Re: [PATCH v5 2/5] mm/sparse-vmemmap: refactor core of vmemmap_populate_basepages() to helper

[Muchun Song <songmuchun@bytedance.com>]

On Fri, Feb 11, 2022 at 3:34 AM Joao Martins <joao.m.martins@oracle.com> wrote:
>
> In preparation for describing a memmap with compound pages, move the
> actual pte population logic into a separate function
> vmemmap_populate_address() and have vmemmap_populate_basepages() walk
> through all base pages it needs to populate.
>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
>  mm/sparse-vmemmap.c | 51 ++++++++++++++++++++++++++++-----------------
>  1 file changed, 32 insertions(+), 19 deletions(-)
>
> diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
> index c506f77cff23..e7be2ef4454b 100644
> --- a/mm/sparse-vmemmap.c
> +++ b/mm/sparse-vmemmap.c
> @@ -608,33 +608,46 @@ pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
>         return pgd;
>  }
>
> -int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end,
> -                                        int node, struct vmem_altmap *altmap)
> +static int __meminit vmemmap_populate_address(unsigned long addr, int node,
> +                                             struct vmem_altmap *altmap)

How about making it return a "pte_t *" instead of int. If it returns NULL
meaning NOMEM. I'll explain the reason in the next patch.

Thanks.