From: arjan@fenrus.demon.nl
To: alan@lxorguk.ukuu.org.uk (Alan Cox)
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH]: Fix MTRR handling on HT CPUs (improved)
Date: Fri, 25 Jan 2002 18:51:24 +0000 (GMT) [thread overview]
Message-ID: <m16UBRc-000OVeC@amadeus.home.nl> (raw)
In-Reply-To: <E16UBUl-0003J9-00@the-village.bc.nu>
In article <E16UBUl-0003J9-00@the-village.bc.nu> you wrote:
> As Dave pointed out I was mixing them
>> just not do it on the right CPU (you're _not_ supposed to read to see if
>> you are writing the same value: MTRR's can at least in theory have
>> side-effects, so it's not the same check as for the microcode update).
> So why not just set it twice - surely that is harmless ? Why add complex
> code ?
mtrr code does
"read value" -> store in variable
"set uncached"
<do lots of fiddling>
"write stored value"
on all cpus precisely in parallel.
Now... on HT the second half will store the value the first half just set to
uncached. and worse: it will RESTORE that into the final mtrr..
next prev parent reply other threads:[~2002-01-25 18:52 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-24 20:57 [PATCH]: Fix MTRR handling on HT CPUs (improved) Martin Wilck
2002-01-24 21:39 ` Linus Torvalds
2002-01-24 22:30 ` Dave Jones
2002-01-25 9:37 ` Martin Wilck
2002-01-25 11:05 ` Martin Wilck
2002-01-25 18:08 ` Alan Cox
2002-01-25 18:19 ` Dave Jones
2002-01-25 18:20 ` Alan Cox
2002-01-25 18:14 ` Linus Torvalds
2002-01-25 18:54 ` Alan Cox
2002-01-25 18:51 ` arjan [this message]
2002-01-25 18:57 ` Dave Jones
2002-01-25 20:40 ` Linus Torvalds
2002-01-28 8:13 ` Martin Wilck
2002-02-13 11:42 ` SMT, again (was: Re: [PATCH]: Fix MTRR handling on HT CPUs) Martin Wilck
2002-02-13 12:15 ` Alan Cox
2002-01-25 21:30 ` [PATCH]: Fix MTRR handling on HT CPUs (improved) Timothy Covell
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