[RFC PATCH v2 1/2] powerpc: numa: enable USE_PERCPU_NUMA_NODE_ID

[Nishanth Aravamudan]

On 19.05.2014 [11:14:23 -0700], Nishanth Aravamudan wrote:
> Hi Andrew,
> 
> I found one issue with my patch, fixed below...
> 
> On 16.05.2014 [16:39:45 -0700], Nishanth Aravamudan wrote:
> > Based off 3bccd996 for ia64, convert powerpc to use the generic per-CPU
> > topology tracking, specifically:
> >     
> > 	initialize per cpu numa_node entry in start_secondary
> >     	remove the powerpc cpu_to_node()
> >     	define CONFIG_USE_PERCPU_NUMA_NODE_ID if NUMA
> >     
> > Signed-off-by: Nishanth Aravamudan <nacc at linux.vnet.ibm.com>
> 
> <snip>
> 
> > diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> > index e2a4232..b95be24 100644
> > --- a/arch/powerpc/kernel/smp.c
> > +++ b/arch/powerpc/kernel/smp.c
> > @@ -750,6 +750,11 @@ void start_secondary(void *unused)
> >  	}
> >  	traverse_core_siblings(cpu, true);
> >  
> > +	/*
> > +	 * numa_node_id() works after this.
> > +	 */
> > +	set_numa_node(numa_cpu_lookup_table[cpu]);
> > +
> 
> Similar change is needed for the boot CPU. Update patch:
> 
> 
> powerpc: numa: enable USE_PERCPU_NUMA_NODE_ID
>     
> Based off 3bccd996 for ia64, convert powerpc to use the generic per-CPU
> topology tracking, specifically:
>     
>     initialize per cpu numa_node entry in start_secondary
>     remove the powerpc cpu_to_node()
>     define CONFIG_USE_PERCPU_NUMA_NODE_ID if NUMA
>     
> Signed-off-by: Nishanth Aravamudan <nacc at linux.vnet.ibm.com>

Ping on this and patch 2/2. Ben, would you be willing to pull these into
your -next branch so they'd get some testing?

http://patchwork.ozlabs.org/patch/350368/
http://patchwork.ozlabs.org/patch/349838/

Without any further changes, these two help quite a bit with the slab
consumption on CONFIG_SLUB kernels when memoryless nodes are present.

Thanks,
Nish