linux-kernel - [PATCH v3 03/12] hugetlb: Remove a few calls to page

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Date:   Fri, 15 Sep 2023 15:15:36 -0700
From:   Mike Kravetz <mike.kravetz@...cle.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     Muchun Song <songmuchun@...edance.com>,
        Joao Martins <joao.m.martins@...cle.com>,
        Oscar Salvador <osalvador@...e.de>,
        David Hildenbrand <david@...hat.com>,
        Miaohe Lin <linmiaohe@...wei.com>,
        David Rientjes <rientjes@...gle.com>,
        Anshuman Khandual <anshuman.khandual@....com>,
        Naoya Horiguchi <naoya.horiguchi@...ux.dev>,
        Barry Song <song.bao.hua@...ilicon.com>,
        Michal Hocko <mhocko@...e.com>,
        Matthew Wilcox <willy@...radead.org>,
        Xiongchun Duan <duanxiongchun@...edance.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Sidhartha Kumar <sidhartha.kumar@...cle.com>
Subject: [PATCH v3 03/12] hugetlb: Remove a few calls to page_folio()

From: "Matthew Wilcox (Oracle)" <willy@...radead.org>

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.

Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
Reviewed-by: Mike Kravetz <mike.kravetz@...cle.com>
Reviewed-by: Muchun Song <songmuchun@...edance.com>
Cc: Sidhartha Kumar <sidhartha.kumar@...cle.com>
---
 mm/hugetlb.c | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 6c6f19cc6046..7bbdc71fb34d 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1829,11 +1829,9 @@ static void update_and_free_hugetlb_folio(struct hstate *h, struct folio *folio,
 
 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();
 	}
@@ -2208,8 +2206,7 @@ static struct page *remove_pool_huge_page(struct hstate *h,
 						 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) {
@@ -2219,15 +2216,14 @@ static struct page *remove_pool_huge_page(struct hstate *h,
 		 */
 		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;
 }
 
 /*
@@ -3343,15 +3339,15 @@ static void try_to_free_low(struct hstate *h, unsigned long count,
 	 * 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);
 		}
 	}
 
-- 
2.41.0