From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by dpdk.org (Postfix) with ESMTP id 2B1732C08 for ; Tue, 5 Apr 2016 16:05:44 +0200 (CEST) Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga103.jf.intel.com with ESMTP; 05 Apr 2016 07:05:04 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,444,1455004800"; d="scan'208";a="778477781" Received: from yliu-dev.sh.intel.com (HELO yliu-dev) ([10.239.67.191]) by orsmga003.jf.intel.com with ESMTP; 05 Apr 2016 07:05:03 -0700 Date: Tue, 5 Apr 2016 22:06:33 +0800 From: Yuanhan Liu To: Thomas Monjalon Cc: dev@dpdk.org, Ilya Maximets , Dyasly Sergey , Flavio Leitner , "Xie, Huawei" Message-ID: <20160405140633.GP3080@yliu-dev.sh.intel.com> References: <1455863563-15751-1-git-send-email-i.maximets@samsung.com> <20160219070650.GS21426@yliu-dev.sh.intel.com> <20160405054733.GO3080@yliu-dev.sh.intel.com> <1865360.UqzrcfEKI5@xps13> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1865360.UqzrcfEKI5@xps13> User-Agent: Mutt/1.5.23 (2014-03-12) Subject: Re: [dpdk-dev] [RFC] vhost-user public struct refactor (was Re: [PATCH RFC 2/4] vhost: make buf vector for scatter RX) local. X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 05 Apr 2016 14:05:44 -0000 On Tue, Apr 05, 2016 at 10:37:13AM +0200, Thomas Monjalon wrote: > 2016-04-05 13:47, Yuanhan Liu: > > So, I was considering to add vhost-user Tx delayed-copy (or zero copy) > > support recently, which comes to yet another ABI violation, as we need > > add a new field to virtio_memory_regions struct to do guest phys addr > > to host phys addr translation. You may ask, however, that why do we need > > expose virtio_memory_regions struct to users at all? > > > > You are right, we don't have to. And here is the thing: we exposed way > > too many fields (or even structures) than necessary. Say, vhost_virtqueue > > struct should NOT be exposed to user at all: application just need to > > tell the right queue id to locate a specific queue, and that's all. > > The structure should be defined in an internal header file. With that, > > we could do any changes to it we want, without worrying about that we > > may offense the painful ABI rules. > > > > Similar changes could be done to virtio_net struct as well, just exposing > > very few fields that are necessary and moving all others to an internal > > structure. > > > > Huawei then suggested a more radical yet much cleaner one: just exposing > > a virtio_net handle to application, just like the way kernel exposes an > > fd to user for locating a specific file. However, it's more than an ABI > > change; it's also an API change: some fields are referenced by applications, > > such as flags, virt_qp_nb. We could expose some new functions to access > > them though. > > > > I'd vote for this one, as it sounds very clean to me. This would also > > solve the block issue of this patch. Though it would break OVS, I'm thinking > > that'd be okay, as OVS has dependence on DPDK version: what we need to > > do is just to send few patches to OVS, and let it points to next release, > > say DPDK v16.07. Flavio, please correct me if I'm wrong. > > > > Thoughts/comments? > > Do you plan to send a deprecation notice to change API in 16.07? Yes, I planned to, shortly. Before that, I'd ask for comments first. --yliu