[PATCH 5/5] qemu_validate.c: revert NUMA CPU range user warning

Daniel Henrique Barboza danielhb413 at gmail.com
Mon Jun 1 20:14:20 UTC 2020



On 6/1/20 4:40 PM, Peter Krempa wrote:
> On Mon, Jun 01, 2020 at 14:50:41 -0300, Daniel Henrique Barboza wrote:
>> Now that we have the auto-fill code in place, and with proper documentation
>> to let the user know that (1) we will auto-fill the NUMA cpus up to the
>> number to maximum VCPUs number if QEMU supports it and (2) the user
>> is advised to always supply a complete NUMA topology, this warning
>> is unneeded.
>>
>> This reverts commit 38d2e033686b5cc274f8f55075ce1985b71e329a.
> 
> Since we already have the validation in place for some time now I think
> we should just keep it. The auto-filling would be a useful hack to work
> around if config breaks, but judged by itself it's of questionable
> benefit.

That's a good point. I agree that removing the message after being in place
for this long is more trouble than it's worth.

> 
> Specifically users might end up with a topology which they didn't
> expect. Reasoning is basically the same as with qemu. Any default
> behaviour here is a policy decision and it might not suit all uses.
>

  
An ideal situation would be QEMU to never accept incomplete NUMA topologies
in the first place.

Given that this wasn't the case and now there might be a plethora of guests
running with goofy topologies all around, the already existing warning
message + this auto-fill hack + documentation mentioning that users should
avoid these topologies is a fine solution from Libvirt side, in my
estimation.


Thanks,


DHB




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