Re: [Lse-tech] [RFC][PATCH] Change pcibus_to_cpumask() to pcibus_to_node()

[Jesse Barnes]

On Tuesday, July 27, 2004 2:51 am, Christoph Hellwig wrote:
> On Mon, Jul 26, 2004 at 05:10:08PM -0700, Matthew Dobson wrote:
> > So in discussions with Jesse at OLS, we decided that pcibus_to_node() is
>
> Please do pcibus_to_nodemask() instead - there could be dual-ported pci
> bridges.

Do you know of any?  On sn2 there are dual ported xio->pci bridges, but in 
that case, half the busses are associated with one node and the other half 
with another node, so pcibus_to_node would work in that case.  And for 
numalink->pci bridges, we'll return the node id of the bridge in that case 
(which may not have any memory, but in that case alloc_pages_node will fall 
back to the next node).

I wonder though if we shouldn't add

  ...
#ifdef CONFIG_NUMA
  int node; /* or nodemask_t if necessary */
#endif
  ...

to struct pci_bus instead?  That would make the existing code paths a little 
faster and avoid the need for a global array, which tends to lead to TLB 
misses.

Anyway, my needs are very simple.  I'd like to do 
alloc_pages_node(pci_to_node(pci_dev)); in the sn2 version of 
pci_alloc_consistent and use the new routine to simplify the initial irq 
setup code, making it look more like build_zonelists and the sched domains 
patch I posted yesterday.  So as long as those needs are provided for, I'm ok 
with the interface.

Thanks,
Jesse
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