From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH v2 COLOPre 10/13] tools/libxl: Add back channel to allow migration target send data back Date: Tue, 16 Jun 2015 11:52:17 +0100 Message-ID: <1434451937.13744.99.camel@citrix.com> References: <1433734997-26570-1-git-send-email-yanghy@cn.fujitsu.com> <1433734997-26570-11-git-send-email-yanghy@cn.fujitsu.com> <20150612125429.GO14606@zion.uk.xensource.com> <21882.62720.890610.633137@mariner.uk.xensource.com> <557E2CAF.3060505@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <557E2CAF.3060505@cn.fujitsu.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Yang Hongyang Cc: Wei Liu , eddie.dong@intel.com, wency@cn.fujitsu.com, andrew.cooper3@citrix.com, yunhong.jiang@intel.com, Ian Jackson , xen-devel@lists.xen.org, guijianfeng@cn.fujitsu.com, rshriram@cs.ubc.ca List-Id: xen-devel@lists.xenproject.org On Mon, 2015-06-15 at 09:38 +0800, Yang Hongyang wrote: > > On 06/12/2015 11:04 PM, Ian Jackson wrote: > > Wei Liu writes ("Re: [Xen-devel] [PATCH v2 COLOPre 10/13] tools/libxl: Add back channel to allow migration target send data back"): > >> On Mon, Jun 08, 2015 at 11:43:14AM +0800, Yang Hongyang wrote: > >>> From: Wen Congyang > >>> > >>> In colo mode, slave needs to send data to master, but the io_fd > >>> only can be written in master, and only can be read in slave. > >>> Save recv_fd in domain_suspend_state, and send_fd in > >>> domain_create_state. > > ... > >>> libxl_domain_restore_params = Struct("domain_restore_params", [ > >>> ("checkpointed_stream", integer), > >>> + ("send_fd", integer), > >> > >> I'm not entirely sure if we want to bury an extra argument here. > >> > >> After looking at code I think you're trying to work around API > >> limitation. I think we are safe to extend the API -- we've already done > >> that before. See libxl.h around line 990. > >> > >> Ian and Ian, what do you think? > > > > I agree with you, Wei. I don't think an fd should be in > > libxl_domain_restore_params at all. > > Then I'll just extend the params of libxl_domain_create_restore(). One question first: is it really to be expected that send_fd and recv_fd will be different, as opposed to the bidirectional data going over the same socket? > > > > > We need to understand what the API semantics are. Are are going to > > introduce a new libxl API entrypoint ? We already have > > libxl_domain_remus_start. > > We use libxl_domain_remus_start for COLO. COLO is an option of "xl remus". > > > > > Ian. > > . > > >