netdev - Re: [PATCH] tun: use netif_receive_skb instead of netif_rx

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Message-ID: <52FB250A.9060702@redhat.com>
Date:	Wed, 12 Feb 2014 15:38:50 +0800
From:	Jason Wang <jasowang@...hat.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
CC:	Qin Chuanyu <qinchuanyu@...wei.com>, davem@...emloft.net,
	"Michael S. Tsirkin" <mst@...hat.com>,
	Anthony Liguori <anthony@...emonkey.ws>,
	KVM list <kvm@...r.kernel.org>, netdev@...r.kernel.org
Subject: Re: [PATCH] tun: use netif_receive_skb instead of netif_rx_ni

On 02/12/2014 02:26 PM, Eric Dumazet wrote:
> On Wed, 2014-02-12 at 13:50 +0800, Jason Wang wrote:
>> On 02/12/2014 01:47 PM, Eric Dumazet wrote:
>>> On Wed, 2014-02-12 at 13:28 +0800, Jason Wang wrote:
>>>
>>>> A question: without NAPI weight, could this starve other net devices?
>>> Not really, as net devices are serviced by softirq handler.
>>>
>>>
>> Yes, then the issue is tun could be starved by other net devices.
> How this patch changes anything to this 'problem' ?
>
> netif_rx_ni() can only be called if your process is not preempted by
> other high prio tasks/softirqs.
>
> If this process is scheduled on a cpu, then disabling bh to process
> _one_ packet wont fundamentally change dynamic of the system.
>

After looking at the code for a while, I agree it won't be a great change.

Thanks
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