[PATCH v2 29/46] mm/writeback: Add folio_account_cleaned()

["Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>]

Get the statistics right; compound pages were being accounted as a
single page.  Also move the declaration to filemap.h since this is
part of the page cache.  Add a wrapper for account_page_cleaned().

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
 include/linux/mm.h      |  3 ---
 include/linux/pagemap.h |  7 +++++++
 mm/page-writeback.c     | 11 ++++++-----
 3 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 3c8dfcb56fa5..2ccf294afc3e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -39,7 +39,6 @@ struct anon_vma_chain;
 struct file_ra_state;
 struct user_struct;
 struct writeback_control;
-struct bdi_writeback;
 struct pt_regs;
 
 extern int sysctl_page_lock_unfairness;
@@ -1986,8 +1985,6 @@ extern void do_invalidatepage(struct page *page, unsigned int offset,
 
 int redirty_page_for_writepage(struct writeback_control *wbc,
 				struct page *page);
-void account_page_cleaned(struct page *page, struct address_space *mapping,
-			  struct bdi_writeback *wb);
 bool folio_mark_dirty(struct folio *folio);
 bool set_page_dirty(struct page *page);
 int set_page_dirty_lock(struct page *page);
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index e6a9756293aa..084fca551e60 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -778,6 +778,13 @@ static inline void __set_page_dirty(struct page *page,
 {
 	__folio_mark_dirty((struct folio *)page, mapping, warn);
 }
+void folio_account_cleaned(struct folio *folio, struct address_space *mapping,
+			  struct bdi_writeback *wb);
+static inline void account_page_cleaned(struct page *page,
+		struct address_space *mapping, struct bdi_writeback *wb)
+{
+	return folio_account_cleaned(page_folio(page), mapping, wb);
+}
 
 int __set_page_dirty_nobuffers(struct page *page);
 int __set_page_dirty_no_writeback(struct page *page);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 64b989eff9f5..cf48ac5b85f6 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2449,14 +2449,15 @@ static void folio_account_dirtied(struct folio *folio,
  *
  * Caller must hold lock_page_memcg().
  */
-void account_page_cleaned(struct page *page, struct address_space *mapping,
+void folio_account_cleaned(struct folio *folio, struct address_space *mapping,
 			  struct bdi_writeback *wb)
 {
 	if (mapping_can_writeback(mapping)) {
-		dec_lruvec_page_state(page, NR_FILE_DIRTY);
-		dec_zone_page_state(page, NR_ZONE_WRITE_PENDING);
-		dec_wb_stat(wb, WB_RECLAIMABLE);
-		task_io_account_cancelled_write(PAGE_SIZE);
+		long nr = folio_nr_pages(folio);
+		lruvec_stat_mod_folio(folio, NR_FILE_DIRTY, -nr);
+		zone_stat_mod_folio(folio, NR_ZONE_WRITE_PENDING, -nr);
+		wb_stat_mod(wb, WB_RECLAIMABLE, -nr);
+		task_io_account_cancelled_write(folio_size(folio));
 	}
 }
 
-- 
2.30.2