Date: Fri, 09 Apr 2004 11:37:45 +0900
From: IWAMOTO Toshihiro <iwamoto@valinux.co.jp>
To: "Martin J. Bligh" <mbligh@aracnet.com>
Cc: IWAMOTO Toshihiro <iwamoto@valinux.co.jp>, linux-kernel@vger.kernel.org,
       lhms-devel@lists.sourceforge.net
Subject: Re: [patch 0/3] memory hotplug prototype
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At Thu, 08 Apr 2004 09:56:35 -0700,
Martin J. Bligh <mbligh@aracnet.com> wrote:
> 
> > At Wed, 07 Apr 2004 11:12:55 -0700,
> > Martin J. Bligh <mbligh@aracnet.com> wrote:
> >> 
> >> > This is an updated version of memory hotplug prototype patch, which I
> >> > have posted here several times.
> >> 
> >> I really, really suggest you take a look at Dave McCracken's work, which
> >> he posted as "Basic nonlinear for x86" recently. It's going to be much
> >> much easier to use this abstraction than creating 1000s of zones ...
> > 
> > Well, I think his patch is orthogonal to mine.  My ultimate target
> > is IA64 and it will only support node-sized memory hotplugging.
> 
> Are you saying you're only creating a patch for ia64 only, rather than
> an arch-independant one?

I'm not trying to make my patches IA64 specific, and my patch is quite
machine independent.  However, some of them, such as placing mem_map at
boot time or hotplug events, are machine dependent by nature.

I'm afraid that the memsection thing is overkill for systems whose
hotpluggable memory unit is large.  I understand there's need for
memsection, but I think that should be optional.

BTW, I think memory hotplugging on 32 bit archs are difficult because
of their narrow address space.  For example:
	1. A system boots with 1GB * 4 blocks of RAM.
	2. The second RAM block is removed.
	3. A 2GB block is inserted in the second slot.
Where does these RAM block appear in physical space, and where should
their mem_map be placed?

--
IWAMOTO Toshihiro


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