Re: [PATCH net-next v7 3/4] net: vhost: factor out busy polling logic to vhost_net_busy_poll()

From: Jason Wang <jasowang@redhat.com>
To: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Cc: mst@redhat.com, makita.toshiaki@lab.ntt.co.jp,
	virtualization@lists.linux-foundation.org,
	Linux Kernel Network Developers <netdev@vger.kernel.org>
Subject: Re: [PATCH net-next v7 3/4] net: vhost: factor out busy polling logic to vhost_net_busy_poll()
Date: Thu, 2 Aug 2018 16:18:39 +0800	[thread overview]
Message-ID: <b4ffd376-6fa8-4d0c-5c3a-82d1b6e924d6@redhat.com> (raw)
In-Reply-To: <CAMDZJNWX7L4P0yO+-PeDFu_tmtLSntihO7rcLPB2GK4eN9zbwQ@mail.gmail.com>

On 2018年08月01日 17:52, Tonghao Zhang wrote:
>>> +
>>> +             cpu_relax();
>>> +     }
>>> +
>>> +     preempt_enable();
>>> +
>>> +     if (!rx)
>>> +             vhost_net_enable_vq(net, vq);
>> No need to enable rx virtqueue, if we are sure handle_rx() will be
>> called soon.
> If we disable rx virtqueue in handle_tx and don't send packets from
> guest anymore(handle_tx is not called), so we can wake up for sock rx.
> so the network is broken.

Not sure I understand here. I mean is we schedule work for handle_rx(), 
there's no need to enable it since handle_rx() will do this for us.

Thanks