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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	linux-kernel@vger.kernel.org
Subject: [RFC PATCH 05/11] mm: Add unlock_folio
Date: Tue,  8 Dec 2020 19:46:47 +0000	[thread overview]
Message-ID: <20201208194653.19180-6-willy@infradead.org> (raw)
In-Reply-To: <20201208194653.19180-1-willy@infradead.org>

Convert unlock_page() to call unlock_folio().  By using a folio we avoid
doing a repeated compound_head() This shortens the function from 120
bytes to 76 bytes.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/pagemap.h | 16 +++++++++++++++-
 mm/filemap.c            | 27 ++++++++++-----------------
 2 files changed, 25 insertions(+), 18 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 46d4b1704770..64ae1bb62765 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -588,7 +588,21 @@ extern int __lock_page_killable(struct page *page);
 extern int __lock_page_async(struct page *page, struct wait_page_queue *wait);
 extern int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
 				unsigned int flags);
-extern void unlock_page(struct page *page);
+extern void unlock_folio(struct folio *folio);
+
+/**
+ * unlock_page - Unlock a locked page.
+ * @page: The page.
+ *
+ * Unlocks the page and wakes up any thread sleeping on the page lock.
+ *
+ * Context: May be called from interrupt or process context.  May not be
+ * called from NMI context.
+ */
+static inline void unlock_page(struct page *page)
+{
+	return unlock_folio(page_folio(page));
+}
 
 /*
  * Return true if the page was successfully locked
diff --git a/mm/filemap.c b/mm/filemap.c
index 78090ee08ac2..de8372307b33 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1443,29 +1443,22 @@ static inline bool clear_bit_unlock_is_negative_byte(long nr, volatile void *mem
 #endif
 
 /**
- * unlock_page - unlock a locked page
- * @page: the page
+ * unlock_folio - Unlock a locked folio.
+ * @folio: The folio.
  *
- * Unlocks the page and wakes up sleepers in wait_on_page_locked().
- * Also wakes sleepers in wait_on_page_writeback() because the wakeup
- * mechanism between PageLocked pages and PageWriteback pages is shared.
- * But that's OK - sleepers in wait_on_page_writeback() just go back to sleep.
+ * Unlocks the folio and wakes up any thread sleeping on the page lock.
  *
- * Note that this depends on PG_waiters being the sign bit in the byte
- * that contains PG_locked - thus the BUILD_BUG_ON(). That allows us to
- * clear the PG_locked bit and test PG_waiters at the same time fairly
- * portably (architectures that do LL/SC can test any bit, while x86 can
- * test the sign bit).
+ * Context: May be called from interrupt or process context.  May not be
+ * called from NMI context.
  */
-void unlock_page(struct page *page)
+void unlock_folio(struct folio *folio)
 {
 	BUILD_BUG_ON(PG_waiters != 7);
-	page = compound_head(page);
-	VM_BUG_ON_PAGE(!PageLocked(page), page);
-	if (clear_bit_unlock_is_negative_byte(PG_locked, &page->flags))
-		wake_up_page_bit(page, PG_locked);
+	VM_BUG_ON_PAGE(!FolioLocked(folio), &folio->page);
+	if (clear_bit_unlock_is_negative_byte(PG_locked, folio_flags(folio)))
+		wake_up_page_bit(&folio->page, PG_locked);
 }
-EXPORT_SYMBOL(unlock_page);
+EXPORT_SYMBOL(unlock_folio);
 
 /**
  * end_page_writeback - end writeback against a page
-- 
2.29.2


  parent reply	other threads:[~2020-12-08 20:23 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-08 19:46 [RFC PATCH 00/11] Page folios Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 01/11] mm: Introduce struct folio Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 02/11] mm: Add put_folio Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 03/11] mm: Add get_folio Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 04/11] mm: Create FolioFlags Matthew Wilcox (Oracle)
2020-12-08 19:46 ` Matthew Wilcox (Oracle) [this message]
2020-12-08 19:46 ` [RFC PATCH 06/11] mm: Add lock_folio Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 07/11] mm: Add lock_folio_killable Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 08/11] mm/filemap: Convert end_page_writeback to use a folio Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 09/11] mm/filemap: Convert mapping_get_entry and pagecache_get_page to folio Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 10/11] mm/filemap: Add folio_add_to_page_cache Matthew Wilcox (Oracle)
2020-12-11  8:32   ` Nikolay Borisov
2020-12-08 19:46 ` [RFC PATCH 11/11] mm/swap: Convert rotate_reclaimable_page to folio Matthew Wilcox (Oracle)

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