Re: [PATCH V3 3/4] mm/sparse-vmemmap: Generalise vmemmap_populate_hugepages()

[Huacai Chen <chenhuacai@kernel.org>]

Hi, Will,

On Mon, Jul 4, 2022 at 5:27 PM Will Deacon <will@kernel.org> wrote:
>
> On Sat, Jul 02, 2022 at 04:00:20PM +0800, Huacai Chen wrote:
> > From: Feiyang Chen <chenfeiyang@loongson.cn>
> >
> > Generalise vmemmap_populate_hugepages() so ARM64 & X86 & LoongArch can
> > share its implementation.
> >
> > Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
> > Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> > ---
> >  arch/arm64/mm/mmu.c      | 53 ++++++-----------------
> >  arch/loongarch/mm/init.c | 63 ++++++++-------------------
> >  arch/x86/mm/init_64.c    | 92 ++++++++++++++--------------------------
> >  include/linux/mm.h       |  6 +++
> >  mm/sparse-vmemmap.c      | 54 +++++++++++++++++++++++
> >  5 files changed, 124 insertions(+), 144 deletions(-)
> >
> > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> > index 626ec32873c6..b080a65c719d 100644
> > --- a/arch/arm64/mm/mmu.c
> > +++ b/arch/arm64/mm/mmu.c
> > @@ -1158,49 +1158,24 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
> >       return vmemmap_populate_basepages(start, end, node, altmap);
> >  }
> >  #else        /* !ARM64_KERNEL_USES_PMD_MAPS */
> > +void __meminit vmemmap_set_pmd(pmd_t *pmd, void *p, int node,
> > +                            unsigned long addr, unsigned long next)
> > +{
> > +     pmd_set_huge(pmd, __pa(p), __pgprot(PROT_SECT_NORMAL));
> > +}
> > +
> > +int __meminit vmemmap_check_pmd(pmd_t *pmd, int node, unsigned long addr,
> > +                             unsigned long next)
> > +{
> > +     vmemmap_verify((pte_t *)pmd, node, addr, next);
> > +     return 1;
> > +}
>
> nit, but please can you use 'pmdp' instead of 'pmd' for the pointers? We're
> pretty consistent elsewhere for arch/arm64 and it makes the READ_ONCE()
> usage easier to follow once functions end up loading the entry.
OK, I will change to pmdp for ARM64, thanks.

Huacai
>
> Thanks,
>
> Will