From mboxrd@z Thu Jan 1 00:00:00 1970 From: annie li Subject: Re: [PATCH 6/8] netfront: multi-page ring support Date: Thu, 28 Feb 2013 20:55:02 +0800 Message-ID: <512F53A6.4000401@oracle.com> References: <1360944010-15336-1-git-send-email-wei.liu2@citrix.com> <1360944010-15336-7-git-send-email-wei.liu2@citrix.com> <512C5B96.10204@oracle.com> <1361882139.2109.52.camel@zion.uk.xensource.com> <512DB83A.6050503@oracle.com> <1361980154.2109.67.camel@zion.uk.xensource.com> <512EE8EF.30200@oracle.com> <20130228110237.GA23777@zion.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "xen-devel@lists.xen.org" , "netdev@vger.kernel.org" , Ian Campbell , "konrad.wilk@oracle.com" To: Wei Liu Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:39477 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751265Ab3B1M4O (ORCPT ); Thu, 28 Feb 2013 07:56:14 -0500 In-Reply-To: <20130228110237.GA23777@zion.uk.xensource.com> Sender: netdev-owner@vger.kernel.org List-ID: On 2013-2-28 19:02, Wei Liu wrote: > On Thu, Feb 28, 2013 at 05:19:43AM +0000, ANNIE LI wrote: >> I checked the code in Konrad's tree and am thinking this overlap issue >> you mentioned existing in original netback(without multi-ring) and newer >> netfront. Original netback does not support multi-ring, and your newer >> netfront before this bug fix used "#define TX_MAX_TARGET >> XENNET_MAX_TX_RING_SIZE" directly. So that would cause overlap when >> netfront allocating rx skbs. >> "#define TX_MAX_TARGET min_t(int, NET_TX_RING_SIZE(1), 256)" limits the >> netfront to single ring, it fixed the overlap issue, but not enough. >> > Yes. I just saw a bug report from Xen-user list yesterday for the same > issue in original netback (1 page ring), so the overlap issue is not > introduced by multi-page ring implementation. If your team also sees that > issue, do you have patch to fix that? No. We thought your patch fixed it, and I did not check it further at that time. Are you sure they are same? What is the thread title in Xen-user? The overlap issue here exists in netfront when netfront allocates skb greedily. In Konrad's tree merged with your patch, netfront with "#define TX_MAX_TARGET XENNET_MAX_TX_RING_SIZE" should hit this overlap issue when it runs with single ring netback. Thanks Annie