[CentOS-virt] xen_balloon: reserve_additional_memory: add_memory() Errors
David Vrabel
david.vrabel at citrix.com
Wed Jan 8 13:12:40 UTC 2014
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
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