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Date: Sat, 11 Jun 2005 17:16:46 +0200
From: Andrea Arcangeli <andrea@suse.de>
To: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Bill Huey <bhuey@lnxw.com>, Lee Revell <rlrevell@joe-job.com>,
       Tim Bird <tim.bird@am.sony.com>, linux-kernel@vger.kernel.org,
       tglx@linutronix.de, karim@opersys.com, mingo@elte.hu,
       pmarques@grupopie.com, bruce@andrew.cmu.edu, nickpiggin@yahoo.com.au,
       ak@muc.de, sdietrich@mvista.com, dwalker@mvista.com, hch@infradead.org,
       akpm@osdl.org
Subject: Re: Attempted summary of "RT patch acceptance" thread
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On Fri, Jun 10, 2005 at 06:07:55PM -0700, Paul E. McKenney wrote:
> 	f.	Any code that manipulates hardware that can stall the
> 		bus, delay interrupts, or otherwise interfere with
> 		forward progress.  Note that it is also necessary to
> 		inspect user-level code that directly manipulates such
> 		hardware.
> 
> I added point "f".  Does that cover it?

Yes. F is really a bad problem if it really can cause DMA starvation on
the memory bus on some arch as stated on this thread. Hopefully
measurements are good enough to rule it out and there will be no corner
cases triggering once in a while.