[RFC,V7,2/7] virtio_ring: try to disable event index callbacks in virtqueue_disable_cb()
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Message ID 1432531444-50193-3-git-send-email-jasowang@redhat.com
State New, archived
Headers show
Series
  • enable tx interrupts for virtio-net
Related show

Commit Message

Jason Wang May 25, 2015, 5:23 a.m. UTC
Currently, we do nothing to prevent the callbacks in virtqueue_disable_cb() when
event index is used. This may cause spurious interrupts which may damage the
performance. This patch tries to publish last_used_idx as the used even to prevent
the callbacks.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/virtio/virtio_ring.c | 1 +
 1 file changed, 1 insertion(+)

Patch
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diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 096b857..a83aebc 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -538,6 +538,7 @@  void virtqueue_disable_cb(struct virtqueue *_vq)
 	struct vring_virtqueue *vq = to_vvq(_vq);
 
 	vq->vring.avail->flags |= cpu_to_virtio16(_vq->vdev, VRING_AVAIL_F_NO_INTERRUPT);
+	vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev, vq->last_used_idx);
 }
 EXPORT_SYMBOL_GPL(virtqueue_disable_cb);