From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next 0/2] xen-netback: Changes around carrier handling Date: Thu, 07 Aug 2014 22:29:05 -0700 (PDT) Message-ID: <20140807.222905.354652678816300998.davem@davemloft.net> References: <1407165658-20146-1-git-send-email-zoltan.kiss@citrix.com> <20140805.160748.1185917042908283028.davem@davemloft.net> <53E3AE21.50109@citrix.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: wei.liu2@citrix.com, Ian.Campbell@citrix.com, david.vrabel@citrix.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org To: zoltan.kiss@citrix.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:55651 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755799AbaHHF3G (ORCPT ); Fri, 8 Aug 2014 01:29:06 -0400 In-Reply-To: <53E3AE21.50109@citrix.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Zoltan Kiss Date: Thu, 7 Aug 2014 17:49:37 +0100 > David Vrabel pointed out an important question in a reply to the > previous version of this series: this patch deschedule NAPI if the > carrier goes down. The backend doesn't receive packets from the > guest. DavidVr and others said we shouldn't do this, the guest should > be able to transmit even if it's not able/willing to receive. Other > drivers doesn't deschedule NAPI at carrier off as well, however the > "carrier off" information comes from the hardware, not from an > untrusted guest who is not posting buffers on the receive ring. > I don't have any good argument why I did it the current way, other > than a hunch that it feels more natural. > David, do you have an opinion on that? Unless you have a strong reason for doing so, I don't think disabling receives when the TX path backs up is necessary.