RE: [XEN RFC PATCH 07/40] xen/arm: use !CONFIG_NUMA to keep fake NUMA API

[Wei Chen <Wei.Chen@xxxxxxx>]

Hi Julien,

> -----Original Message-----
> From: Julien Grall <julien@xxxxxxx>
> Sent: 2021年8月19日 21:34
> To: Wei Chen <Wei.Chen@xxxxxxx>; xen-devel@xxxxxxxxxxxxxxxxxxxx;
> sstabellini@xxxxxxxxxx; jbeulich@xxxxxxxx
> Cc: Bertrand Marquis <Bertrand.Marquis@xxxxxxx>
> Subject: Re: [XEN RFC PATCH 07/40] xen/arm: use !CONFIG_NUMA to keep fake
> NUMA API
> 
> Hi Wei,
> 
> On 11/08/2021 11:23, Wei Chen wrote:
> > Only Arm64 supports NUMA, the CONFIG_NUMA could not be
> > enabled for Arm32.
> 
> What do you mean by "could not be enabled"?

I have not seen any Arm32 hardware support NUMA, so I think
we don't need to support Arm32 NUMA. In this case, this Kconfig
option could not be enabled on Arm32.

> 
> > Even in Arm64, users still can disable
> > the CONFIG_NUMA through Kconfig option. In this case, keep
> > current fake NUMA API, will make Arm code still can work
> > with NUMA aware memory allocation and scheduler.
> >
> > Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
> > ---
> >   xen/include/asm-arm/numa.h | 4 ++++
> >   1 file changed, 4 insertions(+)
> >
> > diff --git a/xen/include/asm-arm/numa.h b/xen/include/asm-arm/numa.h
> > index 31a6de4e23..ab9c4a2448 100644
> > --- a/xen/include/asm-arm/numa.h
> > +++ b/xen/include/asm-arm/numa.h
> > @@ -5,6 +5,8 @@
> >
> >   typedef u8 nodeid_t;
> >
> > +#if !defined(CONFIG_NUMA)
> 
> NIT: We tend to use #ifndef rather than #if !defined(...)
> 

OK, I will change related changes in this series.

> > +
> >   /* Fake one node for now. See also node_online_map. */
> >   #define cpu_to_node(cpu) 0
> >   #define node_to_cpumask(node)   (cpu_online_map)
> > @@ -25,6 +27,8 @@ extern mfn_t first_valid_mfn;
> >   #define node_start_pfn(nid) (mfn_x(first_valid_mfn))
> >   #define __node_distance(a, b) (20)
> >
> > +#endif
> > +
> >   #endif /* __ARCH_ARM_NUMA_H */
> >   /*
> >    * Local variables:
> >
> 
> Cheers,
> 
> --
> Julien Grall