Bug#295678: kernel-image packages with CONFIG_HIGHMEM64G=y enabled
> I can't say I'm a fan of adding another flavour. How many people are
> actually using >4GB of memory on x86? I suspect (or hope) that people
> who are going to be doing those sorts of things will be using x86_64
> and ia64 hardware. Christian's problem, aiui, is simply that the kernel
> sees 3.5GB instead of 4GB. I'm not sure whether this is by design, or is
> a bug, but I'd much rather see that fixed instead.
This is not really a bug, see:
http://lists.us.dell.com/fom-serve/cache/68.html
http://lists.us.dell.com/pipermail/linux-poweredge/2004-November/017335.html
http://lists.us.dell.com/pipermail/linux-poweredge/2004-November/017342.html
The 3.5GB-4GB address space is reserved for PCI devices, so, as only 4GB
can be adressed on 32bits proc, there is an address space shortage which
prevents using the 3.5GB-4GB RAM.
So the only solution is to enable CONFIG_HIGHMEM64G to increase the
address space so that the 3.5GB-4GB RAM become addresseable.
However I would be interested in some numbers/benchmarks on the
performance penalty of the PAE mode. Is this worth 512MB of additionnal
RAM ?
Yann
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