linux-kernel - [PATCH 4/5] hugetlb: convert PageHugeTemporary() to HP

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Message-Id: <20210116003105.182918-5-mike.kravetz@oracle.com>
Date:   Fri, 15 Jan 2021 16:31:04 -0800
From:   Mike Kravetz <mike.kravetz@...cle.com>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:     Michal Hocko <mhocko@...nel.org>,
        Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
        Muchun Song <songmuchun@...edance.com>,
        David Hildenbrand <david@...hat.com>,
        Oscar Salvador <osalvador@...e.de>,
        Matthew Wilcox <willy@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mike Kravetz <mike.kravetz@...cle.com>
Subject: [PATCH 4/5] hugetlb: convert PageHugeTemporary() to HP_Temporary flag

Use new hugetlb specific flag HP_Temporary flag to replace the
PageHugeTemporary() interfaces.

Signed-off-by: Mike Kravetz <mike.kravetz@...cle.com>
---
 include/linux/hugetlb.h |  5 +++++
 mm/hugetlb.c            | 36 +++++++-----------------------------
 2 files changed, 12 insertions(+), 29 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index e7157cf9967f..166825c85875 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -483,10 +483,15 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
  * HP_Migratable - Set after a newly allocated page is added to the page
  *	cache and/or page tables.  Indicates the page is a candidate for
  *	migration.
+ * HP_Temporary - Set on a page that is temporarily allocated from the buddy
+ *	allocator.  Typically used for migration target pages when no pages
+ *	are available in the pool.  The hugetlb free page path will
+ *	immediately free pages with this flag set to the buddy allocator.
  */
 enum hugetlb_page_flags {
 	HP_Restore_Reserve = 0,
 	HP_Migratable,
+	HP_Temporary,
 };
 
 #ifdef CONFIG_HUGETLB_PAGE
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 31e896c70ba0..53e9168a97bd 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1353,28 +1353,6 @@ struct hstate *size_to_hstate(unsigned long size)
 	return NULL;
 }
 
-/*
- * Internal hugetlb specific page flag. Do not use outside of the hugetlb
- * code
- */
-static inline bool PageHugeTemporary(struct page *page)
-{
-	if (!PageHuge(page))
-		return false;
-
-	return (unsigned long)page[2].mapping == -1U;
-}
-
-static inline void SetPageHugeTemporary(struct page *page)
-{
-	page[2].mapping = (void *)-1U;
-}
-
-static inline void ClearPageHugeTemporary(struct page *page)
-{
-	page[2].mapping = NULL;
-}
-
 static void __free_huge_page(struct page *page)
 {
 	/*
@@ -1422,9 +1400,9 @@ static void __free_huge_page(struct page *page)
 	if (restore_reserve)
 		h->resv_huge_pages++;
 
-	if (PageHugeTemporary(page)) {
+	if (hugetlb_test_page_flag(page, HP_Temporary)) {
 		list_del(&page->lru);
-		ClearPageHugeTemporary(page);
+		hugetlb_clear_page_flag(page, HP_Temporary);
 		update_and_free_page(h, page);
 	} else if (h->surplus_huge_pages_node[nid]) {
 		/* remove the page from active list */
@@ -1863,7 +1841,7 @@ static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
 	 * codeflow
 	 */
 	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
-		SetPageHugeTemporary(page);
+		hugetlb_set_page_flag(page, HP_Temporary);
 		spin_unlock(&hugetlb_lock);
 		put_page(page);
 		return NULL;
@@ -1894,7 +1872,7 @@ static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
 	 * We do not account these pages as surplus because they are only
 	 * temporary and will be released properly on the last reference
 	 */
-	SetPageHugeTemporary(page);
+	hugetlb_set_page_flag(page, HP_Temporary);
 
 	return page;
 }
@@ -5608,12 +5586,12 @@ void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
 	 * here as well otherwise the global surplus count will not match
 	 * the per-node's.
 	 */
-	if (PageHugeTemporary(newpage)) {
+	if (hugetlb_test_page_flag(newpage, HP_Temporary)) {
 		int old_nid = page_to_nid(oldpage);
 		int new_nid = page_to_nid(newpage);
 
-		SetPageHugeTemporary(oldpage);
-		ClearPageHugeTemporary(newpage);
+		hugetlb_set_page_flag(oldpage, HP_Temporary);
+		hugetlb_clear_page_flag(newpage, HP_Temporary);
 
 		spin_lock(&hugetlb_lock);
 		if (h->surplus_huge_pages_node[old_nid]) {
-- 
2.29.2