Re: [PATCH] sched: Don't try allocating memory from offline nodes

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

On Tue, 2012-05-29 at 20:21 -0700, David Rientjes wrote:
> On Tue, 29 May 2012, Luck, Tony wrote:
> 
> > Index: linux-2.6/kernel/sched/core.c
> > ===================================================================
> > --- linux-2.6.orig/kernel/sched/core.c
> > +++ linux-2.6/kernel/sched/core.c
> > @@ -6449,7 +6449,7 @@ static void sched_init_numa(void)
> >  			return;
> >  
> >  		for (j = 0; j < nr_node_ids; j++) {
> > -			struct cpumask *mask = kzalloc_node(cpumask_size(), GFP_KERNEL, j);
> > +			struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL);
> >  			if (!mask)
> >  				return;
> >  
> 
> It's definitely better if we can allocate on the node, though, so perhaps 
> do the same thing that I did in 
> http://marc.info/?l=linux-kernel&m=133778739503111 by doing
> kzalloc_node(..., node_online(j) ? j : NUMA_NO_NODE)?

This data isn't used overly much, only when rebuilding the sched
domains, so its not performance critical. I only used per-node
allocations because it seemed the right thing to do. If it doesn't work,
I wouldn't bother with making it more complex.