Re: [RFC] hotplug memory remove - walk_memory_resource for ppc64

[Badari Pulavarty <pbadari@us.ibm.com>]

On Wed, 2007-10-31 at 14:34 +0900, KAMEZAWA Hiroyuki wrote:
> On Wed, 31 Oct 2007 14:28:46 +0900
> KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> 
> > ioresource was good structure for remembering "which memory is conventional
> > memory" and i386/x86_64/ia64 registered conventional memory as "System RAM",
> > when I posted patch. (just say "System Ram" is not for memory hotplug.)
> > 
> If I remember correctly, System RAM is for kdump (to know which memory should
> be dumped.) Then, memory-hotadd/remove has to modify it anyway.

Yes. kdump uses it for finding memory holes on x86/x86-64 (not sure
about ia64). On PPC64, since its not represented in /proc/iomem, we
end up reading /proc/device-tree/memory* nodes to construct the 
memory map.

Paul's concern is, since we didn't need it so far - why we need this
for hotplug memory remove to work ? It might break API for *unknown*
applications. Its unfortunate that, hotplug memory add updates 
/proc/iomem. We can deal with it later, as a separate patch.

Thanks,
Badari

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