It does, because it's a hack to extend 32-bit machines beyond their
architectural lifetime.
> - How much memory can Linux use without highmem enabled? (I've heard it's
> 1GB, but Linux found 1,2GB without ...)
On i386, it supports 896 MB without HIGHMEM.
> - How much is a system slowed down?
Depends completely on your application mix and amount of RAM -- and
whether or not you're using 4G or 64G HIGHMEM, the latter being more
severe across a whole bunch of axes.
> - How can this be fixed? I've heard it's a PCI issue (stuff being memory
> mapped above the 2GB limit?)
Go to a 64-bit CPU architecture.
-hpa
-- <hpa@transmeta.com> at work, <hpa@zytor.com> in private! "Unix gives you enough rope to shoot yourself in the foot." http://www.zytor.com/~hpa/puzzle.txt <amsp@zytor.com> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/