1 files changed, 56 insertions, 0 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 7d8b85fcdf06..9e3ede120e81 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -556,6 +556,10 @@ struct rq {
         unsigned int ttwu_count;
         unsigned int ttwu_local;
 #endif
+
+#ifdef CONFIG_SMP
+        struct task_struct *wake_list;
+#endif
 };
 
 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
@@ -2516,10 +2520,61 @@ static int ttwu_remote(struct task_struct *p, int wake_flags)
         return ret;
 }
 
+#ifdef CONFIG_SMP
+static void sched_ttwu_pending(void)
+{
+        struct rq *rq = this_rq();
+        struct task_struct *list = xchg(&rq->wake_list, NULL);
+
+        if (!list)
+                return;
+
+        raw_spin_lock(&rq->lock);
+
+        while (list) {
+                struct task_struct *p = list;
+                list = list->wake_entry;
+                ttwu_do_activate(rq, p, 0);
+        }
+
+        raw_spin_unlock(&rq->lock);
+}
+
+void scheduler_ipi(void)
+{
+        sched_ttwu_pending();
+}
+
+static void ttwu_queue_remote(struct task_struct *p, int cpu)
+{
+        struct rq *rq = cpu_rq(cpu);
+        struct task_struct *next = rq->wake_list;
+
+        for (;;) {
+                struct task_struct *old = next;
+
+                p->wake_entry = next;
+                next = cmpxchg(&rq->wake_list, old, p);
+                if (next == old)
+                        break;
+        }
+
+        if (!next)
+                smp_send_reschedule(cpu);
+}
+#endif
+
 static void ttwu_queue(struct task_struct *p, int cpu)
 {
         struct rq *rq = cpu_rq(cpu);
 
+#if defined(CONFIG_SMP) && defined(CONFIG_SCHED_TTWU_QUEUE)
+        if (sched_feat(TTWU_QUEUE) && cpu != smp_processor_id()) {
+                ttwu_queue_remote(p, cpu);
+                return;
+        }
+#endif
+
         raw_spin_lock(&rq->lock);
         ttwu_do_activate(rq, p, 0);
         raw_spin_unlock(&rq->lock);
@@ -6331,6 +6386,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
 
 #ifdef CONFIG_HOTPLUG_CPU
         case CPU_DYING:
+                sched_ttwu_pending();
                 /* Update our root-domain */
                 raw_spin_lock_irqsave(&rq->lock, flags);
                 if (rq->rd) {