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From: Kefeng Wang <wangkefeng.wang@huawei.com>
To: <brauner@kernel.org>, <djwong@kernel.org>, <cem@kernel.org>,
	<akpm@linux-foundation.org>, <vbabka@kernel.org>,
	<surenb@google.com>, <mhocko@suse.com>,
	<brendan.jackman@linux.dev>, <hannes@cmpxchg.org>,
	<ziy@nvidia.com>, <david@kernel.org>, <qi.zheng@linux.dev>,
	<shakeel.butt@linux.dev>, <ljs@kernel.org>
Cc: <linux-xfs@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>,
	<linux-mm@kvack.org>, Kefeng Wang <wangkefeng.wang@huawei.com>
Subject: [PATCH 2/4] iomap: simplify writepages reclaim guard
Date: Wed, 2 Sep 2026 21:16:51 +0800	[thread overview]
Message-ID: <20260902131653.1338227-3-wangkefeng.wang@huawei.com> (raw)
In-Reply-To: <20260902131653.1338227-1-wangkefeng.wang@huawei.com>

Now that kswapd can no longer reach filesystem writeback (pageout()
returns PAGE_ACTIVATE for non-shmem, non-anon folios), any PF_MEMALLOC
context in iomap_writepages() indicates a VM regression, simplify
the check by removing PF_KSWAPD.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 fs/iomap/buffered-io.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 0a5ebfda90f1..6306ca747f3b 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -2077,8 +2077,7 @@ iomap_writepages(struct iomap_writepage_ctx *wpc)
 	 * Writeback from reclaim context should never happen except in the case
 	 * of a VM regression so warn about it and refuse to write the data.
 	 */
-	if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC | PF_KSWAPD)) ==
-			PF_MEMALLOC))
+	if (WARN_ON_ONCE((current->flags & PF_MEMALLOC)))
 		return -EIO;
 
 	while ((folio = writeback_iter(mapping, wpc->wbc, folio, &error))) {
-- 
2.55.0


  parent reply	other threads:[~2026-09-02 13:17 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-02 13:16 [PATCH 0/4] mm: replace PF_KCOMPACTD/PF_KSWAPD with kthread_func() Kefeng Wang
2026-09-02 13:16 ` [PATCH 1/4] xfs: remove dead kswapd flag inheritance from btree split worker Kefeng Wang
2026-09-02 14:32   ` Christoph Hellwig
2026-09-02 15:33   ` Shakeel Butt
2026-09-02 13:16 ` Kefeng Wang [this message]
2026-09-02 14:32   ` [PATCH 2/4] iomap: simplify writepages reclaim guard Christoph Hellwig
2026-09-03 13:46     ` Kefeng Wang
2026-09-02 15:34   ` Shakeel Butt
2026-09-02 13:16 ` [PATCH 3/4] mm: replace PF_KSWAPD flag with kthread_func() check Kefeng Wang
2026-09-02 15:36   ` Shakeel Butt
2026-09-02 16:35   ` Vlastimil Babka (SUSE)
2026-09-02 16:39   ` Zi Yan
2026-09-10 11:56   ` David Hildenbrand (Arm)
2026-09-02 13:16 ` [PATCH 4/4] mm: replace PF_KCOMPACTD " Kefeng Wang
2026-09-02 15:37   ` Shakeel Butt
2026-09-02 16:36   ` Vlastimil Babka (SUSE)
2026-09-02 16:40   ` Zi Yan
2026-09-10 11:57   ` David Hildenbrand (Arm)
2026-09-02 15:31 ` [PATCH 0/4] mm: replace PF_KCOMPACTD/PF_KSWAPD with kthread_func() Shakeel Butt
2026-09-02 20:44 ` Andrew Morton
2026-09-03 13:37   ` [PATCH] xfs: fix NOFS state corruption in btree split worker Kefeng Wang
2026-09-03 13:52     ` Brian Foster
2026-09-04  0:41       ` Kefeng Wang
2026-09-04 11:57         ` Brian Foster
2026-09-10  5:47     ` Christoph Hellwig
2026-09-10  6:07       ` Darrick J. Wong
2026-09-15  7:09       ` Zhou, Yun
2026-09-15  9:19         ` Carlos Maiolino
2026-09-15 10:34           ` Zhou, Yun
2026-09-15 10:50             ` Carlos Maiolino
     [not found]     ` <20260910140742.833170-1-wangkefeng.wang@huawei.com>
     [not found]       ` <aqLqeTsbKBMEsl-G@bfoster>
2026-09-11  0:57         ` [PATCH] xfs: kill xfs_trans_set/clear_context() helpers Kefeng Wang
2026-09-11  7:12           ` Christoph Hellwig
2026-09-11 10:51             ` Kefeng Wang
2026-09-03 13:40   ` [PATCH 0/4] mm: replace PF_KCOMPACTD/PF_KSWAPD with kthread_func() Kefeng Wang

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