When selecting PREEMPT_RT, cpufreq_driver->stop_cpu(policy) might get stuck due to irq_work_sync() pending for work on lazy_list, which had no chance to be served in softirq context sometimes. The reason of lazy_list was not served is because the nearest activated timer might have been set to expire after long time (such as 100+ seconds). Then function run_local_timers() would not call raise_softirq(TIMER_SOFTIRQ) to handle enqueued irq_work. This is observed on LX2160ARDB and LS1088ARDB with cpufreq governor of ‘schedutil’ or ‘ondemand’. Configure related irqwork to run on raw-irq context could fix this issue. Signed-off-by: Ran Wang <ran.wang_1@xxxxxxx> --- Change in v2: - Update commit message to explain root cause more clear. drivers/cpufreq/cpufreq_governor.c | 2 +- kernel/sched/cpufreq_schedutil.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index 63f7c219062b..731a7b1434df 100644 --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -360,7 +360,7 @@ static struct policy_dbs_info *alloc_policy_dbs_info(struct cpufreq_policy *poli policy_dbs->policy = policy; mutex_init(&policy_dbs->update_mutex); atomic_set(&policy_dbs->work_count, 0); - init_irq_work(&policy_dbs->irq_work, dbs_irq_work); + policy_dbs->irq_work = IRQ_WORK_INIT_HARD(dbs_irq_work); INIT_WORK(&policy_dbs->work, dbs_work_handler); /* Set policy_dbs for all CPUs, online+offline */ diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 50cbad89f7fa..1d5af87ec92e 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -611,7 +611,7 @@ static int sugov_kthread_create(struct sugov_policy *sg_policy) sg_policy->thread = thread; kthread_bind_mask(thread, policy->related_cpus); - init_irq_work(&sg_policy->irq_work, sugov_irq_work); + sg_policy->irq_work = IRQ_WORK_INIT_HARD(sugov_irq_work); mutex_init(&sg_policy->work_lock); wake_up_process(thread); -- 2.25.1
