Another thing from the xen-users mailing list:
Apparently the way to specify the dom0 RAM at boot in Xen has changed. You should now specify the maximum memory – dom0_mem=2G,max:2G
instead of dom0_mem=2G
.
Also, a new addition to the Xen Best Practices suggests preventing Xen from auto-ballooning the dom0 memory down by changing autoballoon
in /etc/xen/xl.conf
to 0.