patches/old/hugetlb-remove-a-few-calls-to-page_folio.patch

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: hugetlb: remove a few calls to page_folio()
Date: Thu, 24 Aug 2023 15:13:24 +0100

Anything found on a linked list threaded through ->lru is guaranteed to be
a folio as the compound_head found in a tail page overlaps the ->lru
member of struct page.  So we can pull folios directly off these lists no
matter whether pages or folios were added to the list.

Link: https://lkml.kernel.org/r/20230824141325.2704553-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/hugetlb.c |   26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

--- a/mm/hugetlb.c~hugetlb-remove-a-few-calls-to-page_folio
+++ a/mm/hugetlb.c
@@ -1836,11 +1836,9 @@ static void update_and_free_hugetlb_foli
 
 static void update_and_free_pages_bulk(struct hstate *h, struct list_head *list)
 {
-	struct page *page, *t_page;
-	struct folio *folio;
+	struct folio *folio, *t_folio;
 
-	list_for_each_entry_safe(page, t_page, list, lru) {
-		folio = page_folio(page);
+	list_for_each_entry_safe(folio, t_folio, list, lru) {
 		update_and_free_hugetlb_folio(h, folio, false);
 		cond_resched();
 	}
@@ -2229,8 +2227,7 @@ static struct page *remove_pool_huge_pag
 						 bool acct_surplus)
 {
 	int nr_nodes, node;
-	struct page *page = NULL;
-	struct folio *folio;
+	struct folio *folio = NULL;
 
 	lockdep_assert_held(&hugetlb_lock);
 	for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
@@ -2240,15 +2237,14 @@ static struct page *remove_pool_huge_pag
 		 */
 		if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
 		    !list_empty(&h->hugepage_freelists[node])) {
-			page = list_entry(h->hugepage_freelists[node].next,
-					  struct page, lru);
-			folio = page_folio(page);
+			folio = list_entry(h->hugepage_freelists[node].next,
+					  struct folio, lru);
 			remove_hugetlb_folio(h, folio, acct_surplus);
 			break;
 		}
 	}
 
-	return page;
+	return &folio->page;
 }
 
 /*
@@ -3414,15 +3410,15 @@ static void try_to_free_low(struct hstat
 	 * Collect pages to be freed on a list, and free after dropping lock
 	 */
 	for_each_node_mask(i, *nodes_allowed) {
-		struct page *page, *next;
+		struct folio *folio, *next;
 		struct list_head *freel = &h->hugepage_freelists[i];
-		list_for_each_entry_safe(page, next, freel, lru) {
+		list_for_each_entry_safe(folio, next, freel, lru) {
 			if (count >= h->nr_huge_pages)
 				goto out;
-			if (PageHighMem(page))
+			if (folio_test_highmem(folio))
 				continue;
-			remove_hugetlb_folio(h, page_folio(page), false);
-			list_add(&page->lru, &page_list);
+			remove_hugetlb_folio(h, folio, false);
+			list_add(&folio->lru, &page_list);
 		}
 	}
 
_