diff mbox series

[v10,19/33] mm/filemap: Add folio_lock

Message ID 20210511214735.1836149-20-willy@infradead.org (mailing list archive)
State New
Headers show
Series Memory folios | expand

Commit Message

Matthew Wilcox May 11, 2021, 9:47 p.m. UTC
This is like lock_page() but for use by callers who know they have a folio.
Convert __lock_page() to be __folio_lock().  This saves one call to
compound_head() per contended call to lock_page().

Saves 362 bytes of text; mostly from improved register allocation and
inlining decisions.  __folio_lock is 59 bytes while __lock_page was 79.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Layton <jlayton@kernel.org>
---
 include/linux/pagemap.h | 24 +++++++++++++++++++-----
 mm/filemap.c            | 29 +++++++++++++++--------------
 2 files changed, 34 insertions(+), 19 deletions(-)

Comments

Vlastimil Babka May 18, 2021, 10:26 a.m. UTC | #1
On 5/11/21 11:47 PM, Matthew Wilcox (Oracle) wrote:
> This is like lock_page() but for use by callers who know they have a folio.
> Convert __lock_page() to be __folio_lock().  This saves one call to
> compound_head() per contended call to lock_page().
> 
> Saves 362 bytes of text; mostly from improved register allocation and
> inlining decisions.  __folio_lock is 59 bytes while __lock_page was 79.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Acked-by: Jeff Layton <jlayton@kernel.org>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

> ---
>  include/linux/pagemap.h | 24 +++++++++++++++++++-----
>  mm/filemap.c            | 29 +++++++++++++++--------------
>  2 files changed, 34 insertions(+), 19 deletions(-)
> 
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index 8dbba0074536..9a78397609b8 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -638,7 +638,7 @@ static inline bool wake_page_match(struct wait_page_queue *wait_page,
>  	return true;
>  }
>  
> -extern void __lock_page(struct page *page);
> +void __folio_lock(struct folio *folio);
>  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,
> @@ -646,13 +646,24 @@ extern int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
>  void unlock_page(struct page *page);
>  void folio_unlock(struct folio *folio);
>  
> +static inline bool folio_trylock(struct folio *folio)
> +{
> +	return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0)));
> +}
> +
>  /*
>   * Return true if the page was successfully locked
>   */
>  static inline int trylock_page(struct page *page)
>  {
> -	page = compound_head(page);
> -	return (likely(!test_and_set_bit_lock(PG_locked, &page->flags)));
> +	return folio_trylock(page_folio(page));
> +}
> +
> +static inline void folio_lock(struct folio *folio)
> +{
> +	might_sleep();
> +	if (!folio_trylock(folio))
> +		__folio_lock(folio);
>  }
>  
>  /*
> @@ -660,9 +671,12 @@ static inline int trylock_page(struct page *page)
>   */
>  static inline void lock_page(struct page *page)
>  {
> +	struct folio *folio;
>  	might_sleep();
> -	if (!trylock_page(page))
> -		__lock_page(page);
> +
> +	folio = page_folio(page);
> +	if (!folio_trylock(folio))
> +		__folio_lock(folio);
>  }
>  
>  /*
> diff --git a/mm/filemap.c b/mm/filemap.c
> index e7a6a58d6cd9..c6e5ba176764 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -1187,7 +1187,7 @@ static void wake_up_page(struct page *page, int bit)
>   */
>  enum behavior {
>  	EXCLUSIVE,	/* Hold ref to page and take the bit when woken, like
> -			 * __lock_page() waiting on then setting PG_locked.
> +			 * __folio_lock() waiting on then setting PG_locked.
>  			 */
>  	SHARED,		/* Hold ref to page and check the bit when woken, like
>  			 * wait_on_page_writeback() waiting on PG_writeback.
> @@ -1576,17 +1576,16 @@ void page_endio(struct page *page, bool is_write, int err)
>  EXPORT_SYMBOL_GPL(page_endio);
>  
>  /**
> - * __lock_page - get a lock on the page, assuming we need to sleep to get it
> - * @__page: the page to lock
> + * __folio_lock - Get a lock on the folio, assuming we need to sleep to get it.
> + * @folio: The folio to lock
>   */
> -void __lock_page(struct page *__page)
> +void __folio_lock(struct folio *folio)
>  {
> -	struct page *page = compound_head(__page);
> -	wait_queue_head_t *q = page_waitqueue(page);
> -	wait_on_page_bit_common(q, page, PG_locked, TASK_UNINTERRUPTIBLE,
> +	wait_queue_head_t *q = page_waitqueue(&folio->page);
> +	wait_on_page_bit_common(q, &folio->page, PG_locked, TASK_UNINTERRUPTIBLE,
>  				EXCLUSIVE);
>  }
> -EXPORT_SYMBOL(__lock_page);
> +EXPORT_SYMBOL(__folio_lock);
>  
>  int __lock_page_killable(struct page *__page)
>  {
> @@ -1661,10 +1660,10 @@ int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
>  			return 0;
>  		}
>  	} else {
> -		__lock_page(page);
> +		__folio_lock(page_folio(page));
>  	}
> -	return 1;
>  
> +	return 1;
>  }
>  
>  /**
> @@ -2835,7 +2834,9 @@ loff_t mapping_seek_hole_data(struct address_space *mapping, loff_t start,
>  static int lock_page_maybe_drop_mmap(struct vm_fault *vmf, struct page *page,
>  				     struct file **fpin)
>  {
> -	if (trylock_page(page))
> +	struct folio *folio = page_folio(page);
> +
> +	if (folio_trylock(folio))
>  		return 1;
>  
>  	/*
> @@ -2848,7 +2849,7 @@ static int lock_page_maybe_drop_mmap(struct vm_fault *vmf, struct page *page,
>  
>  	*fpin = maybe_unlock_mmap_for_io(vmf, *fpin);
>  	if (vmf->flags & FAULT_FLAG_KILLABLE) {
> -		if (__lock_page_killable(page)) {
> +		if (__lock_page_killable(&folio->page)) {
>  			/*
>  			 * We didn't have the right flags to drop the mmap_lock,
>  			 * but all fault_handlers only check for fatal signals
> @@ -2860,11 +2861,11 @@ static int lock_page_maybe_drop_mmap(struct vm_fault *vmf, struct page *page,
>  			return 0;
>  		}
>  	} else
> -		__lock_page(page);
> +		__folio_lock(folio);
> +
>  	return 1;
>  }
>  
> -
>  /*
>   * Synchronous readahead happens when we don't even find a page in the page
>   * cache at all.  We don't want to perform IO under the mmap sem, so if we have
>
diff mbox series

Patch

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 8dbba0074536..9a78397609b8 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -638,7 +638,7 @@  static inline bool wake_page_match(struct wait_page_queue *wait_page,
 	return true;
 }
 
-extern void __lock_page(struct page *page);
+void __folio_lock(struct folio *folio);
 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,
@@ -646,13 +646,24 @@  extern int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
 void unlock_page(struct page *page);
 void folio_unlock(struct folio *folio);
 
+static inline bool folio_trylock(struct folio *folio)
+{
+	return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0)));
+}
+
 /*
  * Return true if the page was successfully locked
  */
 static inline int trylock_page(struct page *page)
 {
-	page = compound_head(page);
-	return (likely(!test_and_set_bit_lock(PG_locked, &page->flags)));
+	return folio_trylock(page_folio(page));
+}
+
+static inline void folio_lock(struct folio *folio)
+{
+	might_sleep();
+	if (!folio_trylock(folio))
+		__folio_lock(folio);
 }
 
 /*
@@ -660,9 +671,12 @@  static inline int trylock_page(struct page *page)
  */
 static inline void lock_page(struct page *page)
 {
+	struct folio *folio;
 	might_sleep();
-	if (!trylock_page(page))
-		__lock_page(page);
+
+	folio = page_folio(page);
+	if (!folio_trylock(folio))
+		__folio_lock(folio);
 }
 
 /*
diff --git a/mm/filemap.c b/mm/filemap.c
index e7a6a58d6cd9..c6e5ba176764 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1187,7 +1187,7 @@  static void wake_up_page(struct page *page, int bit)
  */
 enum behavior {
 	EXCLUSIVE,	/* Hold ref to page and take the bit when woken, like
-			 * __lock_page() waiting on then setting PG_locked.
+			 * __folio_lock() waiting on then setting PG_locked.
 			 */
 	SHARED,		/* Hold ref to page and check the bit when woken, like
 			 * wait_on_page_writeback() waiting on PG_writeback.
@@ -1576,17 +1576,16 @@  void page_endio(struct page *page, bool is_write, int err)
 EXPORT_SYMBOL_GPL(page_endio);
 
 /**
- * __lock_page - get a lock on the page, assuming we need to sleep to get it
- * @__page: the page to lock
+ * __folio_lock - Get a lock on the folio, assuming we need to sleep to get it.
+ * @folio: The folio to lock
  */
-void __lock_page(struct page *__page)
+void __folio_lock(struct folio *folio)
 {
-	struct page *page = compound_head(__page);
-	wait_queue_head_t *q = page_waitqueue(page);
-	wait_on_page_bit_common(q, page, PG_locked, TASK_UNINTERRUPTIBLE,
+	wait_queue_head_t *q = page_waitqueue(&folio->page);
+	wait_on_page_bit_common(q, &folio->page, PG_locked, TASK_UNINTERRUPTIBLE,
 				EXCLUSIVE);
 }
-EXPORT_SYMBOL(__lock_page);
+EXPORT_SYMBOL(__folio_lock);
 
 int __lock_page_killable(struct page *__page)
 {
@@ -1661,10 +1660,10 @@  int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
 			return 0;
 		}
 	} else {
-		__lock_page(page);
+		__folio_lock(page_folio(page));
 	}
-	return 1;
 
+	return 1;
 }
 
 /**
@@ -2835,7 +2834,9 @@  loff_t mapping_seek_hole_data(struct address_space *mapping, loff_t start,
 static int lock_page_maybe_drop_mmap(struct vm_fault *vmf, struct page *page,
 				     struct file **fpin)
 {
-	if (trylock_page(page))
+	struct folio *folio = page_folio(page);
+
+	if (folio_trylock(folio))
 		return 1;
 
 	/*
@@ -2848,7 +2849,7 @@  static int lock_page_maybe_drop_mmap(struct vm_fault *vmf, struct page *page,
 
 	*fpin = maybe_unlock_mmap_for_io(vmf, *fpin);
 	if (vmf->flags & FAULT_FLAG_KILLABLE) {
-		if (__lock_page_killable(page)) {
+		if (__lock_page_killable(&folio->page)) {
 			/*
 			 * We didn't have the right flags to drop the mmap_lock,
 			 * but all fault_handlers only check for fatal signals
@@ -2860,11 +2861,11 @@  static int lock_page_maybe_drop_mmap(struct vm_fault *vmf, struct page *page,
 			return 0;
 		}
 	} else
-		__lock_page(page);
+		__folio_lock(folio);
+
 	return 1;
 }
 
-
 /*
  * Synchronous readahead happens when we don't even find a page in the page
  * cache at all.  We don't want to perform IO under the mmap sem, so if we have