Messages in this thread | | | From | Prakash Punnoor <> | Subject | Re: AMD64, 4GB, mttr questions | Date | Thu, 26 Jan 2006 08:37:41 +0100 |
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Am Mittwoch Januar 25 2006 01:13 schrieb Robert Hancock: > Prakash Punnoor wrote: > > I have a machine with 4GB RAM, an Athlon64 X2 and following mttr entries: > > > > reg00: base=0x00000000 ( 0MB), size=4096MB: write-back, count=1 > > reg01: base=0x100000000 (4096MB), size=2048MB: write-back, count=1 > > reg02: base=0x80000000 (2048MB), size=2048MB: uncachable, count=1 > > > > First of all, why is there an uncachable region? Is it the upper half of > > memory? Or is this just a hole and the remaining 2GB are seated at > > 0x100000000 ? > > Your e820 memory map shows the first 2GB of RAM is at 0-2GB and the > remaining 2GB is at 4-6GB, so yes there is a hole. This doesn't explain > why all of 0-4GB is set as write-back and then the top half of it is > also set as uncacheable. This will presumably have been set up by the > BIOS though, I don't think the kernel does this.
OK thanks to both of you for clearing this up. :-)
Cheers, -- (°= =°) //\ Prakash Punnoor /\\ V_/ \_V [unhandled content-type:application/pgp-signature] | |