[PATCH mm-unstable v18 10/14] mm/khugepaged: introduce collapse_allowable_orders helper function
From: Nico Pache <hidden>
Date: 2026-05-22 15:03:12
Also in:
linux-doc, linux-mm, lkml
Subsystem:
memory management, memory management - thp (transparent huge page), the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
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 <baolin.wang@linux.alibaba.com> Signed-off-by: Nico Pache <redacted> --- 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);
--
2.54.0