Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: Opteron box and 4Gb memory | Date | Fri, 26 Oct 2007 00:45:43 +0200 |
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On Thursday, 25 October 2007 23:58, H. Peter Anvin wrote: > J.A. Magallon wrote: > > Hi... > > > > I have some Quad-Opteron boxes with 4Gb memory and two of them are > > running two different Linux distros. > > > > Box one sees 4Gb of memory, but box two just sees 3. > > Their mtrr setups are different: > > > > Why ? Is it a bios setup problem ? A kernel problem ? > > grep HIGHMEN in configs for both kernels does not give anything, so > > I still understand less this thing... > > > > It would depend on how the BIOS programmed the memory controllers. For > 32-bit (and lots of device) compatibility, a memory hole is required > below 4 GB. Not all memory controllers can remap memory in the 3-4 GB > range above the 4 GB memory; I'm not sure if that varies with the > different Opteron processors.
It shouldn't, AFAICS.
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