Merge "cpufreq: interactive: Re-evaluate immediately in load change callback" (6d6293bc) · Commits · e / devices / android_kernel_sony_msm8994

drivers/cpufreq/cpufreq_interactive.c

+22 −33

Original line number	Diff line number	Diff line
		@@ -170,25 +170,6 @@ static inline int set_window_helper(
		usecs_to_jiffies(tunables->timer_rate));
		}

		/*
		* Scheduler holds various locks when sending load change notification.
		* Attempting to wake up a thread or schedule a work could result in a
		* deadlock. Therefore we schedule the timer to fire immediately.
		* Since we are just re-evaluating previous window's load, we
		* should not push back slack timer.
		*/
		static void cpufreq_interactive_timer_resched_now(unsigned long cpu)
		{
		unsigned long flags;
		struct cpufreq_interactive_cpuinfo *pcpu = &per_cpu(cpuinfo, cpu);

		spin_lock_irqsave(&pcpu->load_lock, flags);
		del_timer(&pcpu->cpu_timer);
		pcpu->cpu_timer.expires = jiffies;
		add_timer_on(&pcpu->cpu_timer, cpu);
		spin_unlock_irqrestore(&pcpu->load_lock, flags);
		}

		static void cpufreq_interactive_timer_resched(unsigned long cpu)
		{
		struct cpufreq_interactive_cpuinfo *pcpu = &per_cpu(cpuinfo, cpu);
		@@ -431,10 +412,9 @@ static void cpufreq_interactive_timer(unsigned long data)
		/*
		* Unlock early to avoid deadlock.
		*
		* cpufreq_interactive_timer_resched_now() is called
		* in thread migration notification which already holds
		* rq lock. Then it locks load_lock to avoid racing with
		* cpufreq_interactive_timer_resched/start().
		* load_change_callback() for thread migration already
		* holds rq lock. Then it locks load_lock to avoid racing
		* with cpufreq_interactive_timer_resched/start().
		* sched_get_busy() will also acquire rq lock. Thus we
		* can't hold load_lock when calling sched_get_busy().
		*
		@@ -752,18 +732,27 @@ static int load_change_callback(struct notifier_block *nb, unsigned long val,
		struct cpufreq_interactive_cpuinfo *pcpu = &per_cpu(cpuinfo, cpu);
		struct cpufreq_interactive_tunables *tunables;

		/*
		* We can't acquire enable_sem here. However, this doesn't matter
		* because timer function will grab it and check if governor is
		* enabled before doing anything. Therefore the execution is
		* still correct.
		*/
		if (pcpu->governor_enabled) {
		tunables = per_cpu(cpuinfo, pcpu->first_cpu).cached_tunables;
		if (tunables->use_sched_load && tunables->use_migration_notif)
		cpufreq_interactive_timer_resched_now(cpu);
		if (speedchange_task == current)
		return 0;

		if (!down_read_trylock(&pcpu->enable_sem))
		return 0;
		if (!pcpu->governor_enabled) {
		up_read(&pcpu->enable_sem);
		return 0;
		}
		tunables = pcpu->policy->governor_data;
		if (!tunables->use_sched_load \|\| !tunables->use_migration_notif) {
		up_read(&pcpu->enable_sem);
		return 0;
		}

		trace_cpufreq_interactive_load_change(cpu);
		del_timer(&pcpu->cpu_timer);
		del_timer(&pcpu->cpu_slack_timer);
		cpufreq_interactive_timer(cpu);

		up_read(&pcpu->enable_sem);
		return 0;
		}

include/trace/events/cpufreq_interactive.h

+12 −0

Original line number	Diff line number	Diff line
		@@ -106,6 +106,18 @@ TRACE_EVENT(cpufreq_interactive_unboost,
		TP_printk("%s", __get_str(s))
		);

		TRACE_EVENT(cpufreq_interactive_load_change,
		TP_PROTO(unsigned long cpu_id),
		TP_ARGS(cpu_id),
		TP_STRUCT__entry(
		__field(unsigned long, cpu_id)
		),
		TP_fast_assign(
		__entry->cpu_id = cpu_id;
		),
		TP_printk("re-evaluate for cpu=%lu", __entry->cpu_id)
		);

		#endif /* _TRACE_CPUFREQ_INTERACTIVE_H */

		/* This part must be outside protection */