[PATCH 10/25] mm/filemap: Convert end_page_writeback to use a folio

[Matthew Wilcox (Oracle)]

With my config, this function shrinks from 480 bytes to 240 bytes
due to elimination of repeated calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org>
---
 mm/filemap.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 6012e8a7bd6c..654bba53442a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1148,11 +1148,11 @@ static void wake_up_page_bit(struct page *page, int 
bit_nr)
        spin_unlock_irqrestore(&q->lock, flags);
 }
 
-static void wake_up_page(struct page *page, int bit)
+static void wake_up_folio(struct folio *folio, int bit)
 {
-       if (!PageWaiters(page))
+       if (!FolioWaiters(folio))
                return;
-       wake_up_page_bit(page, bit);
+       wake_up_page_bit(&folio->page, bit);
 }
 
 /*
@@ -1466,6 +1466,8 @@ EXPORT_SYMBOL(unlock_folio);
  */
 void end_page_writeback(struct page *page)
 {
+       struct folio *folio = page_folio(page);
+
        /*
         * TestClearPageReclaim could be used here but it is an atomic
         * operation and overkill in this particular case. Failing to
@@ -1473,9 +1475,9 @@ void end_page_writeback(struct page *page)
         * justify taking an atomic operation penalty at the end of
         * ever page writeback.
         */
-       if (PageReclaim(page)) {
-               ClearPageReclaim(page);
-               rotate_reclaimable_page(page);
+       if (FolioReclaim(folio)) {
+               ClearFolioReclaim(folio);
+               rotate_reclaimable_page(&folio->page);
        }
 
        /*
@@ -1484,13 +1486,13 @@ void end_page_writeback(struct page *page)
         * But here we must make sure that the page is not freed and
         * reused before the wake_up_page().
         */
-       get_page(page);
-       if (!test_clear_page_writeback(page))
+       get_folio(folio);
+       if (!test_clear_page_writeback(&folio->page))
                BUG();
 
        smp_mb__after_atomic();
-       wake_up_page(page, PG_writeback);
-       put_page(page);
+       wake_up_folio(folio, PG_writeback);
+       put_folio(folio);
 }
 EXPORT_SYMBOL(end_page_writeback);
 
-- 
2.29.2