Re: [discuss] Re: [RFC:PATCH(003/003)] Memory add to onlined node. (ver. 2) (For x86_64)

From: Andi Kleen
Date: Thu Feb 09 2006 - 05:40:16 EST


On Thursday 09 February 2006 10:50, Yasunori Goto wrote:

> Current code adds memory to ZONE_NORMAL like this.
> But, ZONE_DMA32 is available on 2.6.15. So, I'm afraid there are
> 2 types trouble.
>
> a) When new memory is added to < 4GB, this should be added to
> Zone_DMA32.
> Are there any real machine which allow to add memory under
> 4GB?

x86-64 machines usually use a continuous memory map
because Windows gets unhappy with too big memory holes (and even
Linux is not completely troublefree for UP install kernels) And for a small
system this implies memory < 4GB.

> b) If machine boots up with under 4GB memory, and new memory
> is added to over 4GB, then kernel might panic due to Zone Normal's
> initialization is imcomplete.
>
> Q2)
> Are there any real machine which can add memory with NUMA feature?

There are and will be.

-Andi
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