Re: [net-next RFC V5 5/5] virtio_net: support negotiating the number of queues through ctrl vq

From: Jason Wang <jasowang@redhat.com>
To: Amos Kong <akong@redhat.com>
Cc: Sasha Levin <levinsasha928@gmail.com>,
	mst@redhat.com, mashirle@us.ibm.com, krkumar2@in.ibm.com,
	habanero@linux.vnet.ibm.com, rusty@rustcorp.com.au,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org, edumazet@google.com,
	tahm@linux.vnet.ibm.com, jwhan@filewood.snu.ac.kr,
	davem@davemloft.net, kvm@vger.kernel.org, sri@us.ibm.com
Subject: Re: [net-next RFC V5 5/5] virtio_net: support negotiating the number of queues through ctrl vq
Date: Fri, 06 Jul 2012 15:46:50 +0800	[thread overview]
Message-ID: <4FF697EA.807@redhat.com> (raw)
In-Reply-To: <4FF5F3F7.8090307@redhat.com>

On 07/06/2012 04:07 AM, Amos Kong wrote:
> On 07/05/2012 08:51 PM, Sasha Levin wrote:
>> On Thu, 2012-07-05 at 18:29 +0800, Jason Wang wrote:
>>> @@ -1387,6 +1404,10 @@ static int virtnet_probe(struct virtio_device *vdev)
>>>          if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
>>>                  vi->has_cvq = true;
>>>
>
>>> +       /* Use single tx/rx queue pair as default */
>>> +       vi->num_queue_pairs = 1;
>>> +       vi->total_queue_pairs = num_queue_pairs;
> vi->total_queue_pairs also should be set to 1
>
>             vi->total_queue_pairs = 1;

Hi Amos:

total_queue_pairs is the max number of queue pairs that the deivce could 
provide, so it's ok here.
>> The code is using this "default" even if the amount of queue pairs it
>> wants was specified during initialization. This basically limits any
>> device to use 1 pair when starting up.
>>
>> --
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>