[PATCH v4 04/13] mm/vmemmap: Allow architectures to override how vmemmap optimization works

[Christophe Leroy]

Le 10/07/2023 à 18:08, Aneesh Kumar K.V a écrit :
> Architectures like powerpc will like to use different page table allocators
> and mapping mechanisms to implement vmemmap optimization. Similar to
> vmemmap_populate allow architectures to implement
> vmemap_populate_compound_pages
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>
> ---
>   mm/sparse-vmemmap.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
> index a044a130405b..541b3f69a481 100644
> --- a/mm/sparse-vmemmap.c
> +++ b/mm/sparse-vmemmap.c
> @@ -141,6 +141,7 @@ void __meminit vmemmap_verify(pte_t *pte, int node,
>   			start, end - 1);
>   }
>   
> +#ifndef vmemmap_populate_compound_pages
>   pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,
>   				       struct vmem_altmap *altmap,
>   				       struct page *reuse)

Should vmemmap_pte_populate() be static ?

It looks odd to exclude a non-static function based on a non related macro.

There are several such function in the block being excluded here. Can 
you explain why it is correct to do that ?

> @@ -446,6 +447,8 @@ static int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn,
>   	return 0;
>   }
>   
> +#endif
> +
>   struct page * __meminit __populate_section_memmap(unsigned long pfn,
>   		unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
>   		struct dev_pagemap *pgmap)