[RFC PATCH 16/18] mm: Use a folio in __collapse_huge_page_copy_succeeded()

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

These pages are all chained together through the lru list, so we know
they're folios.  Use the folio APIs to save three hidden calls to
compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/khugepaged.c | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 88433cc25d8a..afc94c281035 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -685,8 +685,7 @@ static void __collapse_huge_page_copy_succeeded(pte_t *pte,
 						spinlock_t *ptl,
 						struct list_head *compound_pagelist)
 {
-	struct page *src_page;
-	struct page *tmp;
+	struct folio *src, *tmp;
 	pte_t *_pte;
 	pte_t pteval;
 
@@ -705,7 +704,7 @@ static void __collapse_huge_page_copy_succeeded(pte_t *pte,
 				ksm_might_unmap_zero_page(vma->vm_mm, pteval);
 			}
 		} else {
-			src_page = pte_page(pteval);
+			struct page *src_page = pte_page(pteval);
 			if (!PageCompound(src_page))
 				release_pte_page(src_page);
 			/*
@@ -721,14 +720,13 @@ static void __collapse_huge_page_copy_succeeded(pte_t *pte,
 		}
 	}
 
-	list_for_each_entry_safe(src_page, tmp, compound_pagelist, lru) {
-		list_del(&src_page->lru);
-		mod_node_page_state(page_pgdat(src_page),
-				    NR_ISOLATED_ANON + page_is_file_lru(src_page),
-				    -compound_nr(src_page));
-		unlock_page(src_page);
-		free_swap_cache(src_page);
-		putback_lru_page(src_page);
+	list_for_each_entry_safe(src, tmp, compound_pagelist, lru) {
+		list_del(&src->lru);
+		node_stat_sub_folio(src, NR_ISOLATED_ANON +
+				folio_is_file_lru(src));
+		folio_unlock(src);
+		free_swap_cache(&src->page);
+		folio_putback_lru(src);
 	}
 }
 
-- 
2.40.1