rt, nohz_full: fix nohz_full for PREEMPT_RT_FULL

[zynq/linux.git] / kernel / sched / core.c

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 43da2422df47b1ba8c82859cfa558e7511aa63a1..96f5efaeebeaea923d10e10ef972c81acd0e428a 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -742,14 +742,29 @@ static inline bool got_nohz_idle_kick(void)
 #endif /* CONFIG_NO_HZ_COMMON */
 
 #ifdef CONFIG_NO_HZ_FULL
+
+static int ksoftirqd_running(void)
+{
+       struct task_struct *softirqd;
+
+       if (!IS_ENABLED(CONFIG_PREEMPT_RT_FULL))
+               return 0;
+       softirqd = this_cpu_ksoftirqd();
+       if (softirqd && softirqd->on_rq)
+               return 1;
+       return 0;
+}
+
 bool sched_can_stop_tick(void)
 {
        /*
         * More than one running task need preemption.
         * nr_running update is assumed to be visible
         * after IPI is sent from wakers.
+        *
+        * NOTE, RT: if ksoftirqd is awake, subtract it.
         */
-       if (this_rq()->nr_running > 1)
+       if (this_rq()->nr_running - ksoftirqd_running() > 1)
                return false;
 
        return true;