1 files changed, 45 insertions, 63 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 1ee18dbb4516..c237624a8a04 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2881,7 +2881,7 @@ static void sched_migrate_task(struct task_struct *p, int dest_cpu)
 
         rq = task_rq_lock(p, &flags);
         if (!cpu_isset(dest_cpu, p->cpus_allowed)
-            || unlikely(cpu_is_offline(dest_cpu)))
+            || unlikely(!cpu_active(dest_cpu)))
                 goto out;
 
         /* force the process onto the specified CPU */
@@ -3849,7 +3849,7 @@ int select_nohz_load_balancer(int stop_tick)
                 /*
                  * If we are going offline and still the leader, give up!
                  */
-                if (cpu_is_offline(cpu) &&
+                if (!cpu_active(cpu) &&
                     atomic_read(&nohz.load_balancer) == cpu) {
                         if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
                                 BUG();
@@ -5876,7 +5876,7 @@ static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
         struct rq *rq_dest, *rq_src;
         int ret = 0, on_rq;
 
-        if (unlikely(cpu_is_offline(dest_cpu)))
+        if (unlikely(!cpu_active(dest_cpu)))
                 return ret;
 
         rq_src = cpu_rq(src_cpu);
@@ -7554,18 +7554,6 @@ 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.
@@ -7643,7 +7631,7 @@ static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
  * ownership of it and will kfree it when done with it. If the caller
  * failed the kmalloc call, then it can pass in doms_new == NULL,
  * and partition_sched_domains() will fallback to the single partition
- * 'fallback_doms'.
+ * 'fallback_doms', it also forces the domains to be rebuilt.
  *
  * Call with hotplug lock held
  */
@@ -7657,12 +7645,8 @@ void partition_sched_domains(int ndoms_new, cpumask_t *doms_new,
         /* always unregister in case we don't destroy any domains */
         unregister_sched_domain_sysctl();
 
-        if (doms_new == NULL) {
-                ndoms_new = 1;
-                doms_new = &fallback_doms;
-                cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map);
-                dattr_new = NULL;
-        }
+        if (doms_new == NULL)
+                ndoms_new = 0;
 
         /* Destroy deleted domains */
         for (i = 0; i < ndoms_cur; i++) {
@@ -7677,6 +7661,14 @@ match1:
                 ;
         }
 
+        if (doms_new == NULL) {
+                ndoms_cur = 0;
+                ndoms_new = 1;
+                doms_new = &fallback_doms;
+                cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map);
+                dattr_new = NULL;
+        }
+
         /* Build new domains */
         for (i = 0; i < ndoms_new; i++) {
                 for (j = 0; j < ndoms_cur; j++) {
@@ -7707,17 +7699,10 @@ match2:
 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
 int arch_reinit_sched_domains(void)
 {
-        int err;
-
         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);
+        rebuild_sched_domains();
         put_online_cpus();
-
-        return err;
+        return 0;
 }
 
 static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
@@ -7783,59 +7768,49 @@ int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
 }
 #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
 
+#ifndef CONFIG_CPUSETS
 /*
- * Force a reinitialization of the sched domains hierarchy. The domains
- * and groups cannot be updated in place without racing with the balancing
- * code, so we temporarily attach all running cpus to the NULL domain
- * which will prevent rebalancing while the sched domains are recalculated.
+ * Add online and remove offline CPUs from the scheduler domains.
+ * When cpusets are enabled they take over this function.
  */
 static int update_sched_domains(struct notifier_block *nfb,
                                 unsigned long action, void *hcpu)
 {
+        switch (action) {
+        case CPU_ONLINE:
+        case CPU_ONLINE_FROZEN:
+        case CPU_DEAD:
+        case CPU_DEAD_FROZEN:
+                partition_sched_domains(0, NULL, NULL);
+                return NOTIFY_OK;
+
+        default:
+                return NOTIFY_DONE;
+        }
+}
+#endif
+
+static int update_runtime(struct notifier_block *nfb,
+                                unsigned long action, void *hcpu)
+{
         int cpu = (int)(long)hcpu;
 
         switch (action) {
         case CPU_DOWN_PREPARE:
         case CPU_DOWN_PREPARE_FROZEN:
                 disable_runtime(cpu_rq(cpu));
-                /* fall-through */
-        case CPU_UP_PREPARE:
-        case CPU_UP_PREPARE_FROZEN:
-                detach_destroy_domains(&cpu_online_map);
-                free_sched_domains();
                 return NOTIFY_OK;
 
-
         case CPU_DOWN_FAILED:
         case CPU_DOWN_FAILED_FROZEN:
         case CPU_ONLINE:
         case CPU_ONLINE_FROZEN:
                 enable_runtime(cpu_rq(cpu));
-                /* fall-through */
-        case CPU_UP_CANCELED:
-        case CPU_UP_CANCELED_FROZEN:
-        case CPU_DEAD:
-        case CPU_DEAD_FROZEN:
-                /*
-                 * Fall through and re-initialise the domains.
-                 */
-                break;
+                return NOTIFY_OK;
+
         default:
                 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;
 }
 
 void __init sched_init_smp(void)
@@ -7855,8 +7830,15 @@ void __init sched_init_smp(void)
                 cpu_set(smp_processor_id(), non_isolated_cpus);
         mutex_unlock(&sched_domains_mutex);
         put_online_cpus();
+
+#ifndef CONFIG_CPUSETS
         /* XXX: Theoretical race here - CPU may be hotplugged now */
         hotcpu_notifier(update_sched_domains, 0);
+#endif
+
+        /* RT runtime code needs to handle some hotplug events */
+        hotcpu_notifier(update_runtime, 0);
+
         init_hrtick();
 
         /* Move init over to a non-isolated CPU */