mm/page_owner: use order instead of nr in split_page_owner()

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.

Link: https://lkml.kernel.org/r/20240226205534.1603748-5-zi.yan@sent.comSigned-off-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michal Koutny <mkoutny@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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)
 {
@@ -59,8 +59,7 @@ static inline void set_page_owner(struct page *page,
 			unsigned int order, gfp_t gfp_mask)
 {
 }
-static inline void split_page_owner(struct page *page,
-			unsigned short order)
+static inline void split_page_owner(struct page *page, int order)
 {
 }
 static inline void folio_copy_owner(struct folio *newfolio, struct folio *folio)

mm/huge_memory.c

@@ -2933,7 +2933,7 @@ 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)) {

mm/page_alloc.c

@@ -2616,7 +2616,7 @@ 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);
@@ -4801,7 +4801,7 @@ 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);

mm/page_owner.c

@@ -306,11 +306,12 @@ 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;