Re: [PATCH v2 1/3] arm64/numa: export memory_add_physaddr_to_nid as EXPORT_SYMBOL_GPL

Mike Rapoport
2020-07-08T06:22:36Z

On Tue, Jul 07, 2020 at 09:27:43PM -0700, Dan Williams wrote:
> On Tue, Jul 7, 2020 at 9:08 PM Justin He <Justin.He@arm.com> wrote:
> [..]
> > > Especially for architectures that use memblock info for numa info
> > > (which seems to be everyone except x86) why not implement a generic
> > > memory_add_physaddr_to_nid() that does:
> > >
> > > int memory_add_physaddr_to_nid(u64 addr)
> > > {
> > > unsigned long start_pfn, end_pfn, pfn = PHYS_PFN(addr);
> > > int nid;
> > >
> > > for_each_online_node(nid) {
> > > get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
> > > if (pfn >= start_pfn && pfn <= end_pfn)
> > > return nid;
> > > }
> > > return NUMA_NO_NODE;
> > > }
> >
> > Thanks for your suggestion,
> > Could I wrap the codes and let memory_add_physaddr_to_nid simply invoke
> > phys_to_target_node()?
>
> I think it needs to be the reverse. phys_to_target_node() should call
> memory_add_physaddr_to_nid() by default, but fall back to searching
> reserved memory address ranges in memblock. See phys_to_target_node()
> in arch/x86/mm/numa.c. That one uses numa_meminfo instead of memblock,
> but the principle is the same i.e. that a target node may not be
> represented in memblock.memory, but memblock.reserved. I'm working on
> a patch to provide a function similar to get_pfn_range_for_nid() that
> operates on reserved memory.

Do we really need yet another memblock iterator?
I think only x86 has memory that is not in memblock.memory but only in
memblock.reserved.

--
Sincerely yours,
Mike.