Hi,

On 06/05/2018 10:27 AM, Sudeep Holla wrote:

On 05/06/18 16:02, Rafael J. Wysocki wrote:

quoted

On Tue, Jun 5, 2018 at 4:35 PM, Sudeep Holla [off-list ref] wrote:

quoted

Currently, ARM64 doesn't support updating the CPU topology masks on
CPU hotplug operations. ACPI PPTT support rely on that missing feature
which is technically not incorrect. Instead of reverting all the PPTT
support, let's keep it simple and disable ACPI PPTT support on ARM64
for time-being until the topology updates are added for CPU hotplug
operations.

When is that going to happen?

quoted

Nobody else uses PPTT now.

No we need it on ARM64. I have even the fixes for the original issue
but it's bit invasive and too late as we are already in the merge
window. It needs to be tested on NUMA platforms, I have asked for that
explicitly.

So, there is a lot simpler fix for this, and its to remove the numa mask 
dependency from the scheduler domain building. That is just a couple 
line fix, and it reverts !ACPI to its original behavior, while the ACPI 
LLC building will work around the NUMA in package issue that caused 
patch 12/12 as the machine in question doesn't have a LLC crossing numa 
domains.