On Fri, Jun 05, 2026 at 10:14:17AM -0600, Nico Pache wrote: > 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]>
LGTM, so: Reviewed-by: Lorenzo Stoakes <[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 >
