[PATCH v13 mm-new 05/16] khugepaged: introduce is_mthp_order helper

Nico Pache
2025-12-01T17:48:29Z

In order to add mTHP support, we will often be checking if a given order
is a mTHP or PMD order. Lets create a simple helper function to keep the
code clean and readable.

Suggested-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Nico Pache <npache@redhat.com>
---
mm/khugepaged.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 8599c7fa112e..9c041141b2e3 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -338,6 +338,11 @@ static bool pte_none_or_zero(pte_t pte)
return pte_present(pte) && is_zero_pfn(pte_pfn(pte));
}

+static bool is_mthp_order(unsigned int order)
+{
+ return order != HPAGE_PMD_ORDER;
+}
+
int hugepage_madvise(struct vm_area_struct *vma,
vm_flags_t *vm_flags, int advice)
{
@@ -1071,13 +1076,13 @@ static int alloc_charge_folio(struct folio **foliop, struct mm_struct *mm,
folio = __folio_alloc(gfp, order, node, &cc->alloc_nmask);
if (!folio) {
*foliop = NULL;
- if (order == HPAGE_PMD_ORDER)
+ if (!is_mthp_order(order))
count_vm_event(THP_COLLAPSE_ALLOC_FAILED);
count_mthp_stat(order, MTHP_STAT_COLLAPSE_ALLOC_FAILED);
return SCAN_ALLOC_HUGE_PAGE_FAIL;
}

- if (order == HPAGE_PMD_ORDER)
+ if (!is_mthp_order(order))
count_vm_event(THP_COLLAPSE_ALLOC);
count_mthp_stat(order, MTHP_STAT_COLLAPSE_ALLOC);

--
2.51.1