Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753496Ab2FMA7u (ORCPT ); Tue, 12 Jun 2012 20:59:50 -0400 Received: from mga01.intel.com ([192.55.52.88]:36120 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752780Ab2FMA7t (ORCPT ); Tue, 12 Jun 2012 20:59:49 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="164885063" Date: Wed, 13 Jun 2012 08:59:46 +0800 From: Fengguang Wu To: Wanpeng Li Cc: Alexander Viro , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Gavin Shan , Jan Kara Subject: Re: [PATCH] writeback: fix hung_task alarm when sync block Message-ID: <20120613005945.GA24091@localhost> References: <1339548774-4834-1-git-send-email-liwp.linux@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1339548774-4834-1-git-send-email-liwp.linux@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2170 Lines: 64 On Wed, Jun 13, 2012 at 08:52:53AM +0800, Wanpeng Li wrote: > From: Wanpeng Li > > I use several dd processes to write a slow SD card > dd if=/dev/sda1 of=/dev/sdc4 bs=1M count=4000 > and several sync commands(maybe > 10),dmesg show this: > > [ 366.888741] INFO: task sync:3518 blocked for more than 120 seconds. > [ 366.888742] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [ 366.888746] sync D 00000201 0 3518 3462 0x00000000 > Too many similar messages flood the logs. So I use a present method to > fix this issue. > ------------------------------------------ > Author: Mark Lord > Date: Fri Sep 24 09:51:13 2010 -0400 > > block: Prevent hang_check firing during long I/O > ------------------------------------------ > > Signed-off-by: Wanpeng Li Yeah that's also what I'd like to do. So you've tested it? > --- > fs/fs-writeback.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c > index f2d0109..5d403a1 100644 > --- a/fs/fs-writeback.c > +++ b/fs/fs-writeback.c > @@ -1300,6 +1300,7 @@ void writeback_inodes_sb_nr(struct super_block *sb, > enum wb_reason reason) > { > DECLARE_COMPLETION_ONSTACK(done); > + unsigned long hangcheck; > struct wb_writeback_work work = { > .sb = sb, > .sync_mode = WB_SYNC_NONE, > @@ -1311,7 +1312,12 @@ void writeback_inodes_sb_nr(struct super_block *sb, > > WARN_ON(!rwsem_is_locked(&sb->s_umount)); > bdi_queue_work(sb->s_bdi, &work); > - wait_for_completion(&done); > + hangcheck = sysctl_hung_task_timeout_secs; > + if (hangcheck) The hangcheck variable looks redundant. > + while (!wait_for_completion_timeout(&done, HZ/2)) > + ; > + else > + wait_for_completion(&done); > } > EXPORT_SYMBOL(writeback_inodes_sb_nr); > > -- > 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/