2 files changed, 28 insertions, 0 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 86ea9e34e326..6090d18b58a9 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1886,6 +1886,12 @@ static void common_cpu_mem_hotplug_unplug(void)
         top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
         scan_for_empty_cpusets(&top_cpuset);
 
+        /*
+         * Scheduler destroys domains on hotplug events.
+         * Rebuild them based on the current settings.
+         */
+        rebuild_sched_domains();
+
         cgroup_unlock();
 }
 
diff --git a/kernel/sched.c b/kernel/sched.c
index f0ed81b71282..1ddb0a8c7976 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7293,6 +7293,18 @@ void __attribute__((weak)) arch_update_cpu_topology(void)
 }
 
 /*
+ * Free current domain masks.
+ * Called after all cpus are attached to NULL domain.
+ */
+static void free_sched_domains(void)
+{
+        ndoms_cur = 0;
+        if (doms_cur != &fallback_doms)
+                kfree(doms_cur);
+        doms_cur = &fallback_doms;
+}
+
+/*
  * Set up scheduler domains and groups. Callers must hold the hotplug lock.
  * For now this just excludes isolated cpus, but could be used to
  * exclude other special cases in the future.
@@ -7439,6 +7451,7 @@ int arch_reinit_sched_domains(void)
         get_online_cpus();
         mutex_lock(&sched_domains_mutex);
         detach_destroy_domains(&cpu_online_map);
+        free_sched_domains();
         err = arch_init_sched_domains(&cpu_online_map);
         mutex_unlock(&sched_domains_mutex);
         put_online_cpus();
@@ -7524,6 +7537,7 @@ static int update_sched_domains(struct notifier_block *nfb,
         case CPU_DOWN_PREPARE:
         case CPU_DOWN_PREPARE_FROZEN:
                 detach_destroy_domains(&cpu_online_map);
+                free_sched_domains();
                 return NOTIFY_OK;
 
         case CPU_UP_CANCELED:
@@ -7542,8 +7556,16 @@ static int update_sched_domains(struct notifier_block *nfb,
                 return NOTIFY_DONE;
         }
 
+#ifndef CONFIG_CPUSETS
+        /*
+         * Create default domain partitioning if cpusets are disabled.
+         * Otherwise we let cpusets rebuild the domains based on the
+         * current setup.
+         */
+
         /* The hotplug lock is already held by cpu_up/cpu_down */
         arch_init_sched_domains(&cpu_online_map);
+#endif
 
         return NOTIFY_OK;
 }