On Fri, Jan 12, 2007 at 02:42:13PM +0100, Philippe Berthault wrote: > Daniel P. Berrange a écrit : > >On Fri, Jan 12, 2007 at 11:47:16AM +0100, Philippe Berthault wrote: > > > >>The maxMem field of the virDomainInfo structure is given in bytes > >>instead of Kbytes when the domain is 0 (Domain-0). With others domains, > >>the value of maxMem is correct. > >> > >>Exemple with virsh: > >> On a system with 4 GB memory, virsh reports: > >> # virsh dominfo 0 > >> ... > >> Max memory: 4294967292 kB > >> > >>With the same libvirt version 0.1.9 but with an older Xen (not 3.0.3), > >>the maxMem value of Domain-0 is correct. > >> > > > >This sounds like a bug in Xen, rather than a bug in libvirt - we don't > >have any special handling for Domain-0 - we're just passing back through > >whatever data we get from Xen. > > > >Dan. > > > This problem seems to be caused by a missing initialization (in Xen or > libvirt ? to be determined) because after setting the system memory size > by using the "xm mem-max" command on Domain-0, the Max memory value > returned by virsh is correct and reflect the value passed to the xm command. > > This problem of incoherent maxMem value on Domain-0 has been detected > after a system reboot. I think Xen just returns -1 when the field is uninitialized, probably meaning 'all physical memory'. Once you use "xm mem-max 0 ..." then it consider the Dom0 domain constrained, but not before. And since there are machine where it's possible to hot plug new memory this is a way to not poll the current physical memory, a bit weird but that can be understood. Daniel -- Red Hat Virtualization group http://redhat.com/virtualization/ Daniel Veillard | virtualization library http://libvirt.org/ veillard@xxxxxxxxxx | libxml GNOME XML XSLT toolkit http://xmlsoft.org/ http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/