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Message-Id: <20230720083839.481487-3-jasowang@redhat.com>
Date: Thu, 20 Jul 2023 04:38:39 -0400
From: Jason Wang <jasowang@...hat.com>
To: mst@...hat.com, jasowang@...hat.com, xuanzhuo@...ux.alibaba.com
Cc: davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
pabeni@...hat.com, virtualization@...ts.linux-foundation.org,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
alvaro.karsz@...id-run.com, maxime.coquelin@...hat.com
Subject: [PATCH net-next v4 2/2] virtio-net: add cond_resched() to the command waiting loop
Adding cond_resched() to the command waiting loop for a better
co-operation with the scheduler. This allows to give CPU a breath to
run other task(workqueue) instead of busy looping when preemption is
not allowed on a device whose CVQ might be slow.
Signed-off-by: Jason Wang <jasowang@...hat.com>
---
drivers/net/virtio_net.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 9f3b1d6ac33d..e7533f29b219 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2314,8 +2314,10 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
* into the hypervisor, so the request should be handled immediately.
*/
while (!virtqueue_get_buf(vi->cvq, &tmp) &&
- !virtqueue_is_broken(vi->cvq))
+ !virtqueue_is_broken(vi->cvq)) {
+ cond_resched();
cpu_relax();
+ }
return vi->ctrl->status == VIRTIO_NET_OK;
}
--
2.39.3
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