linux-kernel - [PATCH v13 mm-new 05/16] khugepaged: introduce is_mthp

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Message-ID: <20251201174627.23295-6-npache@redhat.com>
Date: Mon,  1 Dec 2025 10:46:16 -0700
From: Nico Pache <npache@...hat.com>
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Subject: [PATCH v13 mm-new 05/16] khugepaged: introduce is_mthp_order helper

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@...cle.com>
Signed-off-by: Nico Pache <npache@...hat.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