On 17.02.2014 [15:14:06 -0800], David Rientjes wrote:
> On Mon, 17 Feb 2014, Nishanth Aravamudan wrote:
>
> > Here is what I'm running into now:
> >
> > setup_arch ->
> > do_init_bootmem ->
> > cpu_numa_callback ->
> > numa_setup_cpu ->
> > map_cpu_to_node ->
> > update_numa_cpu_lookup_table
> >
> > Which current updates the powerpc specific numa_cpu_lookup_table. I
> > would like to update that function to use set_cpu_numa_node() and
> > set_cpu_numa_mem(), but local_memory_node() is not yet functional
> > because build_all_zonelists is called later in start_kernel. Would it
> > make sense for first_zones_zonelist() to return NUMA_NO_NODE if we
> > don't have a zone?
> >
>
> Hmm, I don't think we'll want to modify the generic first_zones_zonelist()
> for a special case that is only true during boot. Instead, would it make
> sense to modify numa_setup_cpu() to use the generic cpu_to_node() instead
> of using a powerpc mapping and then do the set_cpu_numa_mem() after
> paging_init() when the zonelists will have been built and zones without
> present pages are properly excluded?
Sorry, I was unclear in my e-mail. I meant to modify
local_memory_node(), not first_zones_zonelist(). Well, it only needs the
following, I think?
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e3758a0..5de4337 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3650,6 +3650,8 @@ int local_memory_node(int node)
gfp_zone(GFP_KERNEL),
NULL,
&zone);
+ if (!zone)
+ return NUMA_NO_NODE;
return zone->node;
}
#endif
I think that condition should only happen during boot -- maybe even
deserving of an unlikely, but I don't think the above is considered a
hot-path. If the above isn't palatable, I can look into your suggestion
instead.
Thanks,
Nish
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