[RFC PATCH 2/5] mm: shmem: add an 'order' parameter for shmem_alloc_hugefolio()

[Baolin Wang]

Add a new parameter to specify the huge page order for shmem_alloc_hugefolio(),
as a preparation to supoort mTHP.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
---
 mm/shmem.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index fa2a0ed97507..893c88efc45f 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1604,14 +1604,14 @@ static gfp_t limit_gfp_mask(gfp_t huge_gfp, gfp_t limit_gfp)
 }
 
 static struct folio *shmem_alloc_hugefolio(gfp_t gfp,
-		struct shmem_inode_info *info, pgoff_t index)
+		struct shmem_inode_info *info, pgoff_t index, int order)
 {
 	struct mempolicy *mpol;
 	pgoff_t ilx;
 	struct page *page;
 
-	mpol = shmem_get_pgoff_policy(info, index, HPAGE_PMD_ORDER, &ilx);
-	page = alloc_pages_mpol(gfp, HPAGE_PMD_ORDER, mpol, ilx, numa_node_id());
+	mpol = shmem_get_pgoff_policy(info, index, order, &ilx);
+	page = alloc_pages_mpol(gfp, order, mpol, ilx, numa_node_id());
 	mpol_cond_put(mpol);
 
 	return page_rmappable_folio(page);
@@ -1639,13 +1639,14 @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp,
 	struct shmem_inode_info *info = SHMEM_I(inode);
 	struct folio *folio;
 	long pages;
-	int error;
+	int error, order;
 
 	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
 		huge = false;
 
 	if (huge) {
 		pages = HPAGE_PMD_NR;
+		order = HPAGE_PMD_ORDER;
 		index = round_down(index, HPAGE_PMD_NR);
 
 		/*
@@ -1660,7 +1661,7 @@ static struct folio *shmem_alloc_and_add_folio(gfp_t gfp,
 				index + HPAGE_PMD_NR - 1, XA_PRESENT))
 			return ERR_PTR(-E2BIG);
 
-		folio = shmem_alloc_hugefolio(gfp, info, index);
+		folio = shmem_alloc_hugefolio(gfp, info, index, order);
 		if (!folio)
 			count_vm_event(THP_FILE_FALLBACK);
 	} else {
-- 
2.39.3