lguest: net block unneeded receive queue update notifications Number of exits transmitting 10GB Guest->Host before: network xmit 7858610 recv 118136 After: network xmit 7750233 recv 1 Signed-off-by: Rusty Russell --- Documentation/lguest/lguest.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff -r e86c4683fcf0 Documentation/lguest/lguest.c --- a/Documentation/lguest/lguest.c Mon Jul 28 11:02:01 2008 +1000 +++ b/Documentation/lguest/lguest.c Mon Jul 28 11:26:48 2008 +1000 @@ -933,6 +933,11 @@ static bool handle_tun_input(int fd, str /* FIXME: Actually want DRIVER_ACTIVE here. */ if (dev->desc->status & VIRTIO_CONFIG_S_DRIVER_OK) warn("network: no dma buffer!"); + + /* Now tell it we want to know if new things appear. */ + dev->vq->vring.used->flags &= ~VRING_USED_F_NO_NOTIFY; + wmb(); + /* We'll turn this back on if input buffers are registered. */ return false; } else if (out_num) @@ -967,6 +972,13 @@ static void enable_fd(int fd, struct vir add_device_fd(vq->dev->fd); /* Tell waker to listen to it again */ write(waker_fd, &vq->dev->fd, sizeof(vq->dev->fd)); +} + +static void net_enable_fd(int fd, struct virtqueue *vq) +{ + /* We don't need to know again when Guest refills receive buffer. */ + vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY; + enable_fd(fd, vq); } /* When the Guest tells us they updated the status field, we handle it. */ @@ -1426,7 +1438,7 @@ static void setup_tun_net(char *arg) /* Network devices need a receive and a send queue, just like * console. */ - add_virtqueue(dev, VIRTQUEUE_NUM, enable_fd); + add_virtqueue(dev, VIRTQUEUE_NUM, net_enable_fd); add_virtqueue(dev, VIRTQUEUE_NUM, handle_net_output); /* We need a socket to perform the magic network ioctls to bring up the