1 files changed, 40 insertions, 14 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index dc0be113f41d..f0ed81b71282 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -529,6 +529,7 @@ struct rq {
         int push_cpu;
         /* cpu of this runqueue: */
         int cpu;
+        int online;
 
         struct task_struct *migration_thread;
         struct list_head migration_queue;
@@ -1498,6 +1499,8 @@ static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
 #endif
 
 #define sched_class_highest (&rt_sched_class)
+#define for_each_class(class) \
+   for (class = sched_class_highest; class; class = class->next)
 
 static inline void inc_load(struct rq *rq, const struct task_struct *p)
 {
@@ -6065,6 +6068,36 @@ static void unregister_sched_domain_sysctl(void)
 }
 #endif
 
+static void set_rq_online(struct rq *rq)
+{
+        if (!rq->online) {
+                const struct sched_class *class;
+
+                cpu_set(rq->cpu, rq->rd->online);
+                rq->online = 1;
+
+                for_each_class(class) {
+                        if (class->rq_online)
+                                class->rq_online(rq);
+                }
+        }
+}
+
+static void set_rq_offline(struct rq *rq)
+{
+        if (rq->online) {
+                const struct sched_class *class;
+
+                for_each_class(class) {
+                        if (class->rq_offline)
+                                class->rq_offline(rq);
+                }
+
+                cpu_clear(rq->cpu, rq->rd->online);
+                rq->online = 0;
+        }
+}
+
 /*
  * migration_call - callback that gets triggered when a CPU is added.
  * Here we can start up the necessary migration thread for the new CPU.
@@ -6102,7 +6135,8 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
                 spin_lock_irqsave(&rq->lock, flags);
                 if (rq->rd) {
                         BUG_ON(!cpu_isset(cpu, rq->rd->span));
-                        cpu_set(cpu, rq->rd->online);
+
+                        set_rq_online(rq);
                 }
                 spin_unlock_irqrestore(&rq->lock, flags);
                 break;
@@ -6163,7 +6197,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
                 spin_lock_irqsave(&rq->lock, flags);
                 if (rq->rd) {
                         BUG_ON(!cpu_isset(cpu, rq->rd->span));
-                        cpu_clear(cpu, rq->rd->online);
+                        set_rq_offline(rq);
                 }
                 spin_unlock_irqrestore(&rq->lock, flags);
                 break;
@@ -6385,20 +6419,16 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
 {
         unsigned long flags;
-        const struct sched_class *class;
 
         spin_lock_irqsave(&rq->lock, flags);
 
         if (rq->rd) {
                 struct root_domain *old_rd = rq->rd;
 
-                for (class = sched_class_highest; class; class = class->next) {
-                        if (class->leave_domain)
-                                class->leave_domain(rq);
-                }
+                if (cpu_isset(rq->cpu, old_rd->online))
+                        set_rq_offline(rq);
 
                 cpu_clear(rq->cpu, old_rd->span);
-                cpu_clear(rq->cpu, old_rd->online);
 
                 if (atomic_dec_and_test(&old_rd->refcount))
                         kfree(old_rd);
@@ -6409,12 +6439,7 @@ static void rq_attach_root(struct rq *rq, struct root_domain *rd)
 
         cpu_set(rq->cpu, rd->span);
         if (cpu_isset(rq->cpu, cpu_online_map))
-                cpu_set(rq->cpu, rd->online);
-
-        for (class = sched_class_highest; class; class = class->next) {
-                if (class->join_domain)
-                        class->join_domain(rq);
-        }
+                set_rq_online(rq);
 
         spin_unlock_irqrestore(&rq->lock, flags);
 }
@@ -7824,6 +7849,7 @@ void __init sched_init(void)
                 rq->next_balance = jiffies;
                 rq->push_cpu = 0;
                 rq->cpu = i;
+                rq->online = 0;
                 rq->migration_thread = NULL;
                 INIT_LIST_HEAD(&rq->migration_queue);
                 rq_attach_root(rq, &def_root_domain);