueue and check status. Commands > * supported by the hypervisor, as indicated by feature bits, should
On Mon, 4 Jul 2022 11:45:52 +0800, Jason Wang <jasowang@redhat.com> wrote: > > 在 2022/6/29 14:56, Xuan Zhuo 写道: > > This patch implements the resize function of the tx queues. > > Based on this function, it is possible to modify the ring num of the > > queue. > > > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> > > --- > > drivers/net/virtio_net.c | 48 ++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 48 insertions(+) > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > index 6ab16fd193e5..fd358462f802 100644 > > --- a/drivers/net/virtio_net.c > > +++ b/drivers/net/virtio_net.c > > @@ -135,6 +135,9 @@ struct send_queue { > > struct virtnet_sq_stats stats; > > > > struct napi_struct napi; > > + > > + /* Record whether sq is in reset state. */ > > + bool reset; > > }; > > > > /* Internal representation of a receive virtqueue */ > > @@ -279,6 +282,7 @@ struct padded_vnet_hdr { > > }; > > > > static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf); > > +static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf); > > > > static bool is_xdp_frame(void *ptr) > > { > > @@ -1603,6 +1607,11 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) > > return; > > > > if (__netif_tx_trylock(txq)) { > > + if (READ_ONCE(sq->reset)) { > > + __netif_tx_unlock(txq); > > + return; > > + } > > + > > do { > > virtqueue_disable_cb(sq->vq); > > free_old_xmit_skbs(sq, true); > > @@ -1868,6 +1877,45 @@ static int virtnet_rx_resize(struct virtnet_info *vi, > > return err; > > } > > > > +static int virtnet_tx_resize(struct virtnet_info *vi, > > + struct send_queue *sq, u32 ring_num) > > +{ > > + struct netdev_queue *txq; > > + int err, qindex; > > + > > + qindex = sq - vi->sq; > > + > > + virtnet_napi_tx_disable(&sq->napi); > > + > > + txq = netdev_get_tx_queue(vi->dev, qindex); > > + > > + /* 1. wait all ximt complete > > + * 2. fix the race of netif_stop_subqueue() vs netif_start_subqueue() > > + */ > > + __netif_tx_lock_bh(txq); > > + > > + /* Prevent rx poll from accessing sq. */ > > + WRITE_ONCE(sq->reset, true); > > > Can we simply disable RX NAPI here? Disable rx napi is indeed a simple solution. But I hope that when dealing with tx, it will not affect rx. Thanks. > > Thanks > > > > + > > + /* Prevent the upper layer from trying to send packets. */ > > + netif_stop_subqueue(vi->dev, qindex); > > + > > + __netif_tx_unlock_bh(txq); > > + > > + err = virtqueue_resize(sq->vq, ring_num, virtnet_sq_free_unused_buf); > > + if (err) > > + netdev_err(vi->dev, "resize tx fail: tx queue index: %d err: %d\n", qindex, err); > > + > > + /* Memory barrier before set reset and start subqueue. */ > > + smp_mb(); > > + > > + WRITE_ONCE(sq->reset, false); > > + netif_tx_wake_queue(txq); > > + > > + virtnet_napi_tx_enable(vi, sq->vq, &sq->napi); > > + return err; > > +} > > + > > /* > > * Send command via the control virtqueue and check status. Commands > > * supported by the hypervisor, as indicated by feature bits, should >
On Tue, Jul 5, 2022 at 10:01 AM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote: > > On Mon, 4 Jul 2022 11:45:52 +0800, Jason Wang <jasowang@redhat.com> wrote: > > > > 在 2022/6/29 14:56, Xuan Zhuo 写道: > > > This patch implements the resize function of the tx queues. > > > Based on this function, it is possible to modify the ring num of the > > > queue. > > > > > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> > > > --- > > > drivers/net/virtio_net.c | 48 ++++++++++++++++++++++++++++++++++++++++ > > > 1 file changed, 48 insertions(+) > > > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > > index 6ab16fd193e5..fd358462f802 100644 > > > --- a/drivers/net/virtio_net.c > > > +++ b/drivers/net/virtio_net.c > > > @@ -135,6 +135,9 @@ struct send_queue { > > > struct virtnet_sq_stats stats; > > > > > > struct napi_struct napi; > > > + > > > + /* Record whether sq is in reset state. */ > > > + bool reset; > > > }; > > > > > > /* Internal representation of a receive virtqueue */ > > > @@ -279,6 +282,7 @@ struct padded_vnet_hdr { > > > }; > > > > > > static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf); > > > +static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf); > > > > > > static bool is_xdp_frame(void *ptr) > > > { > > > @@ -1603,6 +1607,11 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) > > > return; > > > > > > if (__netif_tx_trylock(txq)) { > > > + if (READ_ONCE(sq->reset)) { > > > + __netif_tx_unlock(txq); > > > + return; > > > + } > > > + > > > do { > > > virtqueue_disable_cb(sq->vq); > > > free_old_xmit_skbs(sq, true); > > > @@ -1868,6 +1877,45 @@ static int virtnet_rx_resize(struct virtnet_info *vi, > > > return err; > > > } > > > > > > +static int virtnet_tx_resize(struct virtnet_info *vi, > > > + struct send_queue *sq, u32 ring_num) > > > +{ > > > + struct netdev_queue *txq; > > > + int err, qindex; > > > + > > > + qindex = sq - vi->sq; > > > + > > > + virtnet_napi_tx_disable(&sq->napi); > > > + > > > + txq = netdev_get_tx_queue(vi->dev, qindex); > > > + > > > + /* 1. wait all ximt complete > > > + * 2. fix the race of netif_stop_subqueue() vs netif_start_subqueue() > > > + */ > > > + __netif_tx_lock_bh(txq); > > > + > > > + /* Prevent rx poll from accessing sq. */ > > > + WRITE_ONCE(sq->reset, true); > > > > > > Can we simply disable RX NAPI here? > > Disable rx napi is indeed a simple solution. But I hope that when dealing with > tx, it will not affect rx. Ok, but I think we've already synchronized with tx lock here, isn't it? Thanks > > Thanks. > > > > > > Thanks > > > > > > > + > > > + /* Prevent the upper layer from trying to send packets. */ > > > + netif_stop_subqueue(vi->dev, qindex); > > > + > > > + __netif_tx_unlock_bh(txq); > > > + > > > + err = virtqueue_resize(sq->vq, ring_num, virtnet_sq_free_unused_buf); > > > + if (err) > > > + netdev_err(vi->dev, "resize tx fail: tx queue index: %d err: %d\n", qindex, err); > > > + > > > + /* Memory barrier before set reset and start subqueue. */ > > > + smp_mb(); > > > + > > > + WRITE_ONCE(sq->reset, false); > > > + netif_tx_wake_queue(txq); > > > + > > > + virtnet_napi_tx_enable(vi, sq->vq, &sq->napi); > > > + return err; > > > +} > > > + > > > /* > > > * Send command via the control virtqueue and check status. Commands > > > * supported by the hypervisor, as indicated by feature bits, should > > >
On Fri, 8 Jul 2022 14:23:57 +0800, Jason Wang <jasowang@redhat.com> wrote: > On Tue, Jul 5, 2022 at 10:01 AM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote: > > > > On Mon, 4 Jul 2022 11:45:52 +0800, Jason Wang <jasowang@redhat.com> wrote: > > > > > > 在 2022/6/29 14:56, Xuan Zhuo 写道: > > > > This patch implements the resize function of the tx queues. > > > > Based on this function, it is possible to modify the ring num of the > > > > queue. > > > > > > > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> > > > > --- > > > > drivers/net/virtio_net.c | 48 ++++++++++++++++++++++++++++++++++++++++ > > > > 1 file changed, 48 insertions(+) > > > > > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > > > index 6ab16fd193e5..fd358462f802 100644 > > > > --- a/drivers/net/virtio_net.c > > > > +++ b/drivers/net/virtio_net.c > > > > @@ -135,6 +135,9 @@ struct send_queue { > > > > struct virtnet_sq_stats stats; > > > > > > > > struct napi_struct napi; > > > > + > > > > + /* Record whether sq is in reset state. */ > > > > + bool reset; > > > > }; > > > > > > > > /* Internal representation of a receive virtqueue */ > > > > @@ -279,6 +282,7 @@ struct padded_vnet_hdr { > > > > }; > > > > > > > > static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf); > > > > +static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf); > > > > > > > > static bool is_xdp_frame(void *ptr) > > > > { > > > > @@ -1603,6 +1607,11 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) > > > > return; > > > > > > > > if (__netif_tx_trylock(txq)) { > > > > + if (READ_ONCE(sq->reset)) { > > > > + __netif_tx_unlock(txq); > > > > + return; > > > > + } > > > > + > > > > do { > > > > virtqueue_disable_cb(sq->vq); > > > > free_old_xmit_skbs(sq, true); > > > > @@ -1868,6 +1877,45 @@ static int virtnet_rx_resize(struct virtnet_info *vi, > > > > return err; > > > > } > > > > > > > > +static int virtnet_tx_resize(struct virtnet_info *vi, > > > > + struct send_queue *sq, u32 ring_num) > > > > +{ > > > > + struct netdev_queue *txq; > > > > + int err, qindex; > > > > + > > > > + qindex = sq - vi->sq; > > > > + > > > > + virtnet_napi_tx_disable(&sq->napi); > > > > + > > > > + txq = netdev_get_tx_queue(vi->dev, qindex); > > > > + > > > > + /* 1. wait all ximt complete > > > > + * 2. fix the race of netif_stop_subqueue() vs netif_start_subqueue() > > > > + */ > > > > + __netif_tx_lock_bh(txq); > > > > + > > > > + /* Prevent rx poll from accessing sq. */ > > > > + WRITE_ONCE(sq->reset, true); > > > > > > > > > Can we simply disable RX NAPI here? > > > > Disable rx napi is indeed a simple solution. But I hope that when dealing with > > tx, it will not affect rx. > > Ok, but I think we've already synchronized with tx lock here, isn't it? Yes, do you have any questions about WRITE_ONCE()? There is a set false operation later, I did not use lock there, so I used WRITE/READ_ONCE uniformly. Thanks. > > Thanks > > > > > Thanks. > > > > > > > > > > Thanks > > > > > > > > > > + > > > > + /* Prevent the upper layer from trying to send packets. */ > > > > + netif_stop_subqueue(vi->dev, qindex); > > > > + > > > > + __netif_tx_unlock_bh(txq); > > > > + > > > > + err = virtqueue_resize(sq->vq, ring_num, virtnet_sq_free_unused_buf); > > > > + if (err) > > > > + netdev_err(vi->dev, "resize tx fail: tx queue index: %d err: %d\n", qindex, err); > > > > + > > > > + /* Memory barrier before set reset and start subqueue. */ > > > > + smp_mb(); > > > > + > > > > + WRITE_ONCE(sq->reset, false); > > > > + netif_tx_wake_queue(txq); > > > > + > > > > + virtnet_napi_tx_enable(vi, sq->vq, &sq->napi); > > > > + return err; > > > > +} > > > > + > > > > /* > > > > * Send command via the control virtqueue and check status. Commands > > > > * supported by the hypervisor, as indicated by feature bits, should > > > > > >
On Fri, Jul 15, 2022 at 4:32 PM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote: > > On Fri, 8 Jul 2022 14:23:57 +0800, Jason Wang <jasowang@redhat.com> wrote: > > On Tue, Jul 5, 2022 at 10:01 AM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote: > > > > > > On Mon, 4 Jul 2022 11:45:52 +0800, Jason Wang <jasowang@redhat.com> wrote: > > > > > > > > 在 2022/6/29 14:56, Xuan Zhuo 写道: > > > > > This patch implements the resize function of the tx queues. > > > > > Based on this function, it is possible to modify the ring num of the > > > > > queue. > > > > > > > > > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> > > > > > --- > > > > > drivers/net/virtio_net.c | 48 ++++++++++++++++++++++++++++++++++++++++ > > > > > 1 file changed, 48 insertions(+) > > > > > > > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > > > > index 6ab16fd193e5..fd358462f802 100644 > > > > > --- a/drivers/net/virtio_net.c > > > > > +++ b/drivers/net/virtio_net.c > > > > > @@ -135,6 +135,9 @@ struct send_queue { > > > > > struct virtnet_sq_stats stats; > > > > > > > > > > struct napi_struct napi; > > > > > + > > > > > + /* Record whether sq is in reset state. */ > > > > > + bool reset; > > > > > }; > > > > > > > > > > /* Internal representation of a receive virtqueue */ > > > > > @@ -279,6 +282,7 @@ struct padded_vnet_hdr { > > > > > }; > > > > > > > > > > static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf); > > > > > +static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf); > > > > > > > > > > static bool is_xdp_frame(void *ptr) > > > > > { > > > > > @@ -1603,6 +1607,11 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) > > > > > return; > > > > > > > > > > if (__netif_tx_trylock(txq)) { > > > > > + if (READ_ONCE(sq->reset)) { > > > > > + __netif_tx_unlock(txq); > > > > > + return; > > > > > + } > > > > > + > > > > > do { > > > > > virtqueue_disable_cb(sq->vq); > > > > > free_old_xmit_skbs(sq, true); > > > > > @@ -1868,6 +1877,45 @@ static int virtnet_rx_resize(struct virtnet_info *vi, > > > > > return err; > > > > > } > > > > > > > > > > +static int virtnet_tx_resize(struct virtnet_info *vi, > > > > > + struct send_queue *sq, u32 ring_num) > > > > > +{ > > > > > + struct netdev_queue *txq; > > > > > + int err, qindex; > > > > > + > > > > > + qindex = sq - vi->sq; > > > > > + > > > > > + virtnet_napi_tx_disable(&sq->napi); > > > > > + > > > > > + txq = netdev_get_tx_queue(vi->dev, qindex); > > > > > + > > > > > + /* 1. wait all ximt complete > > > > > + * 2. fix the race of netif_stop_subqueue() vs netif_start_subqueue() > > > > > + */ > > > > > + __netif_tx_lock_bh(txq); > > > > > + > > > > > + /* Prevent rx poll from accessing sq. */ > > > > > + WRITE_ONCE(sq->reset, true); > > > > > > > > > > > > Can we simply disable RX NAPI here? > > > > > > Disable rx napi is indeed a simple solution. But I hope that when dealing with > > > tx, it will not affect rx. > > > > Ok, but I think we've already synchronized with tx lock here, isn't it? > > Yes, do you have any questions about WRITE_ONCE()? There is a set false operation > later, I did not use lock there, so I used WRITE/READ_ONCE > uniformly. I mean, since we've already used tx locks somewhere, we'd better use them here as well at least as a start. Thanks > > Thanks. > > > > > Thanks > > > > > > > > Thanks. > > > > > > > > > > > > > > Thanks > > > > > > > > > > > > > + > > > > > + /* Prevent the upper layer from trying to send packets. */ > > > > > + netif_stop_subqueue(vi->dev, qindex); > > > > > + > > > > > + __netif_tx_unlock_bh(txq); > > > > > + > > > > > + err = virtqueue_resize(sq->vq, ring_num, virtnet_sq_free_unused_buf); > > > > > + if (err) > > > > > + netdev_err(vi->dev, "resize tx fail: tx queue index: %d err: %d\n", qindex, err); > > > > > + > > > > > + /* Memory barrier before set reset and start subqueue. */ > > > > > + smp_mb(); > > > > > + > > > > > + WRITE_ONCE(sq->reset, false); > > > > > + netif_tx_wake_queue(txq); > > > > > + > > > > > + virtnet_napi_tx_enable(vi, sq->vq, &sq->napi); > > > > > + return err; > > > > > +} > > > > > + > > > > > /* > > > > > * Send command via the control virtqueue and check status. Commands > > > > > * supported by the hypervisor, as indicated by feature bits, should > > > > > > > > > >
On Mon, 18 Jul 2022 16:57:53 +0800, Jason Wang <jasowang@redhat.com> wrote: > On Fri, Jul 15, 2022 at 4:32 PM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote: > > > > On Fri, 8 Jul 2022 14:23:57 +0800, Jason Wang <jasowang@redhat.com> wrote: > > > On Tue, Jul 5, 2022 at 10:01 AM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote: > > > > > > > > On Mon, 4 Jul 2022 11:45:52 +0800, Jason Wang <jasowang@redhat.com> wrote: > > > > > > > > > > 在 2022/6/29 14:56, Xuan Zhuo 写道: > > > > > > This patch implements the resize function of the tx queues. > > > > > > Based on this function, it is possible to modify the ring num of the > > > > > > queue. > > > > > > > > > > > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> > > > > > > --- > > > > > > drivers/net/virtio_net.c | 48 ++++++++++++++++++++++++++++++++++++++++ > > > > > > 1 file changed, 48 insertions(+) > > > > > > > > > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > > > > > index 6ab16fd193e5..fd358462f802 100644 > > > > > > --- a/drivers/net/virtio_net.c > > > > > > +++ b/drivers/net/virtio_net.c > > > > > > @@ -135,6 +135,9 @@ struct send_queue { > > > > > > struct virtnet_sq_stats stats; > > > > > > > > > > > > struct napi_struct napi; > > > > > > + > > > > > > + /* Record whether sq is in reset state. */ > > > > > > + bool reset; > > > > > > }; > > > > > > > > > > > > /* Internal representation of a receive virtqueue */ > > > > > > @@ -279,6 +282,7 @@ struct padded_vnet_hdr { > > > > > > }; > > > > > > > > > > > > static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf); > > > > > > +static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf); > > > > > > > > > > > > static bool is_xdp_frame(void *ptr) > > > > > > { > > > > > > @@ -1603,6 +1607,11 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) > > > > > > return; > > > > > > > > > > > > if (__netif_tx_trylock(txq)) { > > > > > > + if (READ_ONCE(sq->reset)) { > > > > > > + __netif_tx_unlock(txq); > > > > > > + return; > > > > > > + } > > > > > > + > > > > > > do { > > > > > > virtqueue_disable_cb(sq->vq); > > > > > > free_old_xmit_skbs(sq, true); > > > > > > @@ -1868,6 +1877,45 @@ static int virtnet_rx_resize(struct virtnet_info *vi, > > > > > > return err; > > > > > > } > > > > > > > > > > > > +static int virtnet_tx_resize(struct virtnet_info *vi, > > > > > > + struct send_queue *sq, u32 ring_num) > > > > > > +{ > > > > > > + struct netdev_queue *txq; > > > > > > + int err, qindex; > > > > > > + > > > > > > + qindex = sq - vi->sq; > > > > > > + > > > > > > + virtnet_napi_tx_disable(&sq->napi); > > > > > > + > > > > > > + txq = netdev_get_tx_queue(vi->dev, qindex); > > > > > > + > > > > > > + /* 1. wait all ximt complete > > > > > > + * 2. fix the race of netif_stop_subqueue() vs netif_start_subqueue() > > > > > > + */ > > > > > > + __netif_tx_lock_bh(txq); > > > > > > + > > > > > > + /* Prevent rx poll from accessing sq. */ > > > > > > + WRITE_ONCE(sq->reset, true); > > > > > > > > > > > > > > > Can we simply disable RX NAPI here? > > > > > > > > Disable rx napi is indeed a simple solution. But I hope that when dealing with > > > > tx, it will not affect rx. > > > > > > Ok, but I think we've already synchronized with tx lock here, isn't it? > > > > Yes, do you have any questions about WRITE_ONCE()? There is a set false operation > > later, I did not use lock there, so I used WRITE/READ_ONCE > > uniformly. > > I mean, since we've already used tx locks somewhere, we'd better use > them here as well at least as a start. OK. next version will fix. Thanks. +static int virtnet_tx_resize(struct virtnet_info *vi, + struct send_queue *sq, u32 ring_num) +{ + struct netdev_queue *txq; + int err, qindex; + + qindex = sq - vi->sq; + + virtnet_napi_tx_disable(&sq->napi); + + txq = netdev_get_tx_queue(vi->dev, qindex); + + /* 1. wait all ximt complete + * 2. fix the race of netif_stop_subqueue() vs netif_start_subqueue() + */ + __netif_tx_lock_bh(txq); + + sq->reset = true; + + /* Prevent the upper layer from trying to send packets. */ + netif_stop_subqueue(vi->dev, qindex); + + __netif_tx_unlock_bh(txq); + + err = virtqueue_resize(sq->vq, ring_num, virtnet_sq_free_unused_buf); + if (err) + netdev_err(vi->dev, "resize tx fail: tx queue index: %d err: %d\n", qindex, err); + + __netif_tx_lock_bh(txq); + sq->reset = false; + netif_tx_wake_queue(txq); + __netif_tx_unlock_bh(txq); + + virtnet_napi_tx_enable(vi, sq->vq, &sq->napi); + return err; +} > > Thanks > > > > > Thanks. > > > > > > > > Thanks > > > > > > > > > > > Thanks. > > > > > > > > > > > > > > > > > > Thanks > > > > > > > > > > > > > > > > + > > > > > > + /* Prevent the upper layer from trying to send packets. */ > > > > > > + netif_stop_subqueue(vi->dev, qindex); > > > > > > + > > > > > > + __netif_tx_unlock_bh(txq); > > > > > > + > > > > > > + err = virtqueue_resize(sq->vq, ring_num, virtnet_sq_free_unused_buf); > > > > > > + if (err) > > > > > > + netdev_err(vi->dev, "resize tx fail: tx queue index: %d err: %d\n", qindex, err); > > > > > > + > > > > > > + /* Memory barrier before set reset and start subqueue. */ > > > > > > + smp_mb(); > > > > > > + > > > > > > + WRITE_ONCE(sq->reset, false); > > > > > > + netif_tx_wake_queue(txq); > > > > > > + > > > > > > + virtnet_napi_tx_enable(vi, sq->vq, &sq->napi); > > > > > > + return err; > > > > > > +} > > > > > > + > > > > > > /* > > > > > > * Send command via the control virtqueue and check status. Commands > > > > > > * supported by the hypervisor, as indicated by feature bits, should > > > > > > > > > > > > > > >
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 6ab16fd193e5..fd358462f802 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -135,6 +135,9 @@ struct send_queue { struct virtnet_sq_stats stats; struct napi_struct napi; + + /* Record whether sq is in reset state. */ + bool reset; }; /* Internal representation of a receive virtqueue */ @@ -279,6 +282,7 @@ struct padded_vnet_hdr { }; static void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf); +static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf); static bool is_xdp_frame(void *ptr) { @@ -1603,6 +1607,11 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) return; if (__netif_tx_trylock(txq)) { + if (READ_ONCE(sq->reset)) { + __netif_tx_unlock(txq); + return; + } + do { virtqueue_disable_cb(sq->vq); free_old_xmit_skbs(sq, true); @@ -1868,6 +1877,45 @@ static int virtnet_rx_resize(struct virtnet_info *vi, return err; } +static int virtnet_tx_resize(struct virtnet_info *vi, + struct send_queue *sq, u32 ring_num) +{ + struct netdev_queue *txq; + int err, qindex; + + qindex = sq - vi->sq; + + virtnet_napi_tx_disable(&sq->napi); + + txq = netdev_get_tx_queue(vi->dev, qindex); + + /* 1. wait all ximt complete + * 2. fix the race of netif_stop_subqueue() vs netif_start_subqueue() + */ + __netif_tx_lock_bh(txq); + + /* Prevent rx poll from accessing sq. */ + WRITE_ONCE(sq->reset, true); + + /* Prevent the upper layer from trying to send packets. */ + netif_stop_subqueue(vi->dev, qindex); + + __netif_tx_unlock_bh(txq); + + err = virtqueue_resize(sq->vq, ring_num, virtnet_sq_free_unused_buf); + if (err) + netdev_err(vi->dev, "resize tx fail: tx queue index: %d err: %d\n", qindex, err); + + /* Memory barrier before set reset and start subqueue. */ + smp_mb(); + + WRITE_ONCE(sq->reset, false); + netif_tx_wake_queue(txq); + + virtnet_napi_tx_enable(vi, sq->vq, &sq->napi); + return err; +} + /* * Send command via the control virtqueue and check status. Commands * supported by the hypervisor, as indicated by feature bits, should
This patch implements the resize function of the tx queues. Based on this function, it is possible to modify the ring num of the queue. Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> --- drivers/net/virtio_net.c | 48 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+)