On 6/10/26 6:44 AM, Lance Yang wrote:
>
> On Wed, Jun 10, 2026 at 06:29:12PM +0800, Baolin Wang wrote:
> [...]
>> @@ -1512,8 +1517,12 @@ static enum scan_result mthp_collapse(struct
>> mm_struct *mm,
>> enum scan_result ret;
>>
>> collapse_address = address + offset * PAGE_SIZE;
>> - ret = collapse_huge_page(mm, collapse_address,
>> referenced,
>> - unmapped, cc, order);
>> + if (file)
>> + ret = collapse_file(mm, collapse_address, file,
>> + start + offset, cc, order);
>> + else
>> + ret = collapse_huge_page(mm, collapse_address,
>> + referenced, unmapped, cc,
>> order);
>>
>> switch (ret) {
>> /* Cases where we continue to next collapse candidate */
>> @@ -1521,6 +1530,7 @@ static enum scan_result mthp_collapse(struct mm_struct
>> *mm,
>> collapsed += nr_ptes;
>> fallthrough;
>> case SCAN_PTE_MAPPED_HUGEPAGE:
>
> Looks like SCAN_PTE_MAPPED_HUGEPAGE from collapse_file() get lost for
> the PMD-order case.
This is kinda my fault... I reused the enum PTE_MAPPED_HUGEPAGE (which was only
really used in file collapse) when reporting that a collapse attempts is smaller
or equal to the current order of the folio.
if (!is_pmd_order(order) && folio_order(folio) >= order) {
I will change that in my follow up to use its own (or a different enum).
>
> Previously, collapse_file() returned it straight back to
> collapse_single_pmd(), so we would run try_collapse_pte_mapped_thp().
>
> Now it hits mthp_collapse() fitst, and that case just goes to
> next_offset ...
>
>> + case SCAN_PAGE_COMPOUND:
>> goto next_offset;
>> /* Cases where lower orders might still succeed */
>> case SCAN_ALLOC_HUGE_PAGE_FAIL:
> [...]
>
> Cheers, Lance
>
