For CONFIG_PREEMPT_RT=y kernel, the "use_softirq=0" will be set, the RCU_SOFTIRQ processing is moved to per-CPU rcuc kthreads which created by smpboot_register_percpu_thread(). when CPU is going offline, the corresponding rcu_data.rcu_cpu_kthread_status is set RCU_KTHREAD_OFFCPU, and the rcuc kthreads enter TASK_PARKED state, kthreads in TASK_PARKED state only accept kthread_unpark() to wakeup. Therefore, This commit avoid invoke wake_up_process() to rcuc kthreads in TASK_PARKED state. Signed-off-by: Zqiang <qiang1.zhang@xxxxxxxxx> --- kernel/rcu/tree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 3ccad468887e..49dd87356851 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2375,7 +2375,8 @@ static void rcu_wake_cond(struct task_struct *t, int status) * If the thread is yielding, only wake it when this * is invoked from idle */ - if (t && (status != RCU_KTHREAD_YIELDING || is_idle_task(current))) + if (t && (status != RCU_KTHREAD_YIELDING || is_idle_task(current)) && + status != RCU_KTHREAD_OFFCPU) wake_up_process(t); } -- 2.25.1
