Pre-loaded mfsroot size and FreeBSD 4.9 with 4G RAM

[John Baldwin]

On Sunday 12 February 2006 00:37, Sergey Babkin wrote:
> Jacques Fourie wrote:
> > I have installed 6.0-RELEASE and the behaviour is still the same. If I
> > try to pre-load an md_image of 64M with 4G of RAM installed, the kernel
> > panics early in the boot cycle. Here is the panic on 6.0-RELEASE:
> >
> > 131072K of memory above 4GB ignored
>
> This is a kind of stupid question but is there any chance that the 64MB
> image overlaps with the PCI address hole? To elaborate: with
> 4GB memory installed there would be no address range to access the
> memory-mapped 32-bit PCI cards. So the motherboard circuitry
> relocates some amount of memory (the 128MB shown above) from
> some lower address to above 4GB and frees this address space below
> 4GB for mapping of the PCI cards. So the interesting question
> is: what is the address of this PCI hole and what is the loading
> address of the FreeBSD md_image? If they overlap then naturally
> a part of the image would go into nowhere and cause a panic.
>
> On my machine this PCI hole can be disabled in BIOS (I think so,
> there is also some kind of configuration in BIOS but I did
> not pay much attention to it as I don't have 4GB).

No, that won't happen as the mfsroot is loaded into RAM, and RAM doesn't 
conflict with the PCI addreses.

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org