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Date: Sun, 21 Nov 2010 13:46:07 -0800 (PST)
From: David Rientjes <rientjes@google.com>
To: =?UTF-8?Q?Am=C3=A9rico_Wang?= <xiyou.wangcong@gmail.com>
cc: Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Greg Kroah-Hartman <gregkh@suse.de>,
        Shaohui Zheng <shaohui.zheng@intel.com>,
        Paul Mundt <lethal@linux-sh.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andi Kleen <ak@linux.intel.com>, Yinghai Lu <yinghai@kernel.org>,
        Haicheng Li <haicheng.li@intel.com>,
        Randy Dunlap <randy.dunlap@oracle.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, x86@kernel.org
Subject: Re: [patch 1/2] x86: add numa=possible command line option
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On Sun, 21 Nov 2010, Américo Wang wrote:

> I am not sure how much value of making this dynamic,
> for CPU, we do this at compile time, i.e. NR_CPUS,
> so how about NR_NODES?
> 

This is outside the scope of node hotplug emulation, it needs to be built 
on top of whatever the kernel implements.

> Also, numa=possible= is not as clear as numa=max=, for me at least.
> 

I like name, but it requires that you know how many nodes that system 
already has.  In other words, numa=possible=4 allows you to specify that 4 
additional nodes will be possible, but initially offline, for this or 
other purposes.  numa=max=4 would be no-op if the system actually had 4 
nodes.

I chose numa=possible over numa=additional because it is more clearly tied 
to node_possible_map, which is the only thing it modifies.
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