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Commit 2cd7cc79 authored by Junjie Wu's avatar Junjie Wu
Browse files

cpufreq: interactive: Use del_timer/add_timer_on to rearm timers 



Replace mod_timer_pinned() with del_timer(), add_timer_on().
mod_timer_pinned() always adds timer onto current CPU. Interactive
governor expects each CPU's timers to be running on the same CPU.
If cpufreq_interactive_timer_resched() is called from another CPU,
the timer will be armed on the wrong CPU.

Replacing mod_timer_pinned() with del_timer() and add_timer_on()
guarantees timers are still run on the right CPU even if another
CPU reschedules the timer. This would provide more flexibility
for future changes.

Change-Id: I3a10be37632afc0ea4e0cc9c86323b9783b216b1
Signed-off-by: default avatarJunjie Wu <junjiew@codeaurora.org>
parent 53994155

drivers/cpufreq/cpufreq_interactive.c

+13 −9
Original line number Diff line number Diff line
@@ -133,9 +133,9 @@ static u64 round_to_nw_start(u64 jif, 
	return (jif + 1) * step;

}



static void cpufreq_interactive_timer_resched(

	struct cpufreq_interactive_cpuinfo *pcpu)

static void cpufreq_interactive_timer_resched(unsigned long cpu)

{

	struct cpufreq_interactive_cpuinfo *pcpu = &per_cpu(cpuinfo, cpu);

	struct cpufreq_interactive_tunables *tunables =

		pcpu->policy->governor_data;

	u64 expires;
@@ -149,12 +149,16 @@ static void cpufreq_interactive_timer_resched( 
	pcpu->cputime_speedadj = 0;

	pcpu->cputime_speedadj_timestamp = pcpu->time_in_idle_timestamp;

	expires = round_to_nw_start(pcpu->last_evaluated_jiffy, tunables);

	mod_timer_pinned(&pcpu->cpu_timer, expires);

	del_timer(&pcpu->cpu_timer);

	pcpu->cpu_timer.expires = expires;

	add_timer_on(&pcpu->cpu_timer, cpu);



	if (tunables->timer_slack_val >= 0 &&

	    pcpu->target_freq > pcpu->policy->min) {

		expires += usecs_to_jiffies(tunables->timer_slack_val);

		mod_timer_pinned(&pcpu->cpu_slack_timer, expires);

		del_timer(&pcpu->cpu_slack_timer);

		pcpu->cpu_slack_timer.expires = expires;

		add_timer_on(&pcpu->cpu_slack_timer, cpu);

	}



	spin_unlock_irqrestore(&pcpu->load_lock, flags);
@@ -171,6 +175,7 @@ static void cpufreq_interactive_timer_start( 
	u64 expires = round_to_nw_start(pcpu->last_evaluated_jiffy, tunables);

	unsigned long flags;



	spin_lock_irqsave(&pcpu->load_lock, flags);

	pcpu->cpu_timer.expires = expires;

	add_timer_on(&pcpu->cpu_timer, cpu);

	if (tunables->timer_slack_val >= 0 &&
@@ -180,7 +185,6 @@ static void cpufreq_interactive_timer_start( 
		add_timer_on(&pcpu->cpu_slack_timer, cpu);

	}



	spin_lock_irqsave(&pcpu->load_lock, flags);

	pcpu->time_in_idle =

		get_cpu_idle_time(cpu, &pcpu->time_in_idle_timestamp,

				  tunables->io_is_busy);
@@ -471,7 +475,7 @@ rearm_if_notmax: 


rearm:

	if (!timer_pending(&pcpu->cpu_timer))

		cpufreq_interactive_timer_resched(pcpu);

		cpufreq_interactive_timer_resched(data);



exit:

	up_read(&pcpu->enable_sem);
@@ -504,7 +508,7 @@ static void cpufreq_interactive_idle_start(void) 
		 */

		if (!pending) {

			pcpu->last_evaluated_jiffy = get_jiffies_64();

			cpufreq_interactive_timer_resched(pcpu);

			cpufreq_interactive_timer_resched(smp_processor_id());

		}

	}
@@ -525,7 +529,7 @@ static void cpufreq_interactive_idle_end(void) 


	/* Arm the timer for 1-2 ticks later if not already. */

	if (!timer_pending(&pcpu->cpu_timer)) {

		cpufreq_interactive_timer_resched(pcpu);

		cpufreq_interactive_timer_resched(smp_processor_id());

	} else if (time_after_eq(jiffies, pcpu->cpu_timer.expires)) {

		del_timer(&pcpu->cpu_timer);

		del_timer(&pcpu->cpu_slack_timer);
@@ -1358,7 +1362,7 @@ static int cpufreq_governor_interactive(struct cpufreq_policy *policy, 
				down_write(&pcpu->enable_sem);

				del_timer_sync(&pcpu->cpu_timer);

				del_timer_sync(&pcpu->cpu_slack_timer);

				cpufreq_interactive_timer_start(tunables, j);

				cpufreq_interactive_timer_resched(j);

				up_write(&pcpu->enable_sem);

			}