Date: Mon, 3 Dec 2007 07:23:28 -0800
From: Arjan van de Ven <arjan@infradead.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: Radoslaw Szkodzinski <lkml@astralstorm.puszkin.org>,
       Andi Kleen <andi@firstfloor.org>, Ingo Molnar <mingo@elte.hu>,
       linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
       Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [feature] automatically detect hung TASK_UNINTERRUPTIBLE tasks
Message-ID: <20071203072328.371d0b00@laptopd505.fenrus.org>
In-Reply-To: <20071203102715.GC28560@one.firstfloor.org>
References: <20071202185945.GA25990@elte.hu>
	<20071202114152.3bf4332d@laptopd505.fenrus.org>
	<20071202200953.GA23994@one.firstfloor.org>
	<20071202202602.GA16480@elte.hu>
	<20071202204725.GA25891@one.firstfloor.org>
	<20071202144331.6abf1289@laptopd505.fenrus.org>
	<20071203000741.GB26636@one.firstfloor.org>
	<20071202165913.3eaebee6@laptopd505.fenrus.org>
	<20071203095501.GB28560@one.firstfloor.org>
	<20071203111520.33ed2139@astralstorm.puszkin.org>
	<20071203102715.GC28560@one.firstfloor.org>
Organization: Intel
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On Mon, 3 Dec 2007 11:27:15 +0100
Andi Kleen <andi@firstfloor.org> wrote:

> > Kernel waiting 2 minutes on TASK_UNINTERRUPTIBLE is certainly
> > broken.
> 
> What should it do when the NFS server doesn't answer anymore or 
> when the network to the SAN RAID array located a few hundred KM away
> develops some hickup?  Or just the SCSI driver decides to do lengthy
> error recovery  -- you could argue that is broken if it takes longer 
> than 2 minutes, but in practice these things are hard to test
> and to fix.
> 

the scsi layer will have the IO totally aborted within that time anyway;
the retry timeout for disks is 30 seconds after all.


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