Hi Jan, > -----Original Message----- > From: Jan Beulich <jbeul...@suse.com> > Sent: 2022年9月30日 14:03 > To: Wei Chen <wei.c...@arm.com> > Cc: nd <n...@arm.com>; Andrew Cooper <andrew.coop...@citrix.com>; Roger Pau > Monné <roger....@citrix.com>; Wei Liu <w...@xen.org>; George Dunlap > <george.dun...@citrix.com>; Julien Grall <jul...@xen.org>; Stefano > Stabellini <sstabell...@kernel.org>; xen-devel@lists.xenproject.org > Subject: Re: [PATCH v5 5/6] xen/x86: move NUMA scan nodes codes from x86 > to common > > On 30.09.2022 03:40, Wei Chen wrote: > >> -----Original Message----- > >> From: Jan Beulich <jbeul...@suse.com> > >> Sent: 2022年9月29日 20:21 > >> > >> On 29.09.2022 10:21, Wei Chen wrote: > >>> On 2022/9/27 23:48, Jan Beulich wrote: > >>>> On 20.09.2022 11:12, Wei Chen wrote: > >>>>> --- a/xen/drivers/acpi/Kconfig > >>>>> +++ b/xen/drivers/acpi/Kconfig > >>>>> @@ -7,4 +7,5 @@ config ACPI_LEGACY_TABLES_LOOKUP > >>>>> > >>>>> config ACPI_NUMA > >>>>> bool > >>>>> + select HAS_NUMA_NODE_FWID > >>>>> select NUMA > >>>> > >>>> While I might guess that you've chosen the insertion point to have > >>>> things sorted alphabetically, I think here it would be more natural > >>>> to select the wider option first and then also select the more > >>>> narrow one. > >>>> > >>> > >>> Ok, I will adjust the order. > >>> > >>>> One further question though: How is this going to work for Arm64 > >>>> once it wants to support both the form of NUMA you're working to > >>>> enable _and_ ACPI-based NUMA? There better wouldn't be a requirement > >>>> to pick one of the two at build time - it would be nice for support > >>>> of both forms to be able to co-exist in a single binary. > >>> > >>> We are also working in this way. In part#3, we will check ACPI first, > >>> only when ACPI is off, the DT NUMA will be used by Arm. If ACPI is on, > >>> we will skip DT NUMA. > >> > >> Even more so an answer to my question would be nice: You'll then have > >> CONFIG_HAS_NUMA_NODE_FWID=y even on Arm (using PXM as mandated by ACPI > >> when in ACPI mode). But then what's the FWID for DT? I know it was me > >> to suggest this build time distinction, but I'm afraid I wasn't doing > >> much good with that (and I'm sorry). > > > > How about introducing a flag for selected NUMA implementation to > > set it in runtime? > > For example: > > bool numa_has_fw_nodeid; > > > > ACPI NUMA will set this flag to 1, but 0 for DT NUMA. > > That's an option alongside going back to what you had in an earlier > version. Another would be (name subject to improvement) > > const char *__ro_after_init numa_fw_nid_name; > > which for ACPI would be set to "PXM" (eliminating the need to pass > it to certain functions, albeit the fw_nid will continue to need to > be passed anyway). I guess I'm not really certain which of this and > your earlier approach I prefer; the boolean you suggest above looks > less desirable to me, though. >
Ok, I will follow your suggestion. Cheers, Wei Chen > Jan
