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Subject[RFC V7 PATCH 2/7] virtio_ring: try to disable event index callbacks in virtqueue_disable_cb()
Date
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(+)

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);

--
1.8.3.1


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