Re: [PATCH v3] sched/topology: Enable topology_span_sane check only for debug builds

K Prateek Nayak
2025-02-05T10:14:10Z

Hello Peter,

Thank you for the background!

On 2/5/2025 3:25 PM, Peter Zijlstra wrote:
> On Wed, Feb 05, 2025 at 03:18:24PM +0530, K Prateek Nayak wrote:
>
>> Have there been any reports on an x86 system / VM where
>> topology_span_sane() was tripped?
>
> At the very least Intel SNC 'feature' tripped it at some point. They
> figured it made sense to have the LLC span two nodes.
>
> But I think there were some really dodgy VMs too.
>
> But yeah, its not been often. But basically dodgy BIOS/VM data can mess
> up things badly enough for it to trip.

Has it ever happened without tripping the topology_sane() check first
on the x86 side?

--
Thanks and Regards,
Prateek