Re: [RFC PATCH 01/12] khugepaged: Rename hpage_collapse_scan_pmd() -> ptes()

Ryan Roberts
2024-12-17T06:43:44Z

On 17/12/2024 04:18, Matthew Wilcox wrote:
> On Mon, Dec 16, 2024 at 10:20:54PM +0530, Dev Jain wrote:
>> -static int hpage_collapse_scan_pmd(struct mm_struct *mm,
>> +static int hpage_collapse_scan_ptes(struct mm_struct *mm,
>
> i don't think this is necessary at all. you're scanning a pmd.
> you might not be scanning in order to collapse to a pmd, but pmd
> is the level you're scanning at.
>

Sorry Matthew, I don't really understand this statement. Prior to the change we
were scanning all PTE entries in a PTE table with the aim of collapsing to a PMD
entry. After the change we are scanning some PTE entries in a PTE table with the
aim of collapsing to either to a multi-PTE-mapped folio or a single-PMD-mapped
folio.

So personally I think "scan_pmd" was a misnomer even before the change - we are
scanning the ptes.