Hi Julien, > -----Original Message----- > From: Julien Grall <jul...@xen.org> > Sent: 2021年8月20日 19:29 > To: Wei Chen <wei.c...@arm.com>; xen-devel@lists.xenproject.org; > sstabell...@kernel.org > Cc: Bertrand Marquis <bertrand.marq...@arm.com> > Subject: Re: [XEN RFC PATCH 17/40] xen/arm: Introduce DEVICE_TREE_NUMA > Kconfig for arm64 > > > > On 20/08/2021 11:49, Wei Chen wrote: > > Hi Julien, > > Hi Wei, > > > > >> -----Original Message----- > >> From: Julien Grall <jul...@xen.org> > >> Sent: 2021年8月20日 16:41 > >> 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 17/40] xen/arm: Introduce DEVICE_TREE_NUMA > >> Kconfig for arm64 > >> > >> On 20/08/2021 03:30, Wei Chen wrote: > >>> Hi Julien, > >> > >> Hi Wei, > >> > >>>> -----Original Message----- > >>>> From: Julien Grall <jul...@xen.org> > >>>> Sent: 2021年8月19日 21:38 > >>>> 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 17/40] xen/arm: Introduce > DEVICE_TREE_NUMA > >>>> Kconfig for arm64 > >>>> > >>>> Hi, > >>>> > >>>> On 11/08/2021 11:24, Wei Chen wrote: > >>>>> We need a Kconfig option to distinguish with ACPI based > >>>>> NUMA. So we introduce the new Kconfig option: > >>>>> DEVICE_TREE_NUMA in this patch for Arm64. > >>>>> > >>>>> Signed-off-by: Wei Chen <wei.c...@arm.com> > >>>>> --- > >>>>> xen/arch/arm/Kconfig | 10 ++++++++++ > >>>>> 1 file changed, 10 insertions(+) > >>>>> > >>>>> diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig > >>>>> index ecfa6822e4..678cc98ea3 100644 > >>>>> --- a/xen/arch/arm/Kconfig > >>>>> +++ b/xen/arch/arm/Kconfig > >>>>> @@ -33,6 +33,16 @@ config ACPI > >>>>> Advanced Configuration and Power Interface (ACPI) support > >> for Xen > >>>> is > >>>>> an alternative to device tree on ARM64. > >>>>> > >>>>> +config DEVICE_TREE_NUMA > >>>> > >>>> The name suggests that NUMA should only be enabled for Device-Tree... > >>>> But the description looks generic. > >>>> > >>>> However, I think the user should only have the choice to say whether > >>>> they want NUMA to be enabled or not. We should not give them the > choice > >>>> to enable/disable the parsing for DT/ACPI. > >>>> > >>>> So we should have a generic config that will then select DT (and ACPI > >> in > >>>> the future). > >>>> > >>> > >>> How about we select DT_NUMA default on Arm64. And DT_NUMA select NUMA > >>> like what we have done in patch#6 in x86? And remove the description? > >> I would rather not make NUMA supported by default on Arm64. Instead, we > >> should go throught the same process as other new features and gate it > >> behind UNSUPPORTED until it is mature enough. > >> > > > > Ok. I agree with this. > > > >>> > >>> If we make generic NUMA as a selectable option, and depends on > >>> NUMA to select DT or ACPI NUMA. It seems to be quite different from > >>> the existing logic? > >> > >> I am a bit confused. You added just logic to select NUMA from ACPI, > >> right? So are you talking about a different logic? > >> > > > > No, I didn't want a different one. I thought you wanted it that way. > > Obviously, I mis-understanded your comments. > > > > Can I understand your previous comments like following: > > 1. We should have a generic config that will then select DT and ACPI: > > Because we already have CONFIG_NUMA in common layer. So we need to > > add another one for Arm like CONFIG_ARM_NUMA? > > I think so. > > > And in this option, we can select CONFIG_DEVICE_TREE_NUMA > > automatically if device tree is enabled. If CONFIG_ACPI > > is enabled, we will select CONFIG_ACPI_NUMA too (in the > > future) > > In Xen code, DT_NUMA and ACPI_NUMA code can co-exist, Xen > > Distributions should not have to build a different Xen for DT and ACPI. > So it is more they *must* co-exist. > > > will check the system ACPI support status to decide to use > > DT_NUMA or ACPI_NUMA? > > Yes. A user should only have to say "I want to use NUMA". This is Xen to > figure out whether we need to compile the support for DT and/or ACPI. > > Once we have support for APCI, it doesn't make a lot of sense for the > users to say "I want to compile with DT and ACPI but I only want NUMA > when using DT". >
I am glad we are now in the same page. Ok, I will change the Kconfig like this in next version. > Cheers, > > -- > Julien Grall