On Wed, Oct 22, 2025 at 12:37:13PM -0600, Nico Pache wrote: > Add collapse_allowable_orders() to generalize THP order eligibility. The > function determines which THP orders are permitted based on collapse > context (khugepaged vs madv_collapse). > > This consolidates collapse configuration logic and provides a clean > interface for future mTHP collapse support where the orders may be > different. > > Reviewed-by: Baolin Wang <[email protected]> > Signed-off-by: Nico Pache <[email protected]>
With nits below adddressed, LGTM so: Reviewed-by: Lorenzo Stoakes <[email protected]> > --- > mm/khugepaged.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 0dbbe04c31fe..89a105124790 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -489,7 +489,16 @@ static unsigned int collapse_max_ptes_none(unsigned int > order, bool full_scan) > max_ptes_none = min(khugepaged_max_ptes_none, HPAGE_PMD_NR/2 - 1); > > return max_ptes_none >> (HPAGE_PMD_ORDER - order); > +} > + > +/* Check what orders are allowed based on the vma and collapse type */ > +static unsigned long collapse_allowable_orders(struct vm_area_struct *vma, > + vm_flags_t vm_flags, bool is_khugepaged) > +{ > + enum tva_type tva_flags = is_khugepaged ? TVA_KHUGEPAGED : > TVA_FORCED_COLLAPSE; > + unsigned long orders = BIT(HPAGE_PMD_ORDER); Nit, but can const-ify. > > + return thp_vma_allowable_orders(vma, vm_flags, tva_flags, orders); > } > > void khugepaged_enter_vma(struct vm_area_struct *vma, > @@ -497,7 +506,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma, > { > 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_allowable_orders(vma, vm_flags, true)) If we have a 'mystery meat' boolean parameter can we always use the convention of: collapse_allowable_orders(vma, vm_flags, /*is_khugepaged=*/true) Please? Same goes for other invocations obviously. > __khugepaged_enter(vma->vm_mm); > } > } > @@ -2567,7 +2576,7 @@ static unsigned int collapse_scan_mm_slot(unsigned int > pages, int *result, > progress++; > break; > } > - if (!thp_vma_allowable_order(vma, vma->vm_flags, > TVA_KHUGEPAGED, PMD_ORDER)) { > + if (!collapse_allowable_orders(vma, vma->vm_flags, true)) { > skip: > progress++; > continue; > @@ -2873,7 +2882,7 @@ 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_allowable_orders(vma, vma->vm_flags, false)) > return -EINVAL; > > cc = kmalloc(sizeof(*cc), GFP_KERNEL); > -- > 2.51.0 >
