Re: [2/8,v3] NUMA Hotplug Emulator: infrastructure of NUMA hotplug emulation

[Shaohui Zheng <shaohui.zheng@intel.com>]

On Thu, Nov 18, 2010 at 03:27:15PM +0900, Paul Mundt wrote:
> On Thu, Nov 18, 2010 at 12:14:07PM +0800, Shaohui Zheng wrote:
> > On Wed, Nov 17, 2010 at 01:10:50PM -0800, David Rientjes wrote:
> > > The idea that I've proposed (and you've apparently thought about and even 
> > > implemented at one point) is much more powerful than that.  We need not 
> > > query the state of hidden nodes that we've setup at boot but can rather 
> > > use the amount of hidden memory to setup the nodes in any way that we want 
> > > at runtime (various sizes, interleaved node ids, etc).
> > 
> > yes, if we select your proposal. we just mark all the nodes as POSSIBLE node.
> > there is no hidden nodes any more. the node will be created after add memory
> > to the node first time. 
> > 
> This is roughly what I had in mind in my N_HIDDEN review, so I quite
> favour this approach.

Our testing shows that it is a feasible approach, and it works well.
however, there is still a problem which we should worry about.

in our draft patch, we re-setup nr_node_ids when CONFIG_ARCH_MEMORY_PROBE enabled 
and mem=XXX was specified in grub. we set nr_node_ids as MAX_NUMNODES + 1, because
 we do not know how many nodes will be hot-added through memory/probe interface. 
 it might be a little wasting of memory.

-- 
Thanks & Regards,
Shaohui