On 27.09.2021 10:45, Julien Grall wrote: > 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.
Okay. In which case I'm confused by Stefano's question. Jan
