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Date: Wed, 26 Sep 2007 07:57:10 -0400
From: Ric Wheeler <ric@emc.com>
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To: Nick Piggin <nickpiggin@yahoo.com.au>,
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CC: Bob Bell <b_lkml@thebellsplace.com>, Matthew Wilcox <matthew@wil.cx>,
       trond@netapp.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] TASK_KILLABLE version 2
References: <20070924201648.GA6850@newbie.thebellsplace.net>
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Bob Bell wrote:
> On Sat, Sep 01, 2007 at 08:43:49PM -0600, Matthew Wilcox wrote:
>> Here's the second version of TASK_KILLABLE.  A few changes since 
>> version 1:
> <snip>
>> I obviously haven't covered every place that can result in a process
>> sleeping uninterruptibly while attempting an operation.  But sync_page
>> (patch 4/5) covers about 90% of the times I've attempted to kill cat,
>> and I hope that by providing the two examples, I can help other people
>> to fix the cases that they find interesting.
> 
> I've been testing this patch on my systems.  It's working for me when
> I read() a file.  Asynchronous write()s seem okay, too.  However,
> synchronous writes (caused by either calling fsync() or fcntl() to
> release a lock) prevent the process from being killed when the NFS
> server goes down.

After hearing again last month about how few people actually read every 
lkml thread, I  wanted to point you all at this thread explicitly since 
it seems that we are getting somewhat close to having a forced unmount 
that actually is usable by real applications, something that we seem to 
have been talking about for many years ;-)

With Matthew's original TASK_KILLABLE patch, we have a solution for a 
task read, but still have some holes (fsync & fcntl, others?) that need 
fixed as well for NFS clients.

Is this patch going in the right direction?

ric



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