On 30-03-21, 11:15, Ran Wang wrote: > 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); Will this have any impact on the non-preempt-rt case ? Otherwise, Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx> -- viresh
