At the moment we are using dom0_mem=3G,max:3G for example (where dom0 mem and max values are the same). So we just need to allow a slightly higher max value to leave some ballooned pages? The Xen4centos documentation also says to use the same value for dom0_mem and max. Thanks Chris _____ ________________________________________ From: David Vrabel [david.vrabel@xxxxxxxxxx] Sent: 08 January 2014 13:12 To: Discussion about the virtualization on CentOS Cc: Chris Elliott Subject: Re: xen_balloon: reserve_additional_memory: add_memory() Errors On 03/01/14 19:58, Chris Elliott wrote: > Hi All > > > > Back in August there was a report of these errors popping up in dmesg, > and as far as I can tell it’s still unresolved even in the latest kernel. > > System RAM resource [mem 0xc8000000-0xcfffffff] cannot be added > xen_balloon: reserve_additional_memory: add_memory() failed: -17 Drivers (e.g., blkback) use ballooned pages for use for foreign mappings. Depending on dom0_mem options there may be no ballooned memory available at boot and dom0's balloon is increased by allocating pages. This decreases current_kb. The balloon driver then tries to decrease the balloon to match the target but it can only do this by hotplugging new memory. A bug in the balloon driver means the location of this memory overlaps with an address range that is already in use and the hotplug will fail. As a workaround you can boot dom0 with a suitable amount of pre-ballooned memory with: dom0_mem=3G,max:4G You may need to experiment with the max: value. David _______________________________________________ CentOS-virt mailing list CentOS-virt@xxxxxxxxxx http://lists.centos.org/mailman/listinfo/centos-virt
