[libvirt] [PATCH] virsh: Fix docs for "virsh setmaxmem"

[Peter Krempa]

On 03/22/13 22:01, Eric Blake wrote:
> On 03/22/2013 04:08 AM, Peter Krempa wrote:
>> The docs assumed the command works always for QEMU and other
>> hypervisors. Unfortunately until qemu will add memory hotplug
>> this can't be done. Fix the docs to mention this limitation.
>
> The setmaxmem command controls balloon size, not memory hotplug.  If
> qemu adds memory hotplug, we STILL have to pre-declare a maximum memory
> size when qemu first boots, and at runtime, you can only change the
> current memory.  And if we do add qemu memory hotplug support (and not
> just memory ballooning), I'm not sure if it would make sense to reuse
> the setmaxmem command (probably with a new flag) or add a new command.

I agree, the commit message was a bit misleading. The question of memory 
hotplug will have to remain open until qemu will actually support it. I 
removed the note about hotplug from the commit message.


>
>> ---
>>   tools/virsh.pod | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>
>>
>> -This command works for at least the Xen, QEMU/KVM and vSphere/ESX hypervisors.
>> +Some hypervisors such as QEMU/KVM don't support live changes (especially
>> +increasing) of the maximum memory limit.
>
> I don't know of any hypervisor that supports changing the maximum limit
> on a live domain - the maximum is pinned when the hypervisor starts, and
> can only be changed for the next boot.
>
> At any rate, while this wording might not be the best possible, it is
> certainly an improvement, so:

Well yes. I thought about it a bit more, the wording isn't ideal but 
definitely better than it was before, so ...

>
> ACK.
>

I pushed this patch. Thanks.

Peter