From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Jackson <Ian.Jackson@eu.citrix.com>
Subject: Re: [PATCH v6 COLO 02/15] secondary vm
 suspend/resume/checkpoint code
Date: Tue, 16 Jun 2015 12:42:36 +0100
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To: Yang Hongyang <yanghy@cn.fujitsu.com>
Cc: Wei Liu <wei.liu2@citrix.com>, 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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Yang Hongyang writes ("Re: [Xen-devel] [PATCH v6 COLO 02/15] secondary vm suspend/resume/checkpoint code"):
> > On Mon, Jun 08, 2015 at 11:45:46AM +0800, Yang Hongyang wrote:
...
> >> 3. Suspend secondary vm
> >>     a. Suspend secondary vm.
> >>     b. Call libxl__checkpoint_devices_postsuspend().
> >>     c. Get secondary vm's dirty page information.
> >>     d. Send LIBXL_COLO_SVM_SUSPENDED to master.
> >>     e. Send secondary vm's dirty page information to master(count + pfn list).

In the pdf
   http://www.socc2013.org/home/program/a3-dong.pdf?attredirects=0
linked from the wiki page
   http://wiki.xen.org/wiki/COLO_-_Coarse_Grain_Lock_Stepping
it says that the secondary keeps a copy of the original contents of
its dirty pages.  So I don't understand why you need to send the dirty
bitmap to the primary.

Thanks,
Ian.