problem when checkpoint a running domain

problem when checkpoint a running domain

[ANNIE LI]

Hi

When using "xm save -c" to checkpoint a running domain, the hypercall 
SHUTDOWN_suspend should return 1, right?
However, it return 0 in my winpv driver. And i did not pass start_info 
as a parameter to the hypercall, is it necessary to write the magic word 
in start_info and then pass it as a parameter to suspend hypercall to 
support "xm save -c"?
There is also a suspend-cancel key in xenstore, and it's value is 1. 
What is it for? Need i do some process with this xenstore key?

Thanks
Annie.

Re: problem when checkpoint a running domain

[Keir Fraser]

On 16/09/2009 00:45, "ANNIE LI" <annie.li@oracle.com> wrote:

> When using "xm save -c" to checkpoint a running domain, the hypercall
> SHUTDOWN_suspend should return 1, right?

Yes. The bit of code of interest here is in
tools/python/xen/xend/XendDomainInfo.py -- search for 'fast =
self.info.get_notes().get('SUSPEND_CANCEL') and 1 or 0', and the following
code up to 'xc.domain_resume(self.domid, fast)'. For suspend cancellation to
work right you should be seeing fast=1. And that gets passed to
xc_domain_resume() in tools/libxc/xc_resume.c. So you should be able to
follow that code through and debug what's happening.

> However, it return 0 in my winpv driver. And i did not pass start_info
> as a parameter to the hypercall, is it necessary to write the magic word
> in start_info and then pass it as a parameter to suspend hypercall to
> support "xm save -c"?

No, the argument to HYPERVISOR_suspend() is unused for HVM guests -- you can
just pass zero.

> There is also a suspend-cancel key in xenstore, and it's value is 1.
> What is it for? Need i do some process with this xenstore key?

No. It indicates that the xend assumes all PV-on-HVM drivers support suspend
cancellation.

 -- Keir

Re: problem when checkpoint a running domain

[ANNIE LI]

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Thank you very much.
Will do that as you suggested.

Thanks
Annie.

Keir Fraser wrote:
> On 16/09/2009 00:45, "ANNIE LI" <annie.li@oracle.com> wrote:
>
>   
>> When using "xm save -c" to checkpoint a running domain, the hypercall
>> SHUTDOWN_suspend should return 1, right?
>>     
>
> Yes. The bit of code of interest here is in
> tools/python/xen/xend/XendDomainInfo.py -- search for 'fast =
> self.info.get_notes().get('SUSPEND_CANCEL') and 1 or 0', and the following
> code up to 'xc.domain_resume(self.domid, fast)'. For suspend cancellation to
> work right you should be seeing fast=1. And that gets passed to
> xc_domain_resume() in tools/libxc/xc_resume.c. So you should be able to
> follow that code through and debug what's happening.
>
>   
>> However, it return 0 in my winpv driver. And i did not pass start_info
>> as a parameter to the hypercall, is it necessary to write the magic word
>> in start_info and then pass it as a parameter to suspend hypercall to
>> support "xm save -c"?
>>     
>
> No, the argument to HYPERVISOR_suspend() is unused for HVM guests -- you can
> just pass zero.
>
>   
>> There is also a suspend-cancel key in xenstore, and it's value is 1.
>> What is it for? Need i do some process with this xenstore key?
>>     
>
> No. It indicates that the xend assumes all PV-on-HVM drivers support suspend
> cancellation.
>
>  -- Keir
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>   

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