linux-kernel - [PATCH 1/2] mm: vmscan: remove folio_test

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Message-ID: <b8c0fe71982aa1cafafd59d8e71064efaac16007.1757648598.git.baolin.wang@linux.alibaba.com>
Date: Fri, 12 Sep 2025 11:45:07 +0800
From: Baolin Wang <baolin.wang@...ux.alibaba.com>
To: akpm@...ux-foundation.org,
	hannes@...xchg.org
Cc: david@...hat.com,
	mhocko@...nel.org,
	zhengqi.arch@...edance.com,
	shakeel.butt@...ux.dev,
	lorenzo.stoakes@...cle.com,
	hughd@...gle.com,
	willy@...radead.org,
	baolin.wang@...ux.alibaba.com,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] mm: vmscan: remove folio_test_private() check in pageout()

Currently, we no longer attempt to write back filesystem folios in pageout(),
and only tmpfs/shmem folios and anonymous swapcache folios can be written back.
Moreover, tmpfs/shmem and swapcache folios do not use the PG_private flag,
which means no fs-private private data is used. Therefore, we can remove the
redundant folio_test_private() checks and related buffer_head release logic.

Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
---
 mm/vmscan.c | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index f1fc36729ddd..8056fccb9cc4 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -697,22 +697,8 @@ static pageout_t pageout(struct folio *folio, struct address_space *mapping,
 	 * swap_backing_dev_info is bust: it doesn't reflect the
 	 * congestion state of the swapdevs.  Easy to fix, if needed.
 	 */
-	if (!is_page_cache_freeable(folio))
+	if (!is_page_cache_freeable(folio) || !mapping)
 		return PAGE_KEEP;
-	if (!mapping) {
-		/*
-		 * Some data journaling orphaned folios can have
-		 * folio->mapping == NULL while being dirty with clean buffers.
-		 */
-		if (folio_test_private(folio)) {
-			if (try_to_free_buffers(folio)) {
-				folio_clear_dirty(folio);
-				pr_info("%s: orphaned folio\n", __func__);
-				return PAGE_CLEAN;
-			}
-		}
-		return PAGE_KEEP;
-	}
 
 	if (!shmem_mapping(mapping) && !folio_test_anon(folio))
 		return PAGE_ACTIVATE;
-- 
2.43.7