Hi Julien,
> -----Original Message-----
> From: Julien Grall <jul...@xen.org>
> Sent: 2021年8月27日 22:09
> To: Wei Chen <wei.c...@arm.com>; xen-devel@lists.xenproject.org;
> sstabell...@kernel.org; jbeul...@suse.com
> Cc: Bertrand Marquis <bertrand.marq...@arm.com>
> Subject: Re: [XEN RFC PATCH 32/40] xen/x86: make acpi_scan_nodes to be
> neutral
>
> Hi Wei,
>
> On 11/08/2021 11:24, Wei Chen wrote:
> > The code in acpi_scan_nodes can be reused for device tree based
> > NUMA. So we rename acpi_scan_nodes to numa_scan_nodes for a neutral
> > function name. As acpi_numa variable is available in ACPU based NUMA
> > system only, we use CONFIG_ACPI_NUMA to protect it.
> >
> > Signed-off-by: Wei Chen <wei.c...@arm.com>
> > ---
> > xen/arch/x86/srat.c | 4 +++-
> > xen/common/numa.c | 2 +-
> > xen/include/asm-x86/acpi.h | 2 +-
> > 3 files changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/xen/arch/x86/srat.c b/xen/arch/x86/srat.c
> > index dcebc7adec..3d4d90a622 100644
> > --- a/xen/arch/x86/srat.c
> > +++ b/xen/arch/x86/srat.c
> > @@ -362,7 +362,7 @@ void __init srat_parse_regions(u64 addr)
> > }
> >
> > /* Use the information discovered above to actually set up the nodes.
> */
> > -int __init acpi_scan_nodes(u64 start, u64 end)
> > +int __init numa_scan_nodes(u64 start, u64 end)
> > {
> > int i;
> > nodemask_t all_nodes_parsed;
> > @@ -371,8 +371,10 @@ int __init acpi_scan_nodes(u64 start, u64 end)
> > for (i = 0; i < MAX_NUMNODES; i++)
> > cutoff_node(i, start, end);
> >
> > +#ifdef CONFIG_ACPI_NUMA
> > if (acpi_numa <= 0)
> > return -1;
> > +#endif
>
> Looking at the follow-up patches, I find a bit odd that there is a check
> for ACPI but there is none added for DT. Can you explain why?
>
Oh, I forgot DT check. And simply to add DT check here seems not a
good idea. Because once, when Arm support ACPI NUMA.
CONFIG_ACPI_NUMA and CONFIG_DEVICE_TREE_NUMA can be selected at
the same time. But only acpi_numa or dtb_numa can be > 0.
> However, I think this check is going to impair the work to support both
> ACPI and DT on Arm because acpi_numa would end up to be 0 so you would
> bail out here.
>
> With that in mind, I think this check needs to either go away or replace
> by something there is firmware agnostic.
Yes, we have discussed about something like fw_numa before.
>
> Cheers,
>
> --
> Julien Grall
