From: Longjun Tang <[email protected]>
When busy-poll is active, napi_schedule_prep() returns false in
virtqueue_napi_schedule(), so virtqueue_disable_cb() is skipped.
The device may keep firing irqs until reaches virtqueue_napi_complete().
Under load (received == budget), it will lead to a large number
of spurious interrupts.
Fix it by disabling the callback at the virtnet_poll() entry.
This keeps the callback off while we poll and it is re-enabled by
virtqueue_napi_complete() when going idle.
Fixes: ceef438d613f ("virtio_net: remove custom busy_poll")
Acked-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Longjun Tang <[email protected]>
---
V1 -> V2: Remain agnostic to busy polling
V2 -> V3: Add fixes tag
V3 -> V4: Update commit message and remove some comments
---
drivers/net/virtio_net.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index f4adcfee7a80..569e4db187d1 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3008,6 +3008,8 @@ static int virtnet_poll(struct napi_struct *napi, int
budget)
unsigned int xdp_xmit = 0;
bool napi_complete;
+ virtqueue_disable_cb(rq->vq);
+
virtnet_poll_cleantx(rq, budget);
received = virtnet_receive(rq, budget, &xdp_xmit);
--
2.43.0
