linux-kernel - [PATCH v2 6/6] mm/mm_init: initialize page->_mapcount directly in __init_single

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Date: Wed, 29 May 2024 13:19:04 +0200
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org,
	David Hildenbrand <david@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Matthew Wilcox (Oracle)" <willy@...radead.org>,
	Mike Rapoport <rppt@...nel.org>,
	Minchan Kim <minchan@...nel.org>,
	Sergey Senozhatsky <senozhatsky@...omium.org>,
	Hyeonggon Yoo <42.hyeyoo@...il.com>
Subject: [PATCH v2 6/6] mm/mm_init: initialize page->_mapcount directly in __init_single_page()

Let's simply reinitialize the page->_mapcount directly. We can now
get rid of page_mapcount_reset().

Signed-off-by: David Hildenbrand <david@...hat.com>
---
 include/linux/mm.h | 5 -----
 mm/mm_init.c       | 2 +-
 2 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index eebfce8f58bca..c41c82bcbec2f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1206,11 +1206,6 @@ static inline int folio_entire_mapcount(const struct folio *folio)
 	return atomic_read(&folio->_entire_mapcount) + 1;
 }
 
-static inline void page_mapcount_reset(struct page *page)
-{
-	atomic_set(&(page)->_mapcount, -1);
-}
-
 /**
  * page_mapcount() - Number of times this precise page is mapped.
  * @page: The page.
diff --git a/mm/mm_init.c b/mm/mm_init.c
index e0023aa685556..426314eeecec3 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -568,7 +568,7 @@ void __meminit __init_single_page(struct page *page, unsigned long pfn,
 	mm_zero_struct_page(page);
 	set_page_links(page, zone, nid, pfn);
 	init_page_count(page);
-	page_mapcount_reset(page);
+	atomic_set(&page->_mapcount, -1);
 	page_cpupid_reset_last(page);
 	page_kasan_tag_reset(page);
 
-- 
2.45.1