Re: [PATCH 01/26] mm: Do page fault accounting in handle_mm_fault

[John Hubbard]

On 2020-06-26 15:31, Peter Xu wrote:
> This is a preparation patch to move page fault accountings into the general
> code in handle_mm_fault().  This includes both the per task flt_maj/flt_min
> counters, and the major/minor page fault perf events.  To do this, the pt_regs
> pointer is passed into handle_mm_fault().
>
> PERF_COUNT_SW_PAGE_FAULTS should still be kept in per-arch page fault handlers.
>
> So far, all the pt_regs pointer that passed into handle_mm_fault() is NULL,
> which means this patch should have no intented functional change.
>
> Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
> ---
>   arch/alpha/mm/fault.c         |  2 +-
>   arch/arc/mm/fault.c           |  2 +-
>   arch/arm/mm/fault.c           |  2 +-
>   arch/arm64/mm/fault.c         |  2 +-
>   arch/csky/mm/fault.c          |  3 +-
>   arch/hexagon/mm/vm_fault.c    |  2 +-
>   arch/ia64/mm/fault.c          |  2 +-
>   arch/m68k/mm/fault.c          |  2 +-
>   arch/microblaze/mm/fault.c    |  2 +-
>   arch/mips/mm/fault.c          |  2 +-
>   arch/nds32/mm/fault.c         |  2 +-
>   arch/nios2/mm/fault.c         |  2 +-
>   arch/openrisc/mm/fault.c      |  2 +-
>   arch/parisc/mm/fault.c        |  2 +-
>   arch/powerpc/mm/copro_fault.c |  2 +-
>   arch/powerpc/mm/fault.c       |  2 +-
>   arch/riscv/mm/fault.c         |  2 +-
>   arch/s390/mm/fault.c          |  2 +-
>   arch/sh/mm/fault.c            |  2 +-
>   arch/sparc/mm/fault_32.c      |  4 +--
>   arch/sparc/mm/fault_64.c      |  2 +-
>   arch/um/kernel/trap.c         |  2 +-
>   arch/unicore32/mm/fault.c     |  2 +-
>   arch/x86/mm/fault.c           |  2 +-
>   arch/xtensa/mm/fault.c        |  2 +-
>   drivers/iommu/amd_iommu_v2.c  |  2 +-

The above file is renamed, as of a couple weeks ago, via
commit ad8694bac410 ("iommu/amd: Move AMD IOMMU driver into
subdirectory").

Also there are a number of changes to mm/gup.c (not a concern for this
patch, but it is for the overall series). So I'm hoping you're going to
post a version that is rebased against 5.8-rc*.

thanks,
--
John Hubbard
NVIDIA