Re: [PATCH v15 06/26] x86/mm: Change _PAGE_DIRTY to _PAGE_DIRTY_HW

Yu, Yu-cheng
2020-12-03T15:57:38Z

On 12/3/2020 7:12 AM, Dave Hansen wrote:
> On 12/3/20 1:19 AM, Borislav Petkov wrote:
>> On Tue, Nov 10, 2020 at 08:21:51AM -0800, Yu-cheng Yu wrote:
>>> Before introducing _PAGE_COW for non-hardware memory management purposes in
>>> the next patch, rename _PAGE_DIRTY to _PAGE_DIRTY_HW and _PAGE_BIT_DIRTY to
>>> _PAGE_BIT_DIRTY_HW to make meanings more clear. There are no functional
>>> changes from this patch.
>> There's no guarantee for "next" or "this" patch when a patch gets
>> applied so reword your commit message pls.
>>
>> Also, I fail to understand here what _PAGE_DIRTY_HW makes more clear?
>> The page dirty bit is clear enough to me so why the churn?
>
> Once upon a time in this set, we had:
>
> _PAGE_DIRTY (the old hardware bit)
> and
> _PAGE_DIRTY_SW (the new shadow stack necessitated bit)
>
> In *that* case, it made sense to change the name of the hardware one to
> help differentiate them. But, over time, we changed _PAGE_DIRTY_SW to
> _PAGE_COW.
>
> I think you're right. The renaming is just churn now with the current
> naming.
>

Ok, I will drop this patch.