[RFC PATCH v2 06/11] mm: khugepaged: allow khugepaged to check all shmem mTHP-sized orders

[Baolin Wang]

We are now ready to enable shmem mTHP collapse, allowing
thp_vma_allowable_orders() to check all permissible shmem large orders.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
 mm/khugepaged.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 75b18ec4a6c3..a87918b7e18c 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -578,9 +578,14 @@ static unsigned long collapse_possible_orders(struct vm_area_struct *vma,
 {
 	unsigned long orders;
 
-	/* If khugepaged is scanning an anonymous vma, allow mTHP collapse */
+	/*
+	 * If khugepaged is scanning an anonymous or shmem vma,
+	 * allow mTHP collapse.
+	 */
 	if ((tva_flags == TVA_KHUGEPAGED) && vma_is_anonymous(vma))
 		orders = THP_ORDERS_ALL_ANON;
+	else if ((tva_flags == TVA_KHUGEPAGED) && vma_is_shmem(vma))
+		orders = THP_ORDERS_ALL_FILE_DEFAULT;
 	else
 		orders = BIT(HPAGE_PMD_ORDER);
 
-- 
2.47.3