[LTP] [PATCH] controllers/cpuset_hotplug: skip unsupported Microsoft Hyper-V

[Krzysztof Kozlowski]

On 23/06/2021 15:34, Petr Vorel wrote:
> Hi Krzysztof,
> 
>> On 23/06/2021 11:35, Krzysztof Kozlowski wrote:
>>> On 23/06/2021 11:25, Petr Vorel wrote:
>>>> Hi Krzysztof,
> 
>>>>> Microsoft Hyper-V with Linux guests does not support CPU hotplug, even
>>>>> if enabled in kernel configuration.  Quoting Ubuntu bug report from
>>>>> June 2018: "While Hyper-V may present all potential CPUs via ACPI MADT,
>>>>> CPU add/remove is not supported.". [1]
> 
>>>> Reviewed-by: Petr Vorel <pvorel@suse.cz>
> 
>>>> LGTM. How many of tests will need tst_virt_hyperv? Although we don't touch
>>>> legacy API, I'd make an exception and add it to both test.sh and tst_test.sh
>>>> (ideally with an API extension, i.e. test could use SKIP_VIRT="hyperv", but that
>>>> can wait till tests are converted).
> 
>>> Around CPU hotplug that would be the last one I did not spot so far
>>> other failures but I also do not track all failures in nice way. Rather
>>> fixing them ad-hoc...
> 
>> I just checked more and there are additional failures on Azure/HyperV
>> with more nodes: cpuset_load_balance, cpuset_memory_pressure,
>> cpuset_memory_spread and cpuset_sched_domains. These did not appear on
>> smaller instances (e.g. 4 CPUs).
> 
> Good to know. Does it mean we should check number of processors?

No, it should be the same case as here, I just did not hit that test on
some of cloud instances (the tests are for CPU nodes > 1). I'll just
find a proper instance to try to reproduce it there.

> But even there were just these two and no additional change to
> tst_virt_hyperv(), we'd prefer to have them in test.sh and tst_test.sh.
> Could you please send v2, where you implement that?

I'll take a look.


Best regards,
Krzysztof