From mboxrd@z Thu Jan  1 00:00:00 1970
From: Fengguang Wu <fengguang.wu@intel.com>
Subject: Re: [PATCH] writeback: fix hung_task alarm when sync block
Date: Wed, 13 Jun 2012 09:18:17 +0800
Message-ID: <20120613011817.GA24315@localhost>
References: <1339548774-4834-1-git-send-email-liwp.linux@gmail.com>
 <20120613005945.GA24091@localhost>
 <20120613011151.GA2181@kernel>
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Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	Gavin Shan <shangw@linux.vnet.ibm.com>
To: Wanpeng Li <liwp.linux@gmail.com>
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In-Reply-To: <20120613011151.GA2181@kernel>
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List-Id: linux-fsdevel.vger.kernel.org

> >> @@ -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.
> 
> if sysctl_hung_task_timeout_secs is equal to ZERO, it means infinite
> timeout -- no checking done. So I think wait_for_completion_timeout 
> makes no sense this time.

I mean, you can test sysctl_hung_task_timeout_secs directly?
It's a one shot test anyway.

> >> +		while (!wait_for_completion_timeout(&done, HZ/2))
> >> +			;
> >> +	else
> >> +		wait_for_completion(&done);
> >>  }
> >>  EXPORT_SYMBOL(writeback_inodes_sb_nr);
> >>  
> >> -- 
> >> 1.7.9.5