Re: [PATCH v2 15/46] hugetlb: add make_huge_pte_with_shift

[James Houghton]

On Wed, Feb 22, 2023 at 1:15 PM Mina Almasry <almasrymina@xxxxxxxxxx> wrote:
>
> On Fri, Feb 17, 2023 at 4:28 PM James Houghton <jthoughton@xxxxxxxxxx> wrote:
> >
> > This allows us to make huge PTEs at shifts other than the hstate shift,
> > which will be necessary for high-granularity mappings.
> >
> > Acked-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
> > Signed-off-by: James Houghton <jthoughton@xxxxxxxxxx>
> >
>
> Reviewed-by: Mina Almasry <almasrymina@xxxxxxxxxx>

Thank you :)

>
> > diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> > index f74183acc521..ed1d806020de 100644
> > --- a/mm/hugetlb.c
> > +++ b/mm/hugetlb.c
> > @@ -5110,11 +5110,11 @@ const struct vm_operations_struct hugetlb_vm_ops = {
> >         .pagesize = hugetlb_vm_op_pagesize,
> >  };
> >
> > -static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
> > -                               int writable)
> > +static pte_t make_huge_pte_with_shift(struct vm_area_struct *vma,
> > +                                     struct page *page, int writable,
> > +                                     int shift)
>
> Nit: can this be 'unsigned int shift'. Because you're actually passing
> it an unsigned int below and there is an implicit cast there. Yes it
> will never matter, I know...

Yes I think it should be unsigned int. Thanks for the catch.

>
> >  {
> >         pte_t entry;
> > -       unsigned int shift = huge_page_shift(hstate_vma(vma));
> >
> >         if (writable) {
> >                 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_pte(page,
> > @@ -5128,6 +5128,14 @@ static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
> >         return entry;
> >  }
> >
> > +static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
> > +                          int writable)
> > +{
> > +       unsigned int shift = huge_page_shift(hstate_vma(vma));
> > +
> > +       return make_huge_pte_with_shift(vma, page, writable, shift);
> > +}
> > +
> >  static void set_huge_ptep_writable(struct vm_area_struct *vma,
> >                                    unsigned long address, pte_t *ptep)
> >  {
> > --
> > 2.39.2.637.g21b0678d19-goog
> >