[02/25] mm: Add put_folio

Commit Message

Matthew Wilcox Dec. 16, 2020, 6:23 p.m. UTC

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) <[e-mail]>
---
 include/linux/mm.h | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

Patch

diff --git a/include/linux/mm.h b/include/linux/mm.h
index ed20fd0c6169..a9191dc250a6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1194,9 +1194,15 @@  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
@@ -1204,13 +1210,12 @@  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);
 }
 
 /*