Re: [PATCH 1/2] viridian: remove implicit limit of 64 VPs per partition

[Igor Druzhinin <igor.druzhinin@xxxxxxxxxx>]

On 11/01/2021 13:47, Paul Durrant wrote:
>> -----Original Message-----
>> From: Jan Beulich <jbeulich@xxxxxxxx>
>> Sent: 11 January 2021 13:38
>> To: Igor Druzhinin <igor.druzhinin@xxxxxxxxxx>; paul@xxxxxxx
>> Cc: wl@xxxxxxx; iwj@xxxxxxxxxxxxxx; anthony.perard@xxxxxxxxxx; 
>> andrew.cooper3@xxxxxxxxxx;
>> george.dunlap@xxxxxxxxxx; julien@xxxxxxx; sstabellini@xxxxxxxxxx; 
>> roger.pau@xxxxxxxxxx; xen-
>> devel@xxxxxxxxxxxxxxxxxxxx
>> Subject: Re: [PATCH 1/2] viridian: remove implicit limit of 64 VPs per 
>> partition
>>
>> On 11.01.2021 14:34, Igor Druzhinin wrote:
>>> On 11/01/2021 09:16, Jan Beulich wrote:
>>>> On 11.01.2021 10:12, Paul Durrant wrote:
>>>>>> From: Paul Durrant <xadimgnik@xxxxxxxxx>
>>>>>> Sent: 11 January 2021 09:10
>>>>>>
>>>>>>> From: Jan Beulich <jbeulich@xxxxxxxx>
>>>>>>> Sent: 11 January 2021 09:00
>>>>>>>
>>>>>>> On 11.01.2021 09:45, Paul Durrant wrote:
>>>>>>>> You can add my R-b to the patch.
>>>>>>>
>>>>>>> That's the unchanged patch then, including the libxl change that
>>>>>>> I had asked about and that I have to admit I don't fully follow
>>>>>>> Igor's responses? I'm hesitant to give an ack for that aspect of
>>>>>>> the change, yet I suppose the libxl maintainers will defer to
>>>>>>> x86 ones there. Alternatively Andrew or Roger could of course
>>>>>>> ack this ...
>>>>>>>
>>>>>>
>>>>>> I don't think we really need specific control in xl.cfg as this is a fix 
>>>>>> for some poorly
>> documented
>>>>>> semantics in the spec. The flag simply prevents the leaf magically 
>>>>>> appearing on migrate and I
>> think
>>>>>> that's enough.
>>>>>
>>>>> ... although adding an option in xl/libxl isn't that much work, I suppose.
>>>>>
>>>>> Igor, would you be ok plumbing it through?
>>>>
>>>> This back and forth leaves unclear to me what I should do. I
>>>> would have asked on irc, but you're not there as it seems.
>>>
>>> I don't see a scenario where somebody would want to opt out of unlimited
>>> VPs per domain given the leaf with -1 is supported on all Windows versions.
>>
>> So Paul - commit patch as is then?
>>
>>> I can make it configurable in the future if reports re-surface it causes
>>> troubles somewhere.
>>
>> This is the slight concern I have: Having to make it configurable
>> once someone has reported trouble would look a little late to me.
>> Otoh I agree it may end up being dead code if no problems get
>> ever encountered.
>>
> 
> I think I'm persuaded by your caution. Since it's not a massive amount of 
> code, let's have flags for both wired through to xl and default them to on, 
> so I withdraw my R-b for the libxl_x86.c hunk.

Ok, will re-work the patches.

Igot