From: Mike Rapoport <rppt@linux.ibm.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Kaly Xin <Kaly.Xin@arm.com>, Jia He <justin.he@arm.com>,
Baoquan He <bhe@redhat.com>, David Hildenbrand <david@redhat.com>,
Catalin Marinas <catalin.marinas@arm.com>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
Chuhong Yuan <hslester96@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Michal Hocko <mhocko@kernel.org>, Linux MM <linux-mm@kvack.org>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Will Deacon <will@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2 1/3] arm64/numa: export memory_add_physaddr_to_nid as EXPORT_SYMBOL_GPL
Date: Wed, 8 Jul 2020 08:27:46 +0300 [thread overview]
Message-ID: <20200708052626.GB386073@linux.ibm.com> (raw)
In-Reply-To: <CAPcyv4iB-vP8U4pH_3jptfODbiNqJZXoTmA6+7EHoddk9jBgEQ@mail.gmail.com>
On Tue, Jul 07, 2020 at 03:05:48PM -0700, Dan Williams wrote:
> On Tue, Jul 7, 2020 at 11:01 AM Mike Rapoport <rppt@linux.ibm.com> wrote:
> >
> > On Tue, Jul 07, 2020 at 02:26:08PM +0200, David Hildenbrand wrote:
> > > On 07.07.20 14:13, Mike Rapoport wrote:
> > > > On Tue, Jul 07, 2020 at 01:54:54PM +0200, Michal Hocko wrote:
> > > >> On Tue 07-07-20 13:59:15, Jia He wrote:
> > > >>> This exports memory_add_physaddr_to_nid() for module driver to use.
> > > >>>
> > > >>> memory_add_physaddr_to_nid() is a fallback option to get the nid in case
> > > >>> NUMA_NO_NID is detected.
> > > >>>
> > > >>> Suggested-by: David Hildenbrand <david@redhat.com>
> > > >>> Signed-off-by: Jia He <justin.he@arm.com>
> > > >>> ---
> > > >>> arch/arm64/mm/numa.c | 5 +++--
> > > >>> 1 file changed, 3 insertions(+), 2 deletions(-)
> > > >>>
> > > >>> diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c
> > > >>> index aafcee3e3f7e..7eeb31740248 100644
> > > >>> --- a/arch/arm64/mm/numa.c
> > > >>> +++ b/arch/arm64/mm/numa.c
> > > >>> @@ -464,10 +464,11 @@ void __init arm64_numa_init(void)
> > > >>>
> > > >>> /*
> > > >>> * We hope that we will be hotplugging memory on nodes we already know about,
> > > >>> - * such that acpi_get_node() succeeds and we never fall back to this...
> > > >>> + * such that acpi_get_node() succeeds. But when SRAT is not present, the node
> > > >>> + * id may be probed as NUMA_NO_NODE by acpi, Here provide a fallback option.
> > > >>> */
> > > >>> int memory_add_physaddr_to_nid(u64 addr)
> > > >>> {
> > > >>> - pr_warn("Unknown node for memory at 0x%llx, assuming node 0\n", addr);
> > > >>> return 0;
> > > >>> }
> > > >>> +EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
> > > >>
> > > >> Does it make sense to export a noop function? Wouldn't make more sense
> > > >> to simply make it static inline somewhere in a header? I haven't checked
> > > >> whether there is an easy way to do that sanely bu this just hit my eyes.
> > > >
> > > > We'll need to either add a CONFIG_ option or arch specific callback to
> > > > make both non-empty (x86, powerpc, ia64) and empty (arm64, sh)
> > > > implementations coexist ...
> > >
> > > Note: I have a similar dummy (return 0) patch for s390x lying around here.
> >
> > Then we'll call it a tie - 3:3 ;-)
>
> So I'd be happy to jump on the train of people wanting to export the
> ARM stub for this (and add a new ARM stub for phys_to_target_node()),
> but Will did have a plausibly better idea that I have been meaning to
> circle back to:
>
> http://lore.kernel.org/r/20200325111039.GA32109@willie-the-truck
>
> ...i.e. iterate over node data to do the lookup. This would seem to
> work generically for multiple archs unless I am missing something?
I think it would work on arm64, power and, most propbably on s390
(David?), but not on x86. x86 does not have reserved memory in pgdat,
it's never memblock_add()'ed (see e820__memblock_setup()).
I've suggested to add E820_*_RESERVED to memblock.memory a while ago
[1], but apparently there are systems that cannot tolerate OS mappings
of the BIOS reserved areas.
[1] https://lore.kernel.org/lkml/20200522142053.GW1059226@linux.ibm.com/
--
Sincerely yours,
Mike.
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-07-08 5:31 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 5:59 [PATCH v2 0/3] Fix and enable pmem as RAM device on arm64 Jia He
2020-07-07 5:59 ` [PATCH v2 1/3] arm64/numa: export memory_add_physaddr_to_nid as EXPORT_SYMBOL_GPL Jia He
2020-07-07 11:35 ` David Hildenbrand
2020-07-07 11:54 ` Michal Hocko
2020-07-07 12:13 ` Mike Rapoport
2020-07-07 12:26 ` David Hildenbrand
2020-07-07 18:00 ` Mike Rapoport
2020-07-07 22:05 ` Dan Williams
2020-07-08 5:27 ` Mike Rapoport [this message]
2020-07-08 7:21 ` David Hildenbrand
2020-07-08 7:38 ` Mike Rapoport
2020-07-08 7:40 ` David Hildenbrand
2020-07-08 7:50 ` Dan Williams
2020-07-08 8:26 ` David Hildenbrand
2020-07-08 8:39 ` Mike Rapoport
2020-07-08 8:45 ` David Hildenbrand
2020-07-08 9:15 ` Mike Rapoport
2020-07-08 9:25 ` David Hildenbrand
2020-07-08 9:45 ` Mike Rapoport
2020-07-08 10:04 ` David Hildenbrand
2020-07-08 15:50 ` Dan Williams
2020-07-08 16:10 ` David Hildenbrand
2020-07-08 16:47 ` Mike Rapoport
2020-07-08 2:20 ` Justin He
2020-07-08 3:56 ` Dan Williams
2020-07-08 4:08 ` Justin He
2020-07-08 4:27 ` Dan Williams
2020-07-08 6:22 ` Mike Rapoport
2020-07-08 6:53 ` Dan Williams
2020-07-08 6:59 ` David Hildenbrand
2020-07-08 7:04 ` Dan Williams
2020-07-08 7:16 ` David Hildenbrand
2020-07-08 7:43 ` Mike Rapoport
2020-07-08 5:32 ` Mike Rapoport
2020-07-08 5:48 ` Dan Williams
2020-07-08 6:19 ` Mike Rapoport
2020-07-08 6:44 ` Dan Williams
2020-07-08 6:56 ` Justin He
2020-07-08 7:00 ` David Hildenbrand
2020-07-07 5:59 ` [RFC PATCH v2 2/3] device-dax: use fallback nid when numa_node is invalid Jia He
2020-07-07 6:08 ` Justin He
2020-07-07 11:34 ` David Hildenbrand
2020-07-08 1:41 ` Justin He
2020-07-07 5:59 ` [PATCH v2 3/3] mm/memory_hotplug: fix unpaired mem_hotplug_begin/done Jia He
2020-07-07 10:06 ` Michal Hocko
2020-07-07 11:31 ` David Hildenbrand
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