From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yang Hongyang <yanghy@cn.fujitsu.com>
Subject: Re: [PATCH v2 COLOPre 10/13] tools/libxl: Add back
 channel to allow migration target send data back
Date: Mon, 15 Jun 2015 09:38:55 +0800
Message-ID: <557E2CAF.3060505@cn.fujitsu.com>
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To: Ian Jackson <Ian.Jackson@eu.citrix.com>, Wei Liu <wei.liu2@citrix.com>
Cc: ian.campbell@citrix.com, wency@cn.fujitsu.com, andrew.cooper3@citrix.com, yunhong.jiang@intel.com, eddie.dong@intel.com, xen-devel@lists.xen.org, guijianfeng@cn.fujitsu.com, rshriram@cs.ubc.ca
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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 <wency@cn.fujitsu.com>
>>>
>>> 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().

>
> 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.
> .
>

-- 
Thanks,
Yang.