Comment # 3 on bug 1037985 from James Fehlig

> Alternatively you could boot with "dom0_mem=<amount>" on the Xen command
> line, to avoid the need for any ballooning.

@John: FYI, this is the recommended configuration. See "4.1.3 Xen-specific
Memory Notes" in the VT best practices doc

https://www.suse.com/documentation/sles-12/singlehtml/vt_best_practices_guide/vt_best_practices_guide.html#sec.vt.best.hostlevel