[RFC PATCH 3/6] mm/mremap: Use pmd/pud_poplulate to update page table entries

[Aneesh Kumar K.V]

On 2/2/21 4:17 PM, Peter Zijlstra wrote:
> On Tue, Feb 02, 2021 at 02:41:13PM +0530, Aneesh Kumar K.V wrote:
>> pmd/pud_populate is the right interface to be used to set the respective
>> page table entries. Some architectures do assume that set_pmd/pud_at
>> can only be used to set a hugepage PTE. Since we are not setting up a hugepage
>> PTE here, use the pmd/pud_populate interface.
> 
> Since you did the audit, it might be nice to record which architectures
> that are. Also, how much work to fix them?
> 

I didn't audit them completely primarily because I don't follow the page 
table format of other archs. But I guess arm64, s390 appears to make 
that assumption.

Moreover set_pmd_at was added as part of THP patch series.

BTW why should we fix those architectures ? isn't pmd_populate the right 
interface for updating pmd entries other than hugepage pte ?

-aneesh