On 5/22/26 17:00, 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.
It would have been good to describe here that, for now, it only ever returns PMDs, and that it will be extended next. Logically, this patch belongs to #12, not #11 ... so seeing it before #11 was a bit ... and there, it is clear that we don't even want to know the orders? So can we just call this function "collapse_possible" and make it return a boolean? > > Reviewed-by: Baolin Wang <[email protected]> > Signed-off-by: Nico Pache <[email protected]> > --- > mm/khugepaged.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 4534025bc81d..64ceebc9d8a7 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -552,12 +552,21 @@ void __khugepaged_enter(struct mm_struct *mm) > wake_up_interruptible(&khugepaged_wait); > } > > +/* 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, enum tva_type tva_flags) > +{ > + unsigned long orders = BIT(HPAGE_PMD_ORDER); > + > + return thp_vma_allowable_orders(vma, vm_flags, tva_flags, orders); > +} > + > 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_allowable_orders(vma, vm_flags, TVA_KHUGEPAGED)) > __khugepaged_enter(vma->vm_mm); > } > } > @@ -2680,7 +2689,7 @@ 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_allowable_orders(vma, vma->vm_flags, > TVA_KHUGEPAGED)) { > cc->progress++; > continue; > } > @@ -2989,7 +2998,7 @@ 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, TVA_FORCED_COLLAPSE)) > return -EINVAL; > > cc = kmalloc_obj(*cc); Having a simple static bool collapse_possible(...) { return collapse_allowable_orders(...) } Would make the above slightly more readable. Acked-by: David Hildenbrand (Arm) <[email protected]> -- Cheers, David
