On Wed, May 02, 2007 at 09:22:58AM -0700, Luck, Tony wrote: > > This seems line an issue best solved by prohibiting such settings through > > Kconfig. But if it is desirable for sparse and discontig memory to work > > without CONFIG_NUMA let me know and I'll have a stab at it. It does seem > > possible code-wise. I'm just not sure if its useful. > > I pretty sure that we used to be able to build for a DISCONTIG but > non-NUMA system ... this is a quite common case, systems with >4G > of memory put the first 2G at 0-2G, reserve the 2G-4G area for > PCI memory mapped devices (and other platform specific stuff) then > the rest of RAM is at some >4G address. With just a 2G hole it > is possible to paper over it, but some systems put the extra > memory at much higher addresses. I did take a look at what it would take to allow Sparse to compile in non-NUMA. It seemed that Sparse was very much centered around NUMA so I wondered how useful the result might be. I will take a look into Discontig and see what is required there. > But it would be nice to reduce the CONFIG maze ... so perhaps we > should ponder what overhead such a system would suffer by having > to be built as CONFIG_NUMA=y. If this is small, then perhaps we > can simplify things. I guess it might be a bit tricky to measure that comprehensively. But it would certainly make things easier. I think that the patch I sent implements what you are suggesting, though perhaps it isn't exactly what you had in mind. -- Horms H: http://www.vergenet.net/~horms/ W: http://www.valinux.co.jp/en/ - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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