RFC Add PUD and kernel PTE level pagetable account

Hi,

Now we will miss to account the PUD level pagetable and kernel PTE level pagetable, as well as missing to set the PG_table flags for these pagetable pages, which will get an inaccurate pagetable accounting, and miss PageTable() validation in some cases. So this patch set introduces 2 new helpers to help to account PUD and kernel PTE pagetable pages.

Note there are still some architectures specific pagetable allocation that need to account the pagetable pages, which need more investigation and cleanup in future. Now I only send patches to mm mailist, and if no objections from mm people, then I will send to the related arch's maillist to get more review. Thanks.

Changes from RFC v2:
- Convert to use mod_lruvec_page_state() for non-order-0 case.
- Rename the helpers.
- Update some commit messages.
- Remove unnecessary __GFP_HIGHMEM clear.

Note: I still keep using alloc_pages() to allocate page in this version, which follows pmd_alloc_one() and saves unnecessary conversion pointed out by Matthew.

Changes from RFC v1:
- Update some commit message.
- Add missing pgtable_clear_and_dec() on X86 arch.
- Use __free_page() to free pagetable which can avoid duplicated virt_to_page().

Baolin Wang (3):
mm: Factor out the pagetable pages account into new helper function
mm: Add PUD level pagetable account
mm: Add kernel PTE level pagetable pages account

 arch/arm64/include/asm/tlb.h         |  5 ++++-
 arch/csky/include/asm/pgalloc.h      |  2 +-
 arch/loongarch/include/asm/pgalloc.h | 11 ++++++++---
 arch/microblaze/mm/pgtable.c         |  2 +-
 arch/mips/include/asm/pgalloc.h      | 11 ++++++++---
 arch/openrisc/mm/ioremap.c           |  2 +-
 arch/s390/include/asm/tlb.h          |  1 +
 arch/x86/mm/pgtable.c                | 10 ++++++++--
 include/asm-generic/pgalloc.h        | 26 ++++++++++++++++++++++----
 include/linux/mm.h                   | 24 ++++++++++++++++--------
 10 files changed, 70 insertions(+), 24 deletions(-)

1.8.3.1