From bfa45fec12076a38b29f2e3ab80410a1ae8ba10b Mon Sep 17 00:00:00 2001 From: Mike Galbraith Date: Fri, 20 Jan 2017 18:10:20 +0100 Subject: [PATCH 159/365] softirq: wake the timer softirq if needed The irq-exit path only checks the "normal"-softirq thread if it is running and ignores the state of the "timer"-softirq thread. It is possible that the timer-softirq thread is and has work pending which leads to the following warning: [ 84.087571] NOHZ: local_softirq_pending 02 [ 84.087593] NOHZ: local_softirq_pending 02 [ 84.087598] NOHZ: local_softirq_pending 02 [ 84.087904] NOHZ: local_softirq_pending 02 [ 84.088526] NOHZ: local_softirq_pending 02 [ 84.088899] NOHZ: local_softirq_pending 02 [ 84.089463] NOHZ: local_softirq_pending 02 [ 115.013470] NOHZ: local_softirq_pending 02 [ 115.013601] NOHZ: local_softirq_pending 02 [ 115.013709] NOHZ: local_softirq_pending 02 This was introduced during the timer-softirq split. Cc: stable-rt@vger.kernel.org Signed-off-by: Mike Galbraith Signed-off-by: Sebastian Andrzej Siewior --- kernel/softirq.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/kernel/softirq.c b/kernel/softirq.c index af0b78e44bb0..b5f185b89857 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -206,6 +206,7 @@ static void handle_softirq(unsigned int vec_nr) } } +#ifndef CONFIG_PREEMPT_RT_FULL /* * If ksoftirqd is scheduled, we do not want to process pending softirqs * right now. Let ksoftirqd handle this at its own rate, to get fairness, @@ -221,7 +222,6 @@ static bool ksoftirqd_running(unsigned long pending) return tsk && (tsk->state == TASK_RUNNING); } -#ifndef CONFIG_PREEMPT_RT_FULL static inline int ksoftirqd_softirq_pending(void) { return local_softirq_pending(); @@ -777,14 +777,10 @@ void irq_enter(void) static inline void invoke_softirq(void) { -#ifdef CONFIG_PREEMPT_RT_FULL - unsigned long flags; -#endif - +#ifndef CONFIG_PREEMPT_RT_FULL if (ksoftirqd_running(local_softirq_pending())) return; -#ifndef CONFIG_PREEMPT_RT_FULL if (!force_irqthreads) { #ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK /* @@ -805,6 +801,7 @@ static inline void invoke_softirq(void) wakeup_softirqd(); } #else /* PREEMPT_RT_FULL */ + unsigned long flags; local_irq_save(flags); if (__this_cpu_read(ksoftirqd) && -- 2.28.0