Re: [RFC PATCH v4 09/27] x86/mm: Change _PAGE_DIRTY to _PAGE_DIRTY_HW

On 10/03/2018 06:38 AM, Matthew Wilcox wrote:

On Fri, Sep 21, 2018 at 08:03:33AM -0700, Yu-cheng Yu wrote:

quoted

We are going to create _PAGE_DIRTY_SW for non-hardware, memory
management purposes.  Rename _PAGE_DIRTY to _PAGE_DIRTY_HW and
_PAGE_BIT_DIRTY to _PAGE_BIT_DIRTY_HW to make these PTE dirty
bits more clear.  There are no functional changes in this
patch.

I would like there to be some documentation in this patchset which
explains the difference between PAGE_SOFT_DIRTY and PAGE_DIRTY_SW.

Also, is it really necessary to rename PAGE_DIRTY?  It feels like a
lot of churn.

This is a lot of churn?  Are we looking a the same patch? :)

 arch/x86/include/asm/pgtable.h       |  6 +++---
 arch/x86/include/asm/pgtable_types.h | 17 +++++++++--------
 arch/x86/kernel/relocate_kernel_64.S |  2 +-
 arch/x86/kvm/vmx.c                   |  2 +-
 4 files changed, 14 insertions(+), 13 deletions(-)

But, yeah, I think we need to.  While it will take a little adjustment
in the brains of us old-timers and a bit of pain when switching from old
kernels to new, this makes it a lot more clear what is going on.