From: Andi Kleen <ak@suse.de>
To: discuss@x86-64.org
Subject: Re: [discuss] Re: [RFC:PATCH(003/003)] Memory add to onlined node. (ver. 2) (For x86_64)
Date: Thu, 9 Feb 2006 11:41:43 +0100
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Cc: Yasunori Goto <y-goto@jp.fujitsu.com>,
       "Tolentino, Matthew E" <matthew.e.tolentino@intel.com>,
       "Brown, Len" <len.brown@intel.com>, naveen.b.s@intel.com,
       Bjorn Helgaas <bjorn.helgaas@hp.com>,
       Linux Kernel ML <linux-kernel@vger.kernel.org>,
       ACPI-ML <linux-acpi@vger.kernel.org>,
       Linux Hotplug Memory Support 
	<lhms-devel@lists.sourceforge.net>
References: <20060209153803.6CF4.Y-GOTO@jp.fujitsu.com> <20060209164036.6CFC.Y-GOTO@jp.fujitsu.com>
In-Reply-To: <20060209164036.6CFC.Y-GOTO@jp.fujitsu.com>
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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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