Re: [PATCH v3] ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512

[Catalin Marinas]

On Tue, Mar 12, 2024 at 10:06:06AM -0700, Christoph Lameter (Ampere) wrote:
> On Mon, 11 Mar 2024, Christoph Lameter (Ampere) wrote:
> 
> > This could be an issue in the ARM64 arch code itself where there maybe
> > an assumption elsewhere that a cpumask can always store up to NR_CPU
> > cpus and not only nr_cpu_ids as OFFSTACK does.
> > 
> > How can I exercise the opp driver in order to recreate the problem?
> > 
> > I assume the opp driver is ARM specific? x86 defaults to OFFSTACK so if
> > there is an issue with OFFSTACK in opp then it should fail with kernel
> > default configuration on that platform.
> 
> I checked the ARM64 arch sources use of NR_CPUS and its all fine.
> 
> Also verified in my testing logs that CONFIG_PM_OPP was set in all tests.
> 
> No warnings in the kernel log during those tests.
> 
> How to reproduce this?

I guess you need a platform with a dts that has an "operating-points-v2"
property. I don't have any around.

Sudeep was trying to trigger this code path earlier, not sure where he
got to.

-- 
Catalin