Thread (28 messages) flat view 28 messages, 1 author, 2021-01-18
STALE2060d

Revision v2 of 5 in this series.

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[PATCH v2 05/27] mm: Add put_folio

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Date: 2021-01-18 17:03:55
Also in: linux-fsdevel, lkml
Subsystem: memory management - core, the rest · Maintainers: Andrew Morton, David Hildenbrand, Linus Torvalds

If we know we have a folio, we can call put_folio() instead of put_page()
and save the overhead of calling compound_head().  Also skips the
devmap checks.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/mm.h | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5b071c226fd6..4d135b62a2b6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1217,9 +1217,15 @@ static inline __must_check bool try_get_page(struct page *page)
 	return true;
 }
 
+static inline void put_folio(struct folio *folio)
+{
+	if (put_page_testzero(&folio->page))
+		__put_page(&folio->page);
+}
+
 static inline void put_page(struct page *page)
 {
-	page = compound_head(page);
+	struct folio *folio = page_folio(page);
 
 	/*
 	 * For devmap managed pages we need to catch refcount transition from
@@ -1227,13 +1233,12 @@ static inline void put_page(struct page *page)
 	 * need to inform the device driver through callback. See
 	 * include/linux/memremap.h and HMM for details.
 	 */
-	if (page_is_devmap_managed(page)) {
-		put_devmap_managed_page(page);
+	if (page_is_devmap_managed(&folio->page)) {
+		put_devmap_managed_page(&folio->page);
 		return;
 	}
 
-	if (put_page_testzero(page))
-		__put_page(page);
+	put_folio(folio);
 }
 
 /*
-- 
2.29.2

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