From nobody Mon Feb 9 05:43:09 2026 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 0AEB639525C; Tue, 3 Feb 2026 09:40:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.242.206.163 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770111643; cv=none; b=GaTXxZQJcjcJs9mPGLIk0tzcuC8WqPRxvmljwpoekEEoECZ2craS+VVJcZ3qiVB8Fv+piJXpR+BOanSWvNN9GBCjMnQtjvyjBt6Pk9bvX716LRsEb76HkDBpxWH97JUzbaDRyZqlRKkyDMTInXRUmI+0LCS/u2y1WyzQKjGd53Y= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770111643; c=relaxed/simple; bh=fi2zIziiiMfPuCFFCVLn3/jmCEGQIeLj3zxopoPQsAU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=JdHYq1iRUYoLDsjQdsx93Jjcd2hvu+zHVVFtA9K4wjnzBUBhPJGpXnObnpXAdCneTFvIjUhto8g9EWm1J8g3v2lKSCnOZLnUC0fq9McxYh8XNaRaO88Vg3a/c5FBaHjGkIItLnNSbzjRmvARUUO9vtWid77TPl8+0cNEtNoEyUg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn; spf=pass smtp.mailfrom=loongson.cn; arc=none smtp.client-ip=114.242.206.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=loongson.cn Received: from loongson.cn (unknown [223.64.69.42]) by gateway (Coremail) with SMTP id _____8DxusKPwoFpEFEPAA--.49206S3; Tue, 03 Feb 2026 17:40:31 +0800 (CST) Received: from localhost.localdomain (unknown [223.64.69.42]) by front1 (Coremail) with SMTP id qMiowJBx58CHwoFpPAY_AA--.22892S2; Tue, 03 Feb 2026 17:40:30 +0800 (CST) From: Huacai Chen To: Huacai Chen , Alexander Viro , Christian Brauner Cc: Jan Kara , linux-fsdevel@vger.kernel.org, Xuefeng Li , Julian Sun , linux-kernel@vger.kernel.org, Huacai Chen Subject: [PATCH V3] writeback: Fix wakeup and logging timeouts for !DETECT_HUNG_TASK Date: Tue, 3 Feb 2026 17:40:14 +0800 Message-ID: <20260203094014.2273240-1-chenhuacai@loongson.cn> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: qMiowJBx58CHwoFpPAY_AA--.22892S2 X-CM-SenderInfo: hfkh0x5xdftxo6or00hjvr0hdfq/ X-Coremail-Antispam: 1Uk129KBj93XoWxWw1UGFyrJFyfAFWxurWrCrX_yoW5WryrpF Wrtwn0ya1vya43Kr1ku3ZrWFyFk3ykCrZ7WwnrGFW0vwn5XFZ5tFW7K34UtF13JFZ3ZFyS vFWvyrWxGF1jqagCm3ZEXasCq-sJn29KB7ZKAUJUUUU5529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUk2b4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Gr0_Xr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AK xVW8Jr0_Cr1UM2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6xkI12xvs2x26I8E6xACxx 1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1Y6r17McIj6I8E87Iv 67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41l42xK82IYc2 Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s02 6x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0x vE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r4UMIIF0xvE 42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87Iv6x kF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxUcVc_UUUUU Content-Type: text/plain; charset="utf-8" Recent changes of fs-writeback cause such warnings if DETECT_HUNG_TASK is not enabled: INFO: The task sync:1342 has been waiting for writeback completion for more= than 1 seconds. The reason is sysctl_hung_task_timeout_secs is 0 when DETECT_HUNG_TASK is not enabled, then it causes the warning message even if the writeback lasts for only one second. Guard the wakeup and logging with "#ifdef CONFIG_DETECT_HUNG_TASK" can eliminate the warning messages. But on the other hand, it is possible that sysctl_hung_task_timeout_secs be also 0 when DETECT_HUNG_TASK is enabled. So let's just check the value of sysctl_hung_task_timeout_secs to decide whether do wakeup and logging. Fixes: 1888635532fb ("writeback: Wake up waiting tasks when finishing the w= riteback of a chunk.") Fixes: d6e621590764 ("writeback: Add logging for slow writeback (exceeds sy= sctl_hung_task_timeout_secs)") Signed-off-by: Huacai Chen Reviewed-by: Jan Kara Reviewed-by: Pankaj Raghav --- V2: Disable wakeup and logging for !DETECT_HUNG_TASK. V3: Also handle the case for DETECT_HUNG_TASK if sysctl_hung_task_timeout_s= ecs is 0. fs/fs-writeback.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 5444fc706ac7..79b02ac66ac6 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -198,10 +198,11 @@ static void wb_queue_work(struct bdi_writeback *wb, =20 static bool wb_wait_for_completion_cb(struct wb_completion *done) { + unsigned long timeout =3D sysctl_hung_task_timeout_secs; unsigned long waited_secs =3D (jiffies - done->wait_start) / HZ; =20 done->progress_stamp =3D jiffies; - if (waited_secs > sysctl_hung_task_timeout_secs) + if (timeout && (waited_secs > timeout)) pr_info("INFO: The task %s:%d has been waiting for writeback " "completion for more than %lu seconds.", current->comm, current->pid, waited_secs); @@ -1944,6 +1945,7 @@ static long writeback_sb_inodes(struct super_block *s= b, .range_end =3D LLONG_MAX, }; unsigned long start_time =3D jiffies; + unsigned long timeout =3D sysctl_hung_task_timeout_secs; long write_chunk; long total_wrote =3D 0; /* count both pages and inodes */ unsigned long dirtied_before =3D jiffies; @@ -2030,9 +2032,8 @@ static long writeback_sb_inodes(struct super_block *s= b, __writeback_single_inode(inode, &wbc); =20 /* Report progress to inform the hung task detector of the progress. */ - if (work->done && work->done->progress_stamp && - (jiffies - work->done->progress_stamp) > HZ * - sysctl_hung_task_timeout_secs / 2) + if (work->done && work->done->progress_stamp && timeout && + (jiffies - work->done->progress_stamp) > HZ * timeout / 2) wake_up_all(work->done->waitq); =20 wbc_detach_inode(&wbc); --=20 2.47.3