Re: [PATCH v8 02/10] powerpc/8xx: add pte_set_huge()

[Wen Jiang]

On Fri, 18 Sept 2026 at 07:28, Barry Song <baohua@xxxxxxxxxx> wrote:
>
> On Thu, Sep 17, 2026 at 1:30 PM Wen Jiang <jiangwenxiaomi@xxxxxxxxx> wrote:
> >
> > From: Wen Jiang <jiangwen6@xxxxxxxxxx>
> >
> > vmap installs PTE-level block mappings (SZ_16K/SZ_512K on powerpc/8xx)
> > by reusing set_huge_pte_at(), a HugeTLB helper gated by
> > CONFIG_HUGETLB_PAGE. This makes the feature silently unavailable on
> > CONFIG_HUGETLB_PAGE=n kernels and couples mm/vmalloc.c to HugeTLB
> > internals it does not otherwise need.
> >
> > Add pte_set_huge() to powerpc/8xx, next to the existing
> > pmd_clear_huge()/pud_clear_huge() in mm/nohash/8xx.c. It builds the huge
> > PTE and writes it into the backing cells directly, without going through
> > set_huge_pte_at(), so it does not depend on CONFIG_HUGETLB_PAGE.
> >
> > No pte_clear_huge() is needed: 8xx does not implement
> > arch_vmap_pte_range_unmap_size(), so the vmap unmap path never takes the
> > block-mapping branch.
>
> I assume you mean the block-unmapping (or PTE-clearing) branch.
> Please make this clear in the changelog.
>

Sure. Will fix it.

Thanks,
Wen

> >
> > In practice PPC_8xx selects HUGETLBFS unconditionally, so
> > CONFIG_HUGETLB_PAGE=n does not occur there today; this is a decoupling
> > cleanup rather than a new configuration.
> >
> > There is no caller yet: mm/vmalloc.c is converted later in this series,
> > once the generic fallbacks are in place.
> >
> > Signed-off-by: Wen Jiang <jiangwen6@xxxxxxxxxx>
> > ---
>
> BTW, this patch applies cleanly to the mm-new branch.
>
> Best Regards
> Barry