Re: [PATCH 0/3] Convert x86/mm/pat to ptdescs

From: Mike Rapoport

Date: Wed Jan 28 2026 - 06:53:57 EST


Hi Vishal,

On Mon, Jan 26, 2026 at 04:51:37PM -0800, Vishal Moola (Oracle) wrote:
> x86/mm/pat should be using ptdescs. One line has already been
> converted to pagetable_free(), while the allocation sites use
> get_free_pages(). This causes issues separately allocating ptdescs
> from struct page.
>
> These patches convert the allocation/free sites to use ptdescs. In
> the short term, this helps enable Matthew's work to allocate frozen
> pagetables. And in the long term, this will help us cleanly split
> ptdesc allocations from struct page.
>
> ------
>
> Based on current mm-new.
>
> Vishal Moola (Oracle) (3):
> x86/mm/pat: Convert pte code to use ptdescs
> x86/mm/pat: Convert pmd code to use ptdescs

There are still get_zeroed_page() calls in populate_pgd(). I think they
also should be converted to pagetable_alloc().

Other than that LGTM.

> x86/mm/pat: Convert split_large_page() to use ptdescs
>
> arch/x86/mm/pat/set_memory.c | 37 +++++++++++++++++++-----------------
> 1 file changed, 20 insertions(+), 17 deletions(-)
>
> --
> 2.52.0
>

--
Sincerely yours,
Mike.