Re: [PATCH 0/2] Relax restrictions on setting CONFIG_NUMA on x86

[Ingo Molnar]

* Mel Gorman <mel@xxxxxxxxx> wrote:

> [...] I tested this situation on a 4-node NUMA Opteron box. It didn't 
> work very well based on a few problems.
> 
> - alloc_remap() and SPARSEMEM on HIGHMEM4G explodes [1]
> - Without SRAT, there is a build failure 
> - Enabling SRAT requires BOOT_IOREMAP and it explodes early in boot
> 
> I have one fix for items 1 and 2 with the patch below. It probably 
> should be split in two but lets see if we want to pursue alternative 
> fixes to this problem first. In particular, this patch stops SPARSEMEM 
> using alloc_remap() because not enough memory is set aside. An 
> alternative solution may be to reserve more for alloc_remap() when 
> SPARSEMEM is in use.
> 
> With the patch applied, an x86-64 capable NUMA Opteron box will boot a 
> 32 bit NUMA enabled kernel with DISCONTIGMEM or SPARSEMEM. Due to the 
> lack of SRAT parsing, there is only node 0 of course.
> 
> Based on this, I have no doubt there is going to be a series of broken 
> boots while stuff like this gets rattled out. For the moment, NUMA on 
> x86 32-bit should remain CONFIG_EXPERIMENTAL.

thanks, applied.

	Ingo
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