Re: [feature] automatically detect hung TASK_UNINTERRUPTIBLE tasks

[Mark Lord <lkml@rtr.ca>]

Arjan van de Ven wrote:
> 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.
..

Mmm.. but the SCSI layer may do many retries, each with 30sec timeouts..
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