}
EXPORT_SYMBOL(__local_bh_enable_ip);
+void softirq_preempt(void)
+{
+ if (WARN_ON_ONCE(!preemptible()))
+ return;
+
+ if (WARN_ON_ONCE(__this_cpu_read(softirq_ctrl.cnt) != SOFTIRQ_OFFSET))
+ return;
+
+ __local_bh_enable(SOFTIRQ_OFFSET, true);
+ /* preemption point */
+ __local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
+}
+
/*
* Invoked from ksoftirqd_run() outside of the interrupt disabled section
* to acquire the per CPU local lock for reentrancy protection.
#endif
}
+#ifdef CONFIG_PREEMPT_RT
+DEFINE_PER_CPU(struct task_struct *, timersd);
+DEFINE_PER_CPU(unsigned long, pending_timer_softirq);
+
+static void wake_timersd(void)
+{
+ struct task_struct *tsk = __this_cpu_read(timersd);
+
+ if (tsk)
+ wake_up_process(tsk);
+}
+
+#else
+
+static inline void wake_timersd(void) { }
+
+#endif
+
static inline void __irq_exit_rcu(void)
{
#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED
if (!in_interrupt() && local_softirq_pending())
invoke_softirq();
+ if (IS_ENABLED(CONFIG_PREEMPT_RT) && local_pending_timers() &&
+ !(in_nmi() | in_hardirq()))
+ wake_timersd();
+
tick_irq_exit();
}
.thread_comm = "ksoftirqd/%u",
};
+#ifdef CONFIG_PREEMPT_RT
+static void timersd_setup(unsigned int cpu)
+{
+ sched_set_fifo_low(current);
+}
+
+static int timersd_should_run(unsigned int cpu)
+{
+ return local_pending_timers();
+}
+
+static void run_timersd(unsigned int cpu)
+{
+ unsigned int timer_si;
+
+ ksoftirqd_run_begin();
+
+ timer_si = local_pending_timers();
+ __this_cpu_write(pending_timer_softirq, 0);
+ or_softirq_pending(timer_si);
+
+ __do_softirq();
+
+ ksoftirqd_run_end();
+}
+
+static void raise_ktimers_thread(unsigned int nr)
+{
+ trace_softirq_raise(nr);
+ __this_cpu_or(pending_timer_softirq, 1 << nr);
+}
+
+void raise_hrtimer_softirq(void)
+{
+ raise_ktimers_thread(HRTIMER_SOFTIRQ);
+}
+
+void raise_timer_softirq(void)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ raise_ktimers_thread(TIMER_SOFTIRQ);
+ wake_timersd();
+ local_irq_restore(flags);
+}
+
+static struct smp_hotplug_thread timer_threads = {
+ .store = &timersd,
+ .setup = timersd_setup,
+ .thread_should_run = timersd_should_run,
+ .thread_fn = run_timersd,
+ .thread_comm = "ktimers/%u",
+};
+#endif
+
static __init int spawn_ksoftirqd(void)
{
cpuhp_setup_state_nocalls(CPUHP_SOFTIRQ_DEAD, "softirq:dead", NULL,
takeover_tasklets);
BUG_ON(smpboot_register_percpu_thread(&softirq_threads));
-
+#ifdef CONFIG_PREEMPT_RT
+ BUG_ON(smpboot_register_percpu_thread(&timer_threads));
+#endif
return 0;
}
early_initcall(spawn_ksoftirqd);