At 2026-06-24 15:08:24, "Michael S. Tsirkin" <[email protected]> wrote: >On Wed, Jun 24, 2026 at 03:02:06PM +0800, Longjun Tang wrote: >> 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 re-enable > >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 >> --- >> drivers/net/virtio_net.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >> index f4adcfee7a80..0a11f2b32500 100644 >> --- a/drivers/net/virtio_net.c >> +++ b/drivers/net/virtio_net.c >> @@ -3008,6 +3008,11 @@ static int virtnet_poll(struct napi_struct *napi, int >> budget) >> unsigned int xdp_xmit = 0; >> bool napi_complete; >> >> + /* Keep callbacks suppressed for the duration of this poll, >> + * busy-poll need. > >I don't know what "busy-poll need" means. Just drop this part? >In fact, the whole comment can go, we know virtqueue_disable_cb >disables callbacks.
Thanks for your reply. I got it, see you next version. > >> + */ >> + virtqueue_disable_cb(rq->vq); >> + >> virtnet_poll_cleantx(rq, budget); >> >> received = virtnet_receive(rq, budget, &xdp_xmit); >> -- >> 2.43.0
