RE: [PATCH 06/32] x86/intel_rdt: Hot cpu support for Cache Allocation

[Yu, Fenghua]

> 
> > +static inline void intel_rdt_cpu_start(int cpu) {
> > +       struct intel_pqr_state *state = &per_cpu(pqr_state, cpu);
> > +
> > +       state->closid = 0;
> > +       mutex_lock(&rdt_group_mutex);
> > +       if (rdt_cpumask_update(cpu))
> > +               smp_call_function_single(cpu, cbm_update_msrs, NULL, 1);
> > +       mutex_unlock(&rdt_group_mutex);
> 
> what happens if cpu's with a cache_id not available at boot comes online?

For L3, that case happens when a new socket is hot plugged into the platform.
We don't handle that right now because that needs platform support and I don't
have that kind of platform to test.

But maybe I can add that support in code and do a test in a simulated mode.
Basically that will create a new domain for the new cache_id.

Thanks.

-Fenghua