Re: [PATCH v2 3/6] powerpc/smp: Move shared_processor static key to smp.h

Srikar Dronamraju
2023-10-19T13:10:19Z

* Michael Ellerman <mpe@ellerman.id.au> [2023-10-19 15:41:40]:

> Srikar Dronamraju <srikar@linux.vnet.ibm.com> writes:
> > The ability to detect if the system is running in a shared processor
> > mode is helpful in few more generic cases not just in
> > paravirtualization.
> > For example: At boot time, different scheduler/ topology flags may be
> > set based on the processor mode. Hence move it to a more generic file.
>
> I'd rather you just included paravirt.h in the few files where you need it.

I thought, detecting if a Processor was shared or not was more a
smp/processor related than a paravirt related.

Will drop as suggested.

>
> cheers
>
> > diff --git a/arch/powerpc/include/asm/paravirt.h b/arch/powerpc/include/asm/paravirt.h
> > index 0372b0093f72..cf83e837a571 100644
> > --- a/arch/powerpc/include/asm/paravirt.h
> > +++ b/arch/powerpc/include/asm/paravirt.h
> > @@ -15,13 +15,6 @@
> > #include <asm/kvm_guest.h>
> > #include <asm/cputhreads.h>
> >
> > -DECLARE_STATIC_KEY_FALSE(shared_processor);
> > -
> > -static inline bool is_shared_processor(void)
> > -{
> > - return static_branch_unlikely(&shared_processor);
> > -}
> > -
> > #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
> > extern struct static_key paravirt_steal_enabled;
> > extern struct static_key paravirt_steal_rq_enabled;
> > @@ -77,11 +70,6 @@ static inline bool is_vcpu_idle(int vcpu)
> > return lppaca_of(vcpu).idle;
> > }
> > #else
> > -static inline bool is_shared_processor(void)
> > -{
> > - return false;
> > -}
> > -
> > static inline u32 yield_count_of(int cpu)
> > {
> > return 0;
> > diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
> > index aaaa576d0e15..08631b2a4528 100644
> > --- a/arch/powerpc/include/asm/smp.h
> > +++ b/arch/powerpc/include/asm/smp.h
> > @@ -34,6 +34,20 @@ extern bool coregroup_enabled;
> > extern int cpu_to_chip_id(int cpu);
> > extern int *chip_id_lookup_table;
> >
> > +#ifdef CONFIG_PPC_SPLPAR
> > +DECLARE_STATIC_KEY_FALSE(shared_processor);
> > +
> > +static inline bool is_shared_processor(void)
> > +{
> > + return static_branch_unlikely(&shared_processor);
> > +}
> > +#else
> > +static inline bool is_shared_processor(void)
> > +{
> > + return false;
> > +}
> > +#endif
> > +
> > DECLARE_PER_CPU(cpumask_var_t, thread_group_l1_cache_map);
> > DECLARE_PER_CPU(cpumask_var_t, thread_group_l2_cache_map);
> > DECLARE_PER_CPU(cpumask_var_t, thread_group_l3_cache_map);
> > --
> > 2.31.1

--
Thanks and Regards
Srikar Dronamraju