[libvirt] [PATCH] libxl: Add support for max_grant_frame setting

[Jim Fehlig]

On 3/5/19 3:17 AM, Daniel P. Berrangé wrote:
> On Mon, Mar 04, 2019 at 04:00:01PM -0700, Jim Fehlig wrote:
>> Xen 4.10 introduced the max_grant_frames xl config setting, which
>> can be set globally in xl.conf(5) or per-domain in xl.cfg(5).
>> max_grant_frames specifies the maximum number of grant frames the
>> domain is allowed to have, which in turn controls the number of
>> pages the domain can share.
> 
> Does the grant frame value have any impact on the live migration
> compatibility ? ie if both source and dest host are required to
> have identical grant frame values, then it is preferrable to /not/
> have this as a host tunable, but only as XML.  You generally don't
> want anything affecting mig compatibility in host level configs.

Thanks for the reminder. Yes, grant frame value could have an affect on 
migration. I didn't put much thought into it since Xen has a similar concept in 
their host level config. Difference is, they also support the setting in their 
per-domain config.

So I'm back to figuring out how to model this in XML

https://www.redhat.com/archives/libvir-list/2019-February/msg01218.html

Your opinion would be much appreciated! Thus far my preferred option is the last 
one described in that thread

https://www.redhat.com/archives/libvir-list/2019-March/msg00124.html

Regards,
Jim