Re: [patch 2/2] enables booting a NUMA system where some nodes haveno memory

[Martin J. Bligh]

Christian Krafft wrote:
> On Wed, 15 Nov 2006 16:57:56 -0800 (PST)
> Christoph Lameter <clameter@xxxxxxx> wrote:
>
> > On Thu, 16 Nov 2006, KAMEZAWA Hiroyuki wrote:
> >
> > > > But there is no memory on the node. Does the zonelist contain the zones of 
> > > > the node without memory or not? We simply fall back each allocation to the 
> > > > next node as if the node was overflowing?
> > > yes. just fallback.
> > Ok, so we got a useless pglist_data struct and the struct zone contains a 
> > zonelist that does not include the zone.
>
> Okay, I slowly understand what you are talking about.
> I just tried a "numactl --cpunodebind 1 --membind 1 true" which hit an uninitialized zone in slab_node:
>
> return zone_to_nid(policy->v.zonelist->zones[0]);
>
> I also still don't know if it makes sense to have memoryless nodes, but supporting it does.
> So wath would be reasonable, to have empty zonelists for those node, or to check if zonelists are uninitialized ?

You don't want empty zonelists on a node containing CPUs, else it won't
know where to allocate from. You just want to make sure that the zones
in that node (if existant) are not contained in *anyone's* zonelist.

M.

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