Add collapse_possible_orders() to generalize THP order eligibility. The function determines which THP orders are permitted based on collapse context (khugepaged vs madv_collapse). We also add collapse_possible() as a thin wrapper around collapse_possible_orders() that returns a bool rather than the whole bitmap.
This consolidates collapse configuration logic and provides a clean interface for future mTHP collapse support where the orders may be different. Acked-by: David Hildenbrand (Arm) <[email protected]> Reviewed-by: Baolin Wang <[email protected]> Signed-off-by: Nico Pache <[email protected]> --- mm/khugepaged.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 26c343a6fa3d..ec886a031952 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -554,12 +554,30 @@ void __khugepaged_enter(struct mm_struct *mm) wake_up_interruptible(&khugepaged_wait); } +/* + * Check what orders are possible based on the vma and collapse type. + * This is used to determine if mTHP collapse is a viable option. + */ +static unsigned long collapse_possible_orders(struct vm_area_struct *vma, + vm_flags_t vm_flags, enum tva_type tva_flags) +{ + const unsigned long orders = BIT(HPAGE_PMD_ORDER); + + return thp_vma_allowable_orders(vma, vm_flags, tva_flags, orders); +} + +static bool collapse_possible(struct vm_area_struct *vma, + vm_flags_t vm_flags, enum tva_type tva_flags) +{ + return collapse_possible_orders(vma, vm_flags, tva_flags); +} + void khugepaged_enter_vma(struct vm_area_struct *vma, vm_flags_t vm_flags) { if (!mm_flags_test(MMF_VM_HUGEPAGE, vma->vm_mm) && hugepage_pmd_enabled()) { - if (thp_vma_allowable_order(vma, vm_flags, TVA_KHUGEPAGED, PMD_ORDER)) + if (collapse_possible(vma, vm_flags, TVA_KHUGEPAGED)) __khugepaged_enter(vma->vm_mm); } } @@ -2700,7 +2718,7 @@ static void collapse_scan_mm_slot(unsigned int progress_max, cc->progress++; break; } - if (!thp_vma_allowable_order(vma, vma->vm_flags, TVA_KHUGEPAGED, PMD_ORDER)) { + if (!collapse_possible(vma, vma->vm_flags, TVA_KHUGEPAGED)) { cc->progress++; continue; } @@ -3010,7 +3028,7 @@ int madvise_collapse(struct vm_area_struct *vma, unsigned long start, BUG_ON(vma->vm_start > start); BUG_ON(vma->vm_end < end); - if (!thp_vma_allowable_order(vma, vma->vm_flags, TVA_FORCED_COLLAPSE, PMD_ORDER)) + if (!collapse_possible(vma, vma->vm_flags, TVA_FORCED_COLLAPSE)) return -EINVAL; cc = kmalloc_obj(*cc); -- 2.54.0
