Commit 9591becb authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki
Browse files

cpufreq: Restart governor as soon as possible 



__cpufreq_remove_dev_finish() is doing two things today:
- Restarts the governor if some CPUs from concerned policy are still
  online.
- Frees the policy if all CPUs are offline.

The first task of restarting the governor can be moved to
__cpufreq_remove_dev_prepare() to restart the governor early. There is
no race between _prepare() and _finish() as they would be handling
completely different cases. _finish() will only be required if we are
going to free the policy and that has nothing to do with restarting the
governor.

Original-by: default avatarSaravana Kannan <skannan@codeaurora.org>
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 3654c5cc

drivers/cpufreq/cpufreq.c

+26 −33
Original line number Diff line number Diff line
@@ -1428,8 +1428,8 @@ nomem_out: 
static int __cpufreq_remove_dev_prepare(struct device *dev,

					struct subsys_interface *sif)

{

	unsigned int cpu = dev->id, cpus;

	int ret;

	unsigned int cpu = dev->id;

	int ret = 0;

	struct cpufreq_policy *policy;



	pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
@@ -1449,23 +1449,33 @@ static int __cpufreq_remove_dev_prepare(struct device *dev, 
	}



	down_write(&policy->rwsem);

	cpus = cpumask_weight(policy->cpus);

	cpumask_clear_cpu(cpu, policy->cpus);



	if (has_target() && cpus == 1)

	if (policy_is_inactive(policy)) {

		if (has_target())

			strncpy(policy->last_governor, policy->governor->name,

				CPUFREQ_NAME_LEN);

	} else if (cpu == policy->cpu) {

		/* Nominate new CPU */

		policy->cpu = cpumask_any(policy->cpus);

	}

	up_write(&policy->rwsem);



	if (cpu != policy->cpu)

		return 0;

	/* Start governor again for active policy */

	if (!policy_is_inactive(policy)) {

		if (has_target()) {

			ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);

			if (!ret)

				ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);



	if (cpus > 1)

		/* Nominate new CPU */

		update_policy_cpu(policy, cpumask_any_but(policy->cpus, cpu));

	else if (cpufreq_driver->stop_cpu)

			if (ret)

				pr_err("%s: Failed to start governor\n", __func__);

		}

	} else if (cpufreq_driver->stop_cpu) {

		cpufreq_driver->stop_cpu(policy);

	}



	return 0;

	return ret;

}



static int __cpufreq_remove_dev_finish(struct device *dev,
@@ -1473,34 +1483,17 @@ static int __cpufreq_remove_dev_finish(struct device *dev, 
{

	unsigned int cpu = dev->id;

	int ret;

	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);

	struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);



	if (!policy) {

		pr_debug("%s: No cpu_data found\n", __func__);

		return -EINVAL;

	}



	down_write(&policy->rwsem);

	cpumask_clear_cpu(cpu, policy->cpus);

	up_write(&policy->rwsem);



	/* Not the last cpu of policy, start governor again ? */

	if (!policy_is_inactive(policy)) {

		if (!has_target())

	/* Only proceed for inactive policies */

	if (!policy_is_inactive(policy))

		return 0;



		ret = __cpufreq_governor(policy, CPUFREQ_GOV_START);

		if (!ret)

			ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);



		if (ret) {

			pr_err("%s: Failed to start governor\n", __func__);

			return ret;

		}



		return 0;

	}



	/* If cpu is last user of policy, free policy */

	if (has_target()) {

		ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);

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