From: Andi Kleen <andi@firstfloor.org>
To: Zhao Forrest <forrest.zhao@gmail.com>
Cc: discuss@x86-64.org, linux-kernel@vger.kernel.org
Subject: Re: [discuss] A question about GART aperture unmap
Date: Thu, 10 May 2007 11:49:08 +0200 [thread overview]
Message-ID: <20070510094908.GB14898@one.firstfloor.org> (raw)
In-Reply-To: <ac8af0be0705092259p65f057bcoe5e1b9abb963d5e3@mail.gmail.com>
> After commenting out clear_kernel_mapping() line, the system would
> have sync flood and reset from time to time. However when with this
> clear_kernel_mapping() line, no system reset happened.
Hmm, that should not happen. Normally the problems fixed by
this are expected to be very rare and you also should not get
sync flood, but just cache line corruption. While it might be possible
for random corruption to then cause sync flood that should be again
rather unlikely. If it's repeatable quickly something else
must be wrong.
>
> As we know that CPU prefetch never cross the page boundary, in this
That only applies to sequential prefetch. But speculative execution can
prefetch pretty much any address. That is why the clear_kernel_mapping is
needed.
-Andi
next prev parent reply other threads:[~2007-05-10 9:49 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-10 5:59 A question about GART aperture unmap Zhao Forrest
2007-05-10 9:49 ` Andi Kleen [this message]
2007-05-10 10:00 ` [discuss] " Zhao Forrest
2007-05-10 10:09 ` Zhao Forrest
2007-05-10 10:14 ` Zhao Forrest
2007-05-10 11:06 ` Andi Kleen
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