Subject: Re: [PATCH 05/17] arch, mm: pull out allocation of NODE_DATA to generic code

From: Mike Rapoport <[email-masked]>
Date: Sat, 20 Jul 2024 13:24:06 +0300

On Wed, Jul 17, 2024 at 04:42:48PM +0200, David Hildenbrand wrote:
> On 16.07.24 13:13, Mike Rapoport 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.
> > 
> > Signed-off-by: Mike Rapoport (Microsoft) <[email-masked]>
> > ---
> 
> [...]
> 
> > diff --git a/arch/mips/loongson64/numa.c b/arch/mips/loongson64/numa.c
> > index 9208eaadf690..909f6cec3a26 100644
> > --- a/arch/mips/loongson64/numa.c
> > +++ b/arch/mips/loongson64/numa.c
> > @@ -81,12 +81,8 @@ static void __init init_topology_matrix(void)
> >   static void __init node_mem_init(unsigned int node)
> >   {
> > -	struct pglist_data *nd;
> >   	unsigned long node_addrspace_offset;
> >   	unsigned long start_pfn, end_pfn;
> > -	unsigned long nd_pa;
> > -	int tnid;
> > -	const size_t nd_size = roundup(sizeof(pg_data_t), SMP_CACHE_BYTES);
> 
> One interesting change is that we now always round up to full pages on
> architectures where we previously rounded up to SMP_CACHE_BYTES.

I did some git archaeology and it seems that round up to full pages on x86
backdates to bootmem era when allocation granularity was PAGE_SIZE anyway.
I'm going to change that to SMP_CACHE_BYTES in v2.
 
> I assume we don't really expect a significant growth in memory consumption
> that we care about, especially because most systems with many nodes also
> have  quite some memory around.

-- 
Sincerely yours,
Mike.