linux-kernel - [PATCHv2 05/14] mm: Move set/clear_compound_head() next to compound

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Message-ID: <20251218150949.721480-6-kas@kernel.org>
Date: Thu, 18 Dec 2025 15:09:36 +0000
From: Kiryl Shutsemau <kas@...nel.org>
To: Andrew Morton <akpm@...ux-foundation.org>,
	Muchun Song <muchun.song@...ux.dev>,
	David Hildenbrand <david@...nel.org>,
	Matthew Wilcox <willy@...radead.org>,
	Usama Arif <usamaarif642@...il.com>,
	Frank van der Linden <fvdl@...gle.com>
Cc: Oscar Salvador <osalvador@...e.de>,
	Mike Rapoport <rppt@...nel.org>,
	Vlastimil Babka <vbabka@...e.cz>,
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
	Zi Yan <ziy@...dia.com>,
	Baoquan He <bhe@...hat.com>,
	Michal Hocko <mhocko@...e.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Jonathan Corbet <corbet@....net>,
	kernel-team@...a.com,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	linux-doc@...r.kernel.org,
	Kiryl Shutsemau <kas@...nel.org>
Subject: [PATCHv2 05/14] mm: Move set/clear_compound_head() next to compound_head()

Move set_compound_head() and clear_compound_head() to be adjacent to the
compound_head() function in page-flags.h.

These functions encode and decode the same compound_info field, so
keeping them together makes it easier to verify their logic is
consistent, especially when the encoding changes.

Signed-off-by: Kiryl Shutsemau <kas@...nel.org>
---
 include/linux/page-flags.h | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 72c933a43b6a..0de7db7efb00 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -290,6 +290,18 @@ static __always_inline unsigned long _compound_head(const struct page *page)
 
 #define compound_head(page)	((typeof(page))_compound_head(page))
 
+static __always_inline void set_compound_head(struct page *page,
+					      const struct page *head,
+					      unsigned int order)
+{
+	WRITE_ONCE(page->compound_info, (unsigned long)head + 1);
+}
+
+static __always_inline void clear_compound_head(struct page *page)
+{
+	WRITE_ONCE(page->compound_info, 0);
+}
+
 /**
  * page_folio - Converts from page to folio.
  * @p: The page.
@@ -865,18 +877,6 @@ static inline bool folio_test_large(const struct folio *folio)
 	return folio_test_head(folio);
 }
 
-static __always_inline void set_compound_head(struct page *page,
-					      const struct page *head,
-					      unsigned int order)
-{
-	WRITE_ONCE(page->compound_info, (unsigned long)head + 1);
-}
-
-static __always_inline void clear_compound_head(struct page *page)
-{
-	WRITE_ONCE(page->compound_info, 0);
-}
-
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 static inline void ClearPageCompound(struct page *page)
 {
-- 
2.51.2