Re: [RFC Patch V1 00/30] Enable memoryless node on x86 platforms

From: H. Peter Anvin
Date: Fri Jul 11 2014 - 19:52:17 EST


On 07/11/2014 01:20 PM, Andi Kleen wrote:
> Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> writes:
>
>> On Fri, Jul 11, 2014 at 10:29:56AM +0200, Peter Zijlstra wrote:
>>> On Fri, Jul 11, 2014 at 03:37:17PM +0800, Jiang Liu wrote:
>>>> Any comments are welcomed!
>>>
>>> Why would anybody _ever_ have a memoryless node? That's ridiculous.
>>
>> I'm with Peter here, why would this be a situation that we should even
>> support? Are there machines out there shipping like this?
>
> We've always had memory nodes.
>
> A classic case in the old days was a two socket system where someone
> didn't populate any DIMMs on the second socket.
>
> There are other cases too.
>

Yes, like a node controller-based system where the system can be
populated with either memory cards or CPU cards, for example. Now you
can have both memoryless nodes and memory-only nodes...

Memory-only nodes also happen in real life. In some cases they are done
by permanently putting low-frequency CPUs to sleep for their memory
controllers.

-hpa


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/