[RFC PATCH 03/11] mm: khugepaged: add an order check for THP statistics

[Baolin Wang]

In order to support file/shmem mTHP collapse in the following patches, add
an PMD-sized THP order check to avoid PMD-sized THP statistics errors.

No functional changes.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
 mm/khugepaged.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index e64ed86d28ca..195c26699118 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -2411,10 +2411,12 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr,
 		xas_lock_irq(&xas);
 	}
 
-	if (is_shmem)
-		__lruvec_stat_mod_folio(new_folio, NR_SHMEM_THPS, HPAGE_PMD_NR);
-	else
-		__lruvec_stat_mod_folio(new_folio, NR_FILE_THPS, HPAGE_PMD_NR);
+	if (order == HPAGE_PMD_ORDER) {
+		if (is_shmem)
+			__lruvec_stat_mod_folio(new_folio, NR_SHMEM_THPS, HPAGE_PMD_NR);
+		else
+			__lruvec_stat_mod_folio(new_folio, NR_FILE_THPS, HPAGE_PMD_NR);
+	}
 
 	if (nr_none) {
 		__lruvec_stat_mod_folio(new_folio, NR_FILE_PAGES, nr_none);
-- 
2.43.5