Re: [PATCH 10/12] mm: Remove devmap related functions and page table bits

[Jason Gunthorpe <jgg@ziepe.ca>]

On Thu, May 29, 2025 at 04:32:11PM +1000, Alistair Popple wrote:
> Now that DAX and all other reference counts to ZONE_DEVICE pages are
> managed normally there is no need for the special devmap PTE/PMD/PUD
> page table bits. So drop all references to these, freeing up a
> software defined page table bit on architectures supporting it.
> 
> Signed-off-by: Alistair Popple <apopple@nvidia.com>
> Acked-by: Will Deacon <will@kernel.org> # arm64
> Suggested-by: Chunyan Zhang <zhang.lyra@gmail.com>
> Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
> ---
>  Documentation/mm/arch_pgtable_helpers.rst     |  6 +--
>  arch/arm64/Kconfig                            |  1 +-
>  arch/arm64/include/asm/pgtable-prot.h         |  1 +-
>  arch/arm64/include/asm/pgtable.h              | 24 +--------
>  arch/loongarch/Kconfig                        |  1 +-
>  arch/loongarch/include/asm/pgtable-bits.h     |  6 +--
>  arch/loongarch/include/asm/pgtable.h          | 19 +------
>  arch/powerpc/Kconfig                          |  1 +-
>  arch/powerpc/include/asm/book3s/64/hash-4k.h  |  6 +--
>  arch/powerpc/include/asm/book3s/64/hash-64k.h |  7 +--
>  arch/powerpc/include/asm/book3s/64/pgtable.h  | 53 +------------------
>  arch/powerpc/include/asm/book3s/64/radix.h    | 14 +-----
>  arch/riscv/Kconfig                            |  1 +-
>  arch/riscv/include/asm/pgtable-64.h           | 20 +-------
>  arch/riscv/include/asm/pgtable-bits.h         |  1 +-
>  arch/riscv/include/asm/pgtable.h              | 17 +------
>  arch/x86/Kconfig                              |  1 +-
>  arch/x86/include/asm/pgtable.h                | 51 +-----------------
>  arch/x86/include/asm/pgtable_types.h          |  5 +--
>  include/linux/mm.h                            |  7 +--
>  include/linux/pgtable.h                       | 19 +------
>  mm/Kconfig                                    |  4 +-
>  mm/debug_vm_pgtable.c                         | 59 +--------------------
>  mm/hmm.c                                      |  3 +-
>  mm/madvise.c                                  |  8 +--
>  25 files changed, 17 insertions(+), 318 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason