[PATCH] powerpc/numa: Invalidate numa_cpu_lookup_table on cpu remove

[Nathan Fontenot]

When DLPAR removing a CPU, the unmapping of the cpu from a node in
unmap_cpu_from_node() should also invalidate the CPUs entry in the
numa_cpu_lookup_table. There is not a guarantee that on a subsequent
DLPAR add of the CPU the associativity will be the same and thus
could be in a different node. Invalidating the entry in the
numa_cpu_lookup_table causes the associativity to be read from the
device tree at the time of the add.

The current behavior of not invalidating the CPUs entry in the
numa_cpu_lookup_table can result in scenarios where the the topology
layout of CPUs in the partition does not match the device tree
or the topology reported by the HMC.

Signed-off-by: Nathan Fontenot <nfont at linux.vnet.ibm.com>
---
 arch/powerpc/mm/numa.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index adb6364f4091..415b1a76b429 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -164,6 +164,8 @@ static void unmap_cpu_from_node(unsigned long cpu)
 
 	dbg("removing cpu %lu from node %d\n", cpu, node);
 
+	update_numa_cpu_lookup_table(cpu, -1);
+
 	if (cpumask_test_cpu(cpu, node_to_cpumask_map[node])) {
 		cpumask_clear_cpu(cpu, node_to_cpumask_map[node]);
 	} else {