FC6 kernels & 4GB of memory

[Darryl]

Darryl wrote:
> Quoting "Wolfgang S. Rupprecht"
>  >To see your memory layout check /proc/mtrr.
> 
> Ok, this is from 32bit PAE kernel:
> $ 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=0xd0000000 (3328MB), size= 128MB: write-combining, count=1
> 
>  >  reset to factory "optimized" settings.
> Did that after the last BIOS update.
> 
>  >  select mtrr discontinuous          (was contigious)
> That option disappeared with a BIOS update actually. a new one popped up 
> regarding Virtual stuff though.
> 
>  >  select mtrr hardware mapping          (was disabled)
>  >  select iommu 128k                  (was disabled)
> BIOS doesn't have those options.
> 
> I tried downloading the latest/greatest 2.6.21 kernel and compiling my 
> own 32bit "PAE" & "regular" kernels but they did the same thing. 
> "regular" sees all the memory but tells me to use a PAE kernel and "PAE" 
>  won't use all the memory and crashes on boot without mem=4095m. A 
> little frustrating since the "regular" kernel and memtest86 see all the 
> memory. The good news is that the on-board NIC is natively supported in 
> .21 though :-/
> 

The M2V BIOS was just updated to 1802 but it didn't make a difference 
for kernel 2.6.21-3228.fc7PAE which would panic on boot with a

mount: could not find filesystem '/dev/root'

message. Adding 'mem=4096m' to the command line would allow the system 
to boot but free would show '3375576 total' which is some 700MB shy.


New kernel 2.6.22.1-27.fc7PAE now boots without command line options and:
free
            total       used       free     shared    buffers     cached
Mem:     4149648    3964376     185272          0     174440    3586788
-/+ buffers/cache:   203148    3946500
Swap:            0          0          0

is showing what I had hoped for originally :-) /proc/mtrr shows the same 
as it did before:

# 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=0xd0000000 (3328MB), size= 128MB: write-combining, count=1

is that correct?