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cpufreq: Restart governor as soon as possible

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__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: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Viresh Kumar 2015-06-10 02:20:23 +02:00 committed by Rafael J. Wysocki
parent 3654c5cc81
commit 9591becbf2
1 changed files with 26 additions and 33 deletions
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59
drivers/cpufreq/cpufreq.c
View file

@ -1428,8 +1428,8 @@ nomem_out:
static int __cpufreq_remove_dev_prepare(struct device *dev, static int __cpufreq_remove_dev_prepare(struct device *dev,
struct subsys_interface *sif) struct subsys_interface *sif)
{ {
unsigned int cpu = dev->id, cpus; unsigned int cpu = dev->id;
int ret; int ret = 0;
struct cpufreq_policy *policy; struct cpufreq_policy *policy;
pr_debug("%s: unregistering CPU %u\n", __func__, cpu); 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); 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)) {
strncpy(policy->last_governor, policy->governor->name, if (has_target())
CPUFREQ_NAME_LEN); 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); up_write(&policy->rwsem);
if (cpu != policy->cpu) /* Start governor again for active policy */
return 0; 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) if (ret)
/* Nominate new CPU */ pr_err("%s: Failed to start governor\n", __func__);
update_policy_cpu(policy, cpumask_any_but(policy->cpus, cpu)); }
else if (cpufreq_driver->stop_cpu) } else if (cpufreq_driver->stop_cpu) {
cpufreq_driver->stop_cpu(policy); cpufreq_driver->stop_cpu(policy);
}
return 0; return ret;
} }
static int __cpufreq_remove_dev_finish(struct device *dev, static int __cpufreq_remove_dev_finish(struct device *dev,
@ -1473,33 +1483,16 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
{ {
unsigned int cpu = dev->id; unsigned int cpu = dev->id;
int ret; int ret;
struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu); struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
if (!policy) { if (!policy) {
pr_debug("%s: No cpu_data found\n", __func__); pr_debug("%s: No cpu_data found\n", __func__);
return -EINVAL; return -EINVAL;
} }
down_write(&policy->rwsem); /* Only proceed for inactive policies */
cpumask_clear_cpu(cpu, policy->cpus); if (!policy_is_inactive(policy))
up_write(&policy->rwsem);
/* Not the last cpu of policy, start governor again ? */
if (!policy_is_inactive(policy)) {
if (!has_target())
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; return 0;
}
/* If cpu is last user of policy, free policy */ /* If cpu is last user of policy, free policy */
if (has_target()) { if (has_target()) {