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From: David Woodhouse <dwmw2@infradead.org>
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To: Linus Torvalds <torvalds@transmeta.com>
Cc: davidm@hpl.hp.com, Alan Cox <alan@lxorguk.ukuu.org.uk>,
       linux-kernel@vger.kernel.org, davidm@napali.hpl.hp.com
Subject: Re: adjust prefetch in free_one_pgd() 
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Date: Sat, 03 Aug 2002 17:59:49 +0100
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torvalds@transmeta.com said:
> > I thought the prefetches API intended this to be a safe operation?
> Well, any _sane_ prefetch API would be safe.
> However, there is known-broken hardware out there, in which a prefetch
> from IO space will kill the machine. 

If you prefetch off the end of your object, and the thing you end up 
prefetching is a DMA buffer which we'd just nuked from our cache to allow 
the device to DMA into it, something's going to be unhappy regardless of 
whether your prefetch faults or not.

--
dwmw2


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