2 files changed, 40 insertions, 1 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 10d51c2f10d7..c536e1c74320 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3370,6 +3370,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         e.g. base its process migration decisions on it.
                         Default is on.
 
+        topology_updates= [KNL, PPC, NUMA]
+                        Format: {off}
+                        Specify if the kernel should ignore (off)
+                        topology updates sent by the hypervisor to this
+                        LPAR.
+
         tp720=          [HW,PS2]
 
         tpm_suspend_pcr=[HW,TPM]
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 51d707d85b2d..177659050fa0 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -8,6 +8,8 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */
+#define pr_fmt(fmt) "numa: " fmt
+
 #include <linux/threads.h>
 #include <linux/bootmem.h>
 #include <linux/init.h>
@@ -1153,6 +1155,22 @@ static int __init early_numa(char *p)
 }
 early_param("numa", early_numa);
 
+static bool topology_updates_enabled = true;
+
+static int __init early_topology_updates(char *p)
+{
+        if (!p)
+                return 0;
+
+        if (!strcmp(p, "off")) {
+                pr_info("Disabling topology updates\n");
+                topology_updates_enabled = false;
+        }
+
+        return 0;
+}
+early_param("topology_updates", early_topology_updates);
+
 #ifdef CONFIG_MEMORY_HOTPLUG
 /*
  * Find the node associated with a hot added memory section for
@@ -1539,6 +1557,9 @@ int arch_update_cpu_topology(void)
         struct device *dev;
         int weight, new_nid, i = 0;
 
+        if (!prrn_enabled && !vphn_enabled)
+                return 0;
+
         weight = cpumask_weight(&cpu_associativity_changes_mask);
         if (!weight)
                 return 0;
@@ -1592,6 +1613,15 @@ int arch_update_cpu_topology(void)
                 cpu = cpu_last_thread_sibling(cpu);
         }
 
+        pr_debug("Topology update for the following CPUs:\n");
+        if (cpumask_weight(&updated_cpus)) {
+                for (ud = &updates[0]; ud; ud = ud->next) {
+                        pr_debug("cpu %d moving from node %d "
+                                          "to %d\n", ud->cpu,
+                                          ud->old_nid, ud->new_nid);
+                }
+        }
+
         /*
          * In cases where we have nothing to update (because the updates list
          * is too short or because the new topology is same as the old one),
@@ -1800,7 +1830,10 @@ static const struct file_operations topology_ops = {
 
 static int topology_update_init(void)
 {
-        start_topology_update();
+        /* Do not poll for changes if disabled at boot */
+        if (topology_updates_enabled)
+                start_topology_update();
+
         if (!proc_create("powerpc/topology_updates", 0644, NULL, &topology_ops))
                 return -ENOMEM;