On Mon, 27 Sep 2021, 10:33 Jan Beulich, <jbeul...@suse.com> wrote: > On 24.09.2021 21:39, Stefano Stabellini wrote: > > On Fri, 24 Sep 2021, Wei Chen wrote: > >> On 2021/9/24 11:31, Stefano Stabellini wrote: > >>> On Thu, 23 Sep 2021, Wei Chen wrote: > >>>> --- a/xen/arch/arm/Kconfig > >>>> +++ b/xen/arch/arm/Kconfig > >>>> @@ -34,6 +34,17 @@ config ACPI > >>>> Advanced Configuration and Power Interface (ACPI) support for > Xen is > >>>> an alternative to device tree on ARM64. > >>>> + config DEVICE_TREE_NUMA > >>>> + def_bool n > >>>> + select NUMA > >>>> + > >>>> +config ARM_NUMA > >>>> + bool "Arm NUMA (Non-Uniform Memory Access) Support (UNSUPPORTED)" > if > >>>> UNSUPPORTED > >>>> + select DEVICE_TREE_NUMA if HAS_DEVICE_TREE > >>> > >>> Should it be: depends on HAS_DEVICE_TREE ? > >>> (And eventually depends on HAS_DEVICE_TREE || ACPI) > >>> > >> > >> As the discussion in RFC [1]. We want to make ARM_NUMA as a generic > >> option can be selected by users. And depends on has_device_tree > >> or ACPI to select DEVICE_TREE_NUMA or ACPI_NUMA. > >> > >> If we add HAS_DEVICE_TREE || ACPI as dependencies for ARM_NUMA, > >> does it become a loop dependency? > >> > >> > https://lists.xenproject.org/archives/html/xen-devel/2021-08/msg00888.html > > > > OK, I am fine with that. I was just trying to catch the case where a > > user selects "ARM_NUMA" but actually neither ACPI nor HAS_DEVICE_TREE > > are selected so nothing happens. I was trying to make it clear that > > ARM_NUMA depends on having at least one between HAS_DEVICE_TREE or ACPI > > because otherwise it is not going to work. > > > > That said, I don't think this is important because HAS_DEVICE_TREE > > cannot be unselected. So if we cannot find a way to express the > > dependency, I think it is fine to keep the patch as is. > > So how about doing things the other way around: ARM_NUMA has no prompt > and defaults to ACPI_NUMA || DT_NUMA, and DT_NUMA gains a prompt instead > (and, for Arm at least, ACPI_NUMA as well; this might even be worthwhile > to have on x86 down the road). >
As I wrote before, I don't think the user should say "I want to enable NUMA with Device-Tree or ACPI". Instead, they say whether they want to use NUMA and let Xen decide to enable the DT/ACPI support. In other word, the prompt should stay on ARM_NUMA. Cheers, > Jan > >
