F7 64bit 4G Memory
srikanth.konjarla at gmail.com
Tue Jul 3 11:40:43 UTC 2007
Thanks for the links. First, i think PAE is for 32 bit kernel and
second, it is needed if you have more than 4G (>4G). My machine does not
fall under any category.
Marcelo de Souza Sant'Anna wrote:
> Read this too:
> On Mon, 2007-07-02 at 22:37 -0400, Srikanth Konjarla wrote:
>> Thanks for the response. Interestingly, i could not find any BIOS
>> options pertaining to memory.
>> I found the following.
>> # cat /proc/mtrr
>> reg00: base=0xfeda0000 (4077MB), size= 128KB: write-back, count=1
>> reg01: base=0xfff00000 (4095MB), size= 1MB: write-protect, count=1
>> reg02: base=0x00000000 ( 0MB), size=2048MB: write-back, count=1
>> reg03: base=0x80000000 (2048MB), size=1024MB: write-back, count=1
>> reg04: base=0xc0000000 (3072MB), size= 256MB: write-back, count=1
>> Could be incompatible memory modules or something?
>> Wolfgang S. Rupprecht wrote:
>> > Srikanth Konjarla <srikanth.konjarla at gmail.com <mailto:srikanth.konjarla at gmail.com>> writes:
>> >> I am running F7 in 64-bit mode on a laptop. I have upgraded the memory
>> >> from 3G to 4G (Bios confirms it) but kernel sees only 3.2G (i have
>> >> passed mem=4096M kernel parameter). Wondering if i am missing anything
>> >> here.
>> > What you are missing is the really nasty design of IBM-PC legacy
>> > memory allocations. ;-)
>> > Play around in your BIOS and see if you can map the excess memory
>> > above 4GB. Often the labels for the settings will have the term
>> > "MTRR" in the name. When you get it right "cat /proc/mtrr" should
>> > show the extra 750MBytes mapped above 4 Gigs. The setting names might
>> > not make much sense (at least they don't on my Tyan). You might need
>> > to just try them all and see what effect they have on the linux mttr
>> > settings. Here is what it looks like on my board when I have it set
>> > to see all 4 GBytes:
>> > $ cat /proc/mtrr
>> > reg00: base=0x00000000 ( 0MB), size=2048MB: write-back, count=1
>> > reg01: base=0x80000000 (2048MB), size=1024MB: write-back, count=1
>> > reg02: base=0xc0000000 (3072MB), size= 256MB: write-back, count=1
>> > reg03: base=0xcff00000 (3327MB), size= 1MB: uncachable, count=1
>> > reg04: base=0x100000000 (4096MB), size= 512MB: write-back, count=1
>> > reg05: base=0x120000000 (4608MB), size= 256MB: write-back, count=1
>> > reg06: base=0xd8000000 (3456MB), size= 128MB: write-combining, count=2
>> > Notice the first 3 entries are 3.25 GBytes (reg00, reg01 and reg02).
>> > The last 0.75GBytes are mapped above 4GByte (reg04 and reg05).
>> > -wolfgang
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