Date: Mon, 13 Feb 2006 12:07:05 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-hackers@freebsd.org, babkin@users.sourceforge.net Subject: Re: Pre-loaded mfsroot size and FreeBSD 4.9 with 4G RAM Message-ID: <200602131207.07212.jhb@freebsd.org> In-Reply-To: <43EEC980.32C2FA40@verizon.net> References: <20060208164141.GA21718@trispen.com> <op.s4rjho0bwikogb@jf64x2.trispen.com> <43EEC980.32C2FA40@verizon.net>
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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@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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