[PATCH v2 6/8] mm: migrate: use a folio in add_page_for_migration()

[Kefeng Wang]

Use a folio in add_page_for_migration() to save compound_head() calls.

Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
 mm/migrate.c | 40 +++++++++++++++++++---------------------
 1 file changed, 19 insertions(+), 21 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index b715cd59bdec..73572d5a5cd4 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2057,6 +2057,7 @@ static int add_page_for_migration(struct mm_struct *mm, const void __user *p,
 	struct vm_area_struct *vma;
 	unsigned long addr;
 	struct page *page;
+	struct folio *folio;
 	int err;
 	bool isolated;
 
@@ -2079,45 +2080,42 @@ static int add_page_for_migration(struct mm_struct *mm, const void __user *p,
 	if (!page)
 		goto out;
 
-	if (is_zone_device_page(page))
-		goto out_putpage;
+	folio = page_folio(page);
+	if (folio_is_zone_device(folio))
+		goto out_putfolio;
 
 	err = 0;
-	if (page_to_nid(page) == node)
-		goto out_putpage;
+	if (folio_nid(folio) == node)
+		goto out_putfolio;
 
 	err = -EACCES;
 	if (page_mapcount(page) > 1 && !migrate_all)
-		goto out_putpage;
+		goto out_putfolio;
 
-	if (PageHuge(page)) {
+	if (folio_test_hugetlb(folio)) {
 		if (PageHead(page)) {
-			isolated = isolate_hugetlb(page_folio(page), pagelist);
+			isolated = isolate_hugetlb(folio, pagelist);
 			err = isolated ? 1 : -EBUSY;
 		}
 	} else {
-		struct page *head;
-
-		head = compound_head(page);
-		isolated = isolate_lru_page(head);
+		isolated = folio_isolate_lru(folio);
 		if (!isolated) {
 			err = -EBUSY;
-			goto out_putpage;
+			goto out_putfolio;
 		}
 
 		err = 1;
-		list_add_tail(&head->lru, pagelist);
-		mod_node_page_state(page_pgdat(head),
-			NR_ISOLATED_ANON + page_is_file_lru(head),
-			thp_nr_pages(head));
+		list_add_tail(&folio->lru, pagelist);
+		node_stat_mod_folio(folio,
+			NR_ISOLATED_ANON + folio_is_file_lru(folio),
+			folio_nr_pages(folio));
 	}
-out_putpage:
+out_putfolio:
 	/*
-	 * Either remove the duplicate refcount from
-	 * isolate_lru_page() or drop the page ref if it was
-	 * not isolated.
+	 * Either remove the duplicate refcount from folio_isolate_lru()
+	 * or drop the folio ref if it was not isolated.
 	 */
-	put_page(page);
+	folio_put(folio);
 out:
 	mmap_read_unlock(mm);
 	return err;
-- 
2.41.0