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

From: K Prateek Nayak
Date: Wed Feb 05 2025 - 05:16:37 EST


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