search for: preballooned

...amount > of memory. On a modern dom0 kernel you need to specify the maximum memory as well, i.e. dom0_mem=8192M,max:8192M otherwise the kernel will attempt to allocate enough page tables to cover all of *host* RAM which can exhaust its actual memory allocation. You can of course also boot "preballooned" e.g. dom0_mem=1G,max:4G but need to be mindful of the ratio between the two. http://blog.xen.org/index.php/2012/04/30/memory-where-it-has-not-gone/ has some background discussion. Ian.

Package: xen-hypervisor-4.1-amd64 Version: 4.1.4-3+deb7u1 Severity: normal I tried GRUB_CMDLINE_XEN="dom0_mem=8192M": that delivers 6964868K total, then crashes when used=2837436K free=4127432K. By crash I mean the gnome screen was blown away, replaced by a black screen with white log lines. That seems to happen every time dom0 uses a large amount of memory. After setting