Commit 2c0a33f9 authored Oct 17, 2014 by Nishanth Aravamudan Committed by Michael Ellerman Oct 29, 2014

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>

parent 49f8d8c0

arch/powerpc/mm/numa.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -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();
		}

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