Re: [PATCH v3 COLOPre 16/26] tools/libx{l, c}: add back channel to libxc

[Yang Hongyang <yanghy@cn.fujitsu.com>]

On 06/30/2015 06:10 PM, Ian Campbell wrote:
> On Thu, 2015-06-25 at 14:25 +0800, Yang Hongyang wrote:
>> We need to send secondary's dirty page pfns back to primary.
>
> In v2 Ian asked (<21888.2988.774072.32946@mariner.uk.xensource.com>):
>
>          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.
>
> Which I don't see an answer for in my archive. Have I missed (or
> misplaced) the answer?

Sorry, seems that I misplaced the answer to:
[PATCH v2 COLOPre 09/13] tools/libxl: Update libxl_save_msgs_gen.pl to support 
return data from xl to xc

   > Thanks for this.  I would have some comments on the details, but first
   > I want to properly understand your use case.  So while I'm the author
   > and maintainer of this save helper, I won't review this in detail just
   > yet.  I'm following the thread about what this is for...

     We need to send secondary's dirty page pfn back to primary. Primary will
     then send pages that are both dirtied on primary/secondary to secondary.
     in this way the secondary's memory will be consistent with primary.

     As we disscussed in [PATCH v2 COLOPre 04/13] tools/libxc: export xc_bitops.h
     If we move this operation to libxc layer, this patch could be dropped.

>
> Ian
>
> .
>

-- 
Thanks,
Yang.