linux-kernel - [PATCH v4 2/7] mm/page_owner: use order instead of nr in split_page

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Date: Tue, 13 Feb 2024 16:55:15 -0500
From: Zi Yan <zi.yan@...t.com>
To: "Pankaj Raghav (Samsung)" <kernel@...kajraghav.com>,
	linux-mm@...ck.org
Cc: Zi Yan <ziy@...dia.com>,
	"Matthew Wilcox (Oracle)" <willy@...radead.org>,
	David Hildenbrand <david@...hat.com>,
	Yang Shi <shy828301@...il.com>,
	Yu Zhao <yuzhao@...gle.com>,
	"Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
	Ryan Roberts <ryan.roberts@....com>,
	Michal Koutný <mkoutny@...e.com>,
	Roman Gushchin <roman.gushchin@...ux.dev>,
	"Zach O'Keefe" <zokeefe@...gle.com>,
	Hugh Dickins <hughd@...gle.com>,
	Mcgrof Chamberlain <mcgrof@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org,
	cgroups@...r.kernel.org,
	linux-fsdevel@...r.kernel.org,
	linux-kselftest@...r.kernel.org
Subject: [PATCH v4 2/7] mm/page_owner: use order instead of nr in split_page_owner()

From: Zi Yan <ziy@...dia.com>

We do not have non power of two pages, using nr is error prone if nr
is not power-of-two. Use page order instead.

Signed-off-by: Zi Yan <ziy@...dia.com>
---
 include/linux/page_owner.h | 8 ++++----
 mm/huge_memory.c           | 2 +-
 mm/page_alloc.c            | 4 ++--
 mm/page_owner.c            | 3 ++-
 4 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h
index 119a0c9d2a8b..d7878523adfc 100644
--- a/include/linux/page_owner.h
+++ b/include/linux/page_owner.h
@@ -11,7 +11,7 @@ extern struct page_ext_operations page_owner_ops;
 extern void __reset_page_owner(struct page *page, unsigned short order);
 extern void __set_page_owner(struct page *page,
 			unsigned short order, gfp_t gfp_mask);
-extern void __split_page_owner(struct page *page, unsigned int nr);
+extern void __split_page_owner(struct page *page, int order);
 extern void __folio_copy_owner(struct folio *newfolio, struct folio *old);
 extern void __set_page_owner_migrate_reason(struct page *page, int reason);
 extern void __dump_page_owner(const struct page *page);
@@ -31,10 +31,10 @@ static inline void set_page_owner(struct page *page,
 		__set_page_owner(page, order, gfp_mask);
 }
 
-static inline void split_page_owner(struct page *page, unsigned int nr)
+static inline void split_page_owner(struct page *page, int order)
 {
 	if (static_branch_unlikely(&page_owner_inited))
-		__split_page_owner(page, nr);
+		__split_page_owner(page, order);
 }
 static inline void folio_copy_owner(struct folio *newfolio, struct folio *old)
 {
@@ -60,7 +60,7 @@ static inline void set_page_owner(struct page *page,
 {
 }
 static inline void split_page_owner(struct page *page,
-			unsigned short order)
+			int order)
 {
 }
 static inline void folio_copy_owner(struct folio *newfolio, struct folio *folio)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 0cd5fba0923c..f079b02f1f59 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2919,7 +2919,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 	unlock_page_lruvec(lruvec);
 	/* Caller disabled irqs, so they are still disabled here */
 
-	split_page_owner(head, nr);
+	split_page_owner(head, order);
 
 	/* See comment in __split_huge_page_tail() */
 	if (PageAnon(head)) {
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7c927b84e16c..b6e8fe6fed67 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2652,7 +2652,7 @@ void split_page(struct page *page, unsigned int order)
 
 	for (i = 1; i < (1 << order); i++)
 		set_page_refcounted(page + i);
-	split_page_owner(page, 1 << order);
+	split_page_owner(page, order);
 	split_page_memcg(page, order);
 }
 EXPORT_SYMBOL_GPL(split_page);
@@ -4837,7 +4837,7 @@ static void *make_alloc_exact(unsigned long addr, unsigned int order,
 		struct page *page = virt_to_page((void *)addr);
 		struct page *last = page + nr;
 
-		split_page_owner(page, 1 << order);
+		split_page_owner(page, order);
 		split_page_memcg(page, order);
 		while (page < --last)
 			set_page_refcounted(last);
diff --git a/mm/page_owner.c b/mm/page_owner.c
index c4f9e5506e93..1319e402c2cf 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -292,11 +292,12 @@ void __set_page_owner_migrate_reason(struct page *page, int reason)
 	page_ext_put(page_ext);
 }
 
-void __split_page_owner(struct page *page, unsigned int nr)
+void __split_page_owner(struct page *page, int order)
 {
 	int i;
 	struct page_ext *page_ext = page_ext_get(page);
 	struct page_owner *page_owner;
+	unsigned int nr = 1 << order;
 
 	if (unlikely(!page_ext))
 		return;
-- 
2.43.0