From: David Woodhouse <dwmw2@infradead.org>
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()
Date: Sat, 03 Aug 2002 17:59:49 +0100 [thread overview]
Message-ID: <17304.1028393989@redhat.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0208020844000.18265-100000@home.transmeta.com>
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
next prev parent reply other threads:[~2002-08-03 16:56 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-08-02 0:12 David Mosberger
2002-08-02 13:04 ` Alan Cox
2002-08-02 15:39 ` David Mosberger
2002-08-02 15:46 ` Linus Torvalds
2002-08-02 15:56 ` Dave Jones
2002-08-02 15:59 ` Linus Torvalds
2002-08-02 16:04 ` Dave Jones
2002-08-02 17:49 ` Alan Cox
2002-08-02 16:38 ` David Mosberger
2002-08-02 17:58 ` Alan Cox
2002-08-02 16:53 ` David Mosberger
2002-08-03 16:59 ` David Woodhouse [this message]
2002-08-03 17:22 ` Linus Torvalds
2002-08-03 17:39 ` David Woodhouse
2002-08-03 19:36 ` Linus Torvalds
2002-08-03 22:03 ` David Woodhouse
2002-08-03 22:40 ` Linus Torvalds
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