[libvirt] [Qemu-devel] [PATCH V17 02/11] NUMA: check if the total numa memory size is equal to ram_size

[Eduardo Habkost]

On Tue, Dec 10, 2013 at 07:03:50PM +0100, Paolo Bonzini wrote:
> Il 10/12/2013 14:15, Eduardo Habkost ha scritto:
> >> > If the total number of the assigned numa nodes memory is not
> >> > equal to the assigned ram size, it will write the wrong data
> >> > to ACPI talb, then the guest will ignore the wrong ACPI table
> >> > and recognize all memory to one node. It's buggy, we should
> >> > check it to ensure that we write the right data to ACPI table.
> >> > 
> >> > Signed-off-by: Wanlong Gao <gaowanlong at cn.fujitsu.com>
> > This will make configurations that could be running for years (except
> > that the guest OS was ignoring the NUMA data) suddenly stop running. I
> > just want to confirm: we really want that, right?
> > 
> > Does libvirt allow this kind of broken configuration to be generated, or
> > it already ensures the total NUMA node sizes match RAM size?
> 
> It allows this.  It just converts the <numa> XML to "-numa node".

In that case, if we apply this patch we may want to make libvirt
validate the NUMA configuration instead of getting a cryptic "QEMU
aborted" error message with the actual problem buried in a log file.

(Well, even if we do not apply this patch, I believe it is a good idea to
make libvirt validate the NUMA configuration.)

-- 
Eduardo