Re: [PATCH net-next v4 2/2] virtio-net: add cond_resched() to the command waiting loop
From: Shannon Nelson <hidden>
Date: 2023-07-20 20:26:30
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On 7/20/23 1:38 AM, Jason Wang wrote:
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@redhat.com>
This still leaves hung processes, but at least it doesn't pin the CPU any more. Thanks. Reviewed-by: Shannon Nelson <redacted>
quoted hunk ↗ jump to hunk
--- 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 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization