From: Heiko Carstens <heiko.carstens@de.ibm.com>
To: Dave Hansen <haveblue@us.ibm.com>
Cc: linux-mm <linux-mm@kvack.org>, Bob Picco <bob.picco@hp.com>
Subject: Re: sparsemem & sparsemem extreme question
Date: Thu, 6 Oct 2005 09:39:43 +0200 [thread overview]
Message-ID: <20051006073943.GA2482@osiris.boeblingen.de.ibm.com> (raw)
In-Reply-To: <1128550002.18249.14.camel@localhost>
> > As already mentioned, we will have physical memory with the MSB set. Afaik
> > the hardware uses this bit to distinguish between different types of memory.
> > So we are going to have the full 64 bit address space.
> Is it just the MSB? If so, we can probably just shift it down to some
> reasonable address. The only issue comes if you really have the whole
> address space used in some random way.
Unfortunately there is more than just the MSB. If the MSB is set then there
will be a 'model dependent' number of bits just below the MSB used to encode
whatever the hardware thinks is necessary. Also you cannot tell how these
bits will be set from an operating system's view. Best thing to do is to
assume nothing and leave the addresses alone.
Heiko
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prev parent reply other threads:[~2005-10-06 7:40 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-04 6:50 Heiko Carstens
2005-10-04 14:33 ` Andy Whitcroft
2005-10-04 16:15 ` Dave Hansen
2005-10-05 6:39 ` Heiko Carstens
2005-10-05 15:52 ` Dave Hansen
2005-10-05 15:58 ` Heiko Carstens
2005-10-05 16:05 ` Dave Hansen
2005-10-05 16:10 ` Heiko Carstens
2005-10-05 16:20 ` Dave Hansen
2005-10-05 17:12 ` Heiko Carstens
2005-10-05 17:20 ` Dave Hansen
2005-10-05 17:45 ` Heiko Carstens
2005-10-05 17:57 ` Dave Hansen
2005-10-05 18:04 ` Heiko Carstens
2005-10-05 18:42 ` Bob Picco
2005-10-05 22:06 ` Dave Hansen
2005-10-06 7:39 ` Heiko Carstens [this message]
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