powerpc/numa: ensure per-cpu NUMA mappings are correct on topology update

We received a report of warning in kernel/sched/core.c where the sched
group was NULL on an LPAR after a topology update. This seems to occur
because after the topology update has moved the CPUs, cpu_to_node is
returning the old value still, which ends up breaking the consistency of
the NUMA topology in the per-cpu maps. Ensure that we update the per-cpu
fields when we re-map CPUs.

Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index ef45abf7319e..b9d1dfdbe5bb 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -1509,11 +1509,14 @@ static int update_cpu_topology(void *data)
         cpu = smp_processor_id();
 
         for (update = data; update; update = update->next) {
+                int new_nid = update->new_nid;
                 if (cpu != update->cpu)
                         continue;
 
                 unmap_cpu_from_node(cpu);
-                map_cpu_to_node(cpu, update->new_nid);
+                map_cpu_to_node(cpu, new_nid);
+                set_cpu_numa_node(cpu, new_nid);
+                set_cpu_numa_mem(cpu, local_memory_node(new_nid));
                 vdso_getcpu_init();
         }