Subject: Re: [PATCH v3 09/26] arch, mm: pull out allocation of NODE_DATA to generic code

From: Mike Rapoport <[email-masked]>
Date: Mon, 5 Aug 2024 20:15:22 +0300

On Fri, Aug 02, 2024 at 10:55:27AM +0100, Jonathan Cameron wrote:
> On Thu,  1 Aug 2024 09:08:09 +0300
> Mike Rapoport <[email-masked]> wrote:
> 
> > From: "Mike Rapoport (Microsoft)" <[email-masked]>
> > 
> > Architectures that support NUMA duplicate the code that allocates
> > NODE_DATA on the node-local memory with slight variations in reporting
> > of the addresses where the memory was allocated.
> > 
> > Use x86 version as the basis for the generic alloc_node_data() function
> > and call this function in architecture specific numa initialization.
> > 
> > Round up node data size to SMP_CACHE_BYTES rather than to PAGE_SIZE like
> > x86 used to do since the bootmem era when allocation granularity was
> > PAGE_SIZE anyway.
> > 
> > Signed-off-by: Mike Rapoport (Microsoft) <[email-masked]>
> > Acked-by: David Hildenbrand <[email-masked]>
> > Reviewed-by: Jonathan Cameron <[email-masked]>
> > Tested-by: Zi Yan <[email-masked]> # for x86_64 and arm64
> 
> One comment unrelated to this patch set as such, just made
> more obvious by it.
> 
> > diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
> > index 0744a9a2944b..3c1da08304d0 100644
> > --- a/arch/powerpc/mm/numa.c
> > +++ b/arch/powerpc/mm/numa.c
> > @@ -1093,27 +1093,9 @@ void __init dump_numa_cpu_topology(void)
> >  static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
> >  {
> >  	u64 spanned_pages = end_pfn - start_pfn;
> 
> Trivial, but might as well squash this local variable into the
> single place it's used.

> > -	const size_t nd_size = roundup(sizeof(pg_data_t), SMP_CACHE_BYTES);

...

> > +
> > +	alloc_node_data(nid);
> > +
> >  	NODE_DATA(nid)->node_id = nid;
> >  	NODE_DATA(nid)->node_start_pfn = start_pfn;
> >  	NODE_DATA(nid)->node_spanned_pages = spanned_pages;

These are actually overridden later in free_area_init(), it would make
sense to audit all arch-specific node setup functions and clean them up a
bit.

-- 
Sincerely yours,
Mike.