From mboxrd@z Thu Jan  1 00:00:00 1970
From: Kevin Traynor <ktraynor@redhat.com>
Subject: Re: [PATCH 1/5] net/virtio: fix vector Rx break caused
 by rxq flushing
Date: Fri, 8 Dec 2017 10:17:22 +0000
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References: <20171207053059.19487-1-tiwei.bie@intel.com>
 <20171207053059.19487-2-tiwei.bie@intel.com>
 <9407e2ce-8b2b-9a9d-a493-1757609184a9@redhat.com>
 <20171208023034.4f5u3fujmupraaia@debian-xvivbkq>
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Cc: yliu@fridaylinux.org, maxime.coquelin@redhat.com, dev@dpdk.org,
 antonio.fischetti@intel.com, stable@dpdk.org,
 "Kavanagh, Mark B" <mark.b.kavanagh@intel.com>
To: Tiwei Bie <tiwei.bie@intel.com>
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On 12/08/2017 02:30 AM, Tiwei Bie wrote:
> On Thu, Dec 07, 2017 at 04:00:57PM +0000, Kevin Traynor wrote:
>> On 12/07/2017 05:30 AM, Tiwei Bie wrote:
>>> The vector Rx will be broken if backend has consumed all
>>> the descs in the avail ring before the device is started.
>>> Because in current implementation, vector Rx will return
>>> immediately without refilling the avail ring if the used
>>> ring is empty. So we have to refill the avail ring after
>>> flushing the elements in the used ring for vector Rx.
>>>
>>> Besides, vector Rx has a different ring layout assumption
>>> and mbuf management. So we need to handle it differently.
>>>
>>
>> Hi Tiwei, does the issue only occur with the vector rx? How about if the
>> simple rx is used because VIRTIO_NET_F_MRG_RXBUF is set?
> 
> Hi Kevin,
> 
> Yes, you are right! The issue only occurs with the vector
> Rx. The vector Rx (i.e. the simple Rx) won't be used if
> VIRTIO_NET_F_MRG_RXBUF is set.
> 
> Best regards,
> Tiwei Bie
> 

Thanks for clarifying this Tiwei,

Kevin.