Re: [PATCH 0/3] NUMA boot hash allocation interleaving

Martin J. Bligh
2004-12-15T15:09:11Z

--Andi Kleen <ak@suse.de> wrote (on Wednesday, December 15, 2004 08:17:34 +0100):

> On Tue, Dec 14, 2004 at 11:14:46PM -0800, Martin J. Bligh wrote:
>> Well hold on a sec. We don't need to use the hugepages pool for this,
>> do we? This is the same as using huge page mappings for the whole of
>> kernel space on ia32. As long as it's a kernel mapping, and 16MB aligned
>> and contig, we get it for free, surely?
>
> The whole point of the patch is to not use the direct mapping, but
> use a different interleaved mapping on NUMA machines to spread
> the memory out over multiple nodes.

Right, I know it's not there pre-existant - I was thinking of frigging it
by hand though, rather than using the hugepage pool infrastructure.

>> > Using other page sizes would be probably tricky because the
>> > linux VM can currently barely deal with two page sizes.
>> > I suspect handling more would need some VM infrastructure effort
>> > at least in the changed port.
>>
>> For the general case I'd agree. But this is a setup-time only tweak
>> of the static kernel mapping, isn't it?
>
> It's probably not impossible, just lots of ugly special cases.
> e.g. how about supporting it for /proc/kcore etc?

Hmmm. Yes, not considered those.

M.