Re: [Patch] physnode_map definition should be signed

[Martin J. Bligh]

> In your modification of pfn_valid() for IA32 at 2.6.4 stock kernel,
> it doesn't return 0 even if the node is offline.
> 
> True problem is physnode_map's definition.
> Physnode_map[]'s default (offline) value is -1,
> but it is defined as UNSIGNED 8. 
> So, pfn_to_nid() return 255. 
> 
> I think this should be defined as signed like this patch.
> Maximum node number of IA32 is 16, so this is enough yet.
> 
> I found this problem on multi-node emulation for memory-hotplug test.
> When I started X on this emulation, system panicked at remap_pte_range()
> by this problem.
> I think that system will be down when a program will call mmap()
> for hardware area.

There are several breakages in this area, particularly on Summit with
4/4 split right now - in my tree I'm init'ing the array to 0 temporarily
to get around some problems, but we have better fixes lined up.

Anyway, your patch looks correct - 128 nodes should be plenty. I shall
apply it. Thanks,

M.

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