From 4d6308aac3258ecad8444811a16951a919adc131 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sat, 4 Feb 2017 07:49:21 -0800 Subject: [PATCH] virtio_net: exploit napi_complete_done() return value Since commit 364b6055738b ("net: busy-poll: return busypolling status to drivers"), napi_complete_done() returns a boolean that can be used by drivers to conditionally rearm interrupts. This patch changes virtio_net to use this boolean to avoid a bit of overhead for busy-poll users. Jason reports about 1.1% improvement for 1 byte TCP_RR (burst 100). Signed-off-by: Eric Dumazet Acked-by: Jason Wang Cc: Michael S. Tsirkin Cc: Willem de Bruijn Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 0382827829d9..29982c7f6080 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1012,11 +1012,12 @@ static int virtnet_poll(struct napi_struct *napi, int budget) /* Out of packets? */ if (received < budget) { r = virtqueue_enable_cb_prepare(rq->vq); - napi_complete_done(napi, received); - if (unlikely(virtqueue_poll(rq->vq, r)) && - napi_schedule_prep(napi)) { - virtqueue_disable_cb(rq->vq); - __napi_schedule(napi); + if (napi_complete_done(napi, received)) { + if (unlikely(virtqueue_poll(rq->vq, r)) && + napi_schedule_prep(napi)) { + virtqueue_disable_cb(rq->vq); + __napi_schedule(napi); + } } } -- 2.20.1