Re: [RFT/RFC PATCH v3 4/5] arm: Use common cpu_topology

[Atish Patra]

On 4/15/19 8:31 AM, Sudeep Holla wrote:
> On Wed, Mar 20, 2019 at 04:48:05PM -0700, Atish Patra wrote:
> > Currently, ARM32 and ARM64 uses different data structures to
> > represent their cpu toplogies. Since, we are moving the ARM64
> > topology to common code to be used by other architectures, we
> > can reuse that for ARM32 as well.
> >
> > Signed-off-by: Atish Patra <atish.patra@xxxxxxx>
> > ---
> >   arch/arm/include/asm/topology.h | 22 +---------------------
> >   arch/arm/kernel/topology.c      | 10 +++++-----
> >   include/linux/arch_topology.h   | 10 +++++++++-
> >   3 files changed, 15 insertions(+), 27 deletions(-)
>
> [...]
>
> > diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h
> > index d4e76e0a..7c850611 100644
> > --- a/include/linux/arch_topology.h
> > +++ b/include/linux/arch_topology.h
> > @@ -36,17 +36,25 @@ unsigned long topology_get_freq_scale(int cpu)
> >   struct cpu_topology {
> >   	int thread_id;
> >   	int core_id;
> > +#ifdef CONFIG_ARM_CPU_TOPOLOGY
> > +	int socket_id;
>
> Sorry, but I can't find any reason why we need to do this ifdef dance
> here, especially for socket_id vs package_id ? 

I was not sure if we can rename socket_id to package_id from a semantic 
point of view. If you are okay with it, I will change it to package_id 
and send a v4.

Other's I can understand
> as there are new, but I am sure we can find a way and get away with
> #ifdefery here completely.
That would be good. Any suggestions on how to do that?

> > +#else
> >   	int package_id;
> >   	int llc_id;
> > +	cpumask_t llc_sibling;
> > +#endif
> >   	cpumask_t thread_sibling;
> >   	cpumask_t core_sibling;
> > -	cpumask_t llc_sibling;
> >   };
> >
> >   #ifdef CONFIG_GENERIC_ARCH_TOPOLOGY
> >   extern struct cpu_topology cpu_topology[NR_CPUS];
> >
> > +#ifdef CONFIG_ARM_CPU_TOPOLOGY
> > +#define topology_physical_package_id(cpu)	(cpu_topology[cpu].socket_id)
> > +#else
> >   #define topology_physical_package_id(cpu)	(cpu_topology[cpu].package_id)
> > +#endif
>
> Since all callsites must use topology_physical_package_id, we should be
> able to rename socket_id to package_id easily.
Sure.

Regards,
Atish
> --
> Regards,
> Sudeep