Messages in this thread | | | From | Andi Kleen <> | Subject | Re: [PATCH 1/1] mm: Inconsistent use of node IDs | Date | Tue, 13 Mar 2007 00:19:30 +0100 |
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On Monday 12 March 2007 23:51, Ethan Solomita wrote: > This patch corrects inconsistent use of node numbers (variously "nid" or > "node") in the presence of fake NUMA.
I think it's very consistent -- your patch would make it inconsistent though.
> Both AMD and Intel x86_64 discovery code will determine a CPU's physical > node and use that node when calling numa_add_cpu() to associate that CPU > with the node, but numa_add_cpu() treats the node argument as a fake > node. This physical node may not exist within the fake nodespace, and > even if it does, it will likely incorrectly associate a CPU with a fake > memory node that may not share the same underlying physical NUMA node. > > Similarly, the PCI code which determines the node of the PCI bus saves > it in the pci_sysdata structure. This node then propagates down to other > buses and devices which hang off the PCI bus, and is used to specify a > node when allocating memory. The purpose is to provide NUMA locality, > but the node is a physical node, and the memory allocation code expects > a fake node argument.
Sorry, but when you ask for NUMA emulation you will get it. I don't see any point in a "half way only for some subsystems I like" NUMA emulation. It's unlikely that your ideas of where it is useful and where is not matches other NUMA emulation user's ideas too.
Besides adding such a secondary node space would be likely a huge long term mainteance issue. I just can it see breaking with every non trivial change.
NACK.
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