From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tracy R Reed Subject: Xen/AoE skb frag array incompatibility Date: Thu, 07 Dec 2006 18:00:18 -0800 Message-ID: <4578C732.1020206@ultraviolet.org> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------000909030606040508020707" Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org This is a multi-part message in MIME format. --------------000909030606040508020707 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Greetings, Xen developers! I have been using AoE with Xen to great effect and I am very pleased with how the whole system has worked out. The two technologies really complement each other. I consider it the ultimate setup. Aside from the network switch (eventually to be remedied) my serving infrastructure has zero single points of failure. However, this virtualization paradise has a flaw: There seems to be some sort of incompatibility in the way AoE uses the skb frag array in the latest version of AoE (6-40) and in the way Xen uses it. This causes new AoE block devices to fail to be accessible among potentially other problems. Is anyone aware of this problem? It is not clear to me if it is a problem with Xen or if the fault lies in AoE. I have looked into it a bit but my kernel hacking talents are rather meager. Attached is a recent email from the AoE list discussing it. If you have any suggestions for the AoE folks they can be reached over at aoetools-discuss@lists.sourceforge.net -- Tracy R Reed http://ultraviolet.org A: Because we read from top to bottom, left to right Q: Why should I start my reply below the quoted text --------------000909030606040508020707 Content-Type: message/rfc822; name*0="Re: [Aoetools-discuss] Unable to open dev /dev/etherd/e1.6:" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename*0="Re: [Aoetools-discuss] Unable to open dev /dev/etherd/e1.6:" Return-Path: X-Original-To: treed@ultraviolet.org Delivered-To: treed@ultraviolet.org X-Greylist: domain auto-whitelisted by SQLgrey-1.6.7 Received: from coraid.com (ns1.coraid.com [65.14.39.133]) by mail.copilotconsulting.com (Postfix) with ESMTP id 5A230300F0 for ; Thu, 7 Dec 2006 07:31:46 -0800 (PST) Message-ID: <6bc653c54757da64842c5d286b15bee8@coraid.com> To: treed@ultraviolet.org, ecashin@coraid.com Cc: aoetools-discuss@lists.sourceforge.net Subject: Re: [Aoetools-discuss] Unable to open dev /dev/etherd/e1.6: From: Sam Hopkins Date: Thu, 7 Dec 2006 10:29:25 -0500 In-Reply-To: <4577E48C.7000907@ultraviolet.org> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-copilot-MailScanner-Information: Please contact the ISP for more information X-copilot-MailScanner: Found to be clean X-copilot-MailScanner-From: sah@coraid.com > Ed L. Cashin wrote: >> That sounds similar to the problem that Sam and Adi Kriegisch were >> recently discussing. It looked like an incompatibility between our >> use of "zero-copy writes" and the network layer in his Xen kernels. >> >> Adi Kriegisch said that version aoe6-23 worked for him. > > Hmm...I tried to compile the aoe6-23 version and ran into the old error: > > /root/aoe6-23/linux/drivers/block/aoe/aoenet.c:142: error: too many > arguments to function `skb_linearize' > > which I can easily fix...then I am reminded that with the aoe driver in > the stock 2.6.16 kernel I would get the error "Can't schedule work for > e1.1, it's already on! (This really shouldn't happen)" but it seems that > is the very old version 14. Hopefully if I just fix the skb_linearize > arguments in aoe6-23 it will work acceptably. I just hate being the only > one running a unique version of the driver. It would be great if someone close to the Xen community would engage them about our use of the skb frag array to figure out why this is happening, since it's a problem that seems to be unique to that environment. It is a detriment to aoe that one must hack on old drivers with missing features to overcome a bug that's already been identified. We're not going to maintain an aoe6-23 driver for Xen folks to workaround a bug. Fix the bug! Cheers, Sam --------------000909030606040508020707 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel --------------000909030606040508020707--