linux-kernel - [PATCH v2 5/9] mm/hugetlb: convert isolate_or_dissolve_huge

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Date:   Tue,  1 Nov 2022 15:30:55 -0700
From:   Sidhartha Kumar <sidhartha.kumar@...cle.com>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:     akpm@...ux-foundation.org, songmuchun@...edance.com,
        mike.kravetz@...cle.com, willy@...radead.org,
        almasrymina@...gle.com, linmiaohe@...wei.com,
        minhquangbui99@...il.com, aneesh.kumar@...ux.ibm.com,
        Sidhartha Kumar <sidhartha.kumar@...cle.com>
Subject: [PATCH v2 5/9] mm/hugetlb: convert isolate_or_dissolve_huge_page to folios

Removes a call to compound_head() by using a folio when operating on the
head page of a hugetlb compound page.

Signed-off-by: Sidhartha Kumar <sidhartha.kumar@...cle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@...cle.com>
---
 mm/hugetlb.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 2a48feadb41c..bcc39d2613b2 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2815,7 +2815,7 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
 int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list)
 {
 	struct hstate *h;
-	struct page *head;
+	struct folio *folio = page_folio(page);
 	int ret = -EBUSY;
 
 	/*
@@ -2824,9 +2824,8 @@ int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list)
 	 * Return success when racing as if we dissolved the page ourselves.
 	 */
 	spin_lock_irq(&hugetlb_lock);
-	if (PageHuge(page)) {
-		head = compound_head(page);
-		h = page_hstate(head);
+	if (folio_test_hugetlb(folio)) {
+		h = folio_hstate(folio);
 	} else {
 		spin_unlock_irq(&hugetlb_lock);
 		return 0;
@@ -2841,10 +2840,10 @@ int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list)
 	if (hstate_is_gigantic(h))
 		return -ENOMEM;
 
-	if (page_count(head) && !isolate_hugetlb(head, list))
+	if (folio_ref_count(folio) && !isolate_hugetlb(&folio->page, list))
 		ret = 0;
-	else if (!page_count(head))
-		ret = alloc_and_dissolve_huge_page(h, head, list);
+	else if (!folio_ref_count(folio))
+		ret = alloc_and_dissolve_huge_page(h, &folio->page, list);
 
 	return ret;
 }
-- 
2.31.1