From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Durrant Subject: Re: RING_HAS_UNCONSUMED_REQUESTS oddness Date: Thu, 13 Mar 2014 12:29:54 +0000 Message-ID: <9AAE0902D5BC7E449B7C8E4E778ABCD0285C81@AMSPEX01CL01.citrite.net> References: <5318987C.3030303@citrix.com> <1394552666.30915.64.camel@kazak.uk.xensource.com> <531F9B17.5060107@citrix.com> <1394620083.21145.21.camel@kazak.uk.xensource.com> <9AAE0902D5BC7E449B7C8E4E778ABCD0282CBF@AMSPEX01CL01.citrite.net> <53207226.7090002@citrix.com> <9AAE0902D5BC7E449B7C8E4E778ABCD02833BD@AMSPEX01CL01.citrite.net> <20140312154249.GP19620@zion.uk.xensource.com> <532087BB.6000100@citrix.com> <9AAE0902D5BC7E449B7C8E4E778ABCD0283744@AMSPEX01CL01.citrite.net> <5320B029.8040604@citrix.com> <9AAE0902D5BC7E449B7C8E4E778ABCD028577E@AMSPEX01CL01.citrite.net> <1394704978.25873.9.camel@kazak.uk.xensource.com> <9AAE0902D5BC7E449B7C8E4E778ABCD0285A59@AMSPEX01CL01.citrite.net> <1394713162.25873.48.camel@kazak.uk.xensource.com> <5321A46F.1070008@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta4.messagelabs.com ([85.158.143.247]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1WO4lo-00037D-El for xen-devel@lists.xenproject.org; Thu, 13 Mar 2014 12:29:56 +0000 In-Reply-To: <5321A46F.1070008@citrix.com> Content-Language: en-US List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Zoltan Kiss , Ian Campbell Cc: "xen-devel@lists.xenproject.org" , Wei Liu , "Tim (Xen.org)" List-Id: xen-devel@lists.xenproject.org > -----Original Message----- > From: Zoltan Kiss > Sent: 13 March 2014 12:29 > To: Ian Campbell; Paul Durrant > Cc: Wei Liu; xen-devel@lists.xenproject.org; Tim (Xen.org) > Subject: Re: [Xen-devel] RING_HAS_UNCONSUMED_REQUESTS oddness > > On 13/03/14 12:19, Ian Campbell wrote: > > On Thu, 2014-03-13 at 10:58 +0000, Paul Durrant wrote: > >>> -----Original Message----- > >>> From: Ian Campbell > >>> Sent: 13 March 2014 10:03 > >>> To: Paul Durrant > >>> Cc: Zoltan Kiss; Wei Liu; xen-devel@lists.xenproject.org; Tim (Xen.org) > >>> Subject: Re: [Xen-devel] RING_HAS_UNCONSUMED_REQUESTS > oddness > >>> > >>> On Thu, 2014-03-13 at 09:26 +0000, Paul Durrant wrote: > >>>> guarantee that netback will always respond in order on the rx ring. > >>> > >>> I don't believe this is guaranteed byt the protocol, even if it happens > >>> to work out that way for the Linux netback implementation. > >>> > >> > >> Indeed it's not guaranteed by the protocol but it's the only way that > >> (non-prefix) GSO can possibly work, which is why I think something > >> really needs to be documented. > > > > There are possibly ordering constraints on the completion of the gso > > info slot and the rest but I don't think there are any such restrictions > > on the fragment slots themselves, are there? > > Well, the Linux frontend doesn't take the id from the response, it just > assume that the response is in the same slot as the request. ... so for compatibilities sake, the ring had better complete in order! Paul