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cpufreq: Add QoS requests for userspace constraints
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This implements QoS requests to manage userspace configuration of min
and max frequency.

Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: syzbot <syzbot+de771ae9390dffed7266@syzkaller.appspotmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Viresh Kumar authored and Rafael J. Wysocki committed Jul 8, 2019
1 parent c57b25b commit 18c4992
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Showing 2 changed files with 57 additions and 49 deletions.
98 changes: 55 additions & 43 deletions drivers/cpufreq/cpufreq.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -718,23 +718,15 @@ static ssize_t show_scaling_cur_freq(struct cpufreq_policy *policy, char *buf)
static ssize_t store_##file_name \
(struct cpufreq_policy *policy, const char *buf, size_t count) \
{ \
int ret, temp; \
struct cpufreq_policy new_policy; \
unsigned long val; \
int ret; \
\
memcpy(&new_policy, policy, sizeof(*policy)); \
new_policy.min = policy->user_policy.min; \
new_policy.max = policy->user_policy.max; \
\
ret = sscanf(buf, "%u", &new_policy.object); \
ret = sscanf(buf, "%lu", &val); \
if (ret != 1) \
return -EINVAL; \
\
temp = new_policy.object; \
ret = cpufreq_set_policy(policy, &new_policy); \
if (!ret) \
policy->user_policy.object = temp; \
\
return ret ? ret : count; \
ret = dev_pm_qos_update_request(policy->object##_freq_req, val);\
return ret >= 0 ? count : ret; \
}

store_one(scaling_min_freq, min);
Expand Down Expand Up @@ -1124,8 +1116,6 @@ void refresh_frequency_limits(struct cpufreq_policy *policy)
new_policy = *policy;
pr_debug("updating policy for CPU %u\n", policy->cpu);

new_policy.min = policy->user_policy.min;
new_policy.max = policy->user_policy.max;
cpufreq_set_policy(policy, &new_policy);
}
}
Expand Down Expand Up @@ -1281,6 +1271,9 @@ static void cpufreq_policy_free(struct cpufreq_policy *policy)
DEV_PM_QOS_MAX_FREQUENCY);
dev_pm_qos_remove_notifier(dev, &policy->nb_min,
DEV_PM_QOS_MIN_FREQUENCY);
dev_pm_qos_remove_request(policy->max_freq_req);
dev_pm_qos_remove_request(policy->min_freq_req);
kfree(policy->min_freq_req);

cpufreq_policy_put_kobj(policy);
free_cpumask_var(policy->real_cpus);
Expand Down Expand Up @@ -1359,16 +1352,50 @@ static int cpufreq_online(unsigned int cpu)
cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);

if (new_policy) {
policy->user_policy.min = policy->min;
policy->user_policy.max = policy->max;
struct device *dev = get_cpu_device(cpu);

for_each_cpu(j, policy->related_cpus) {
per_cpu(cpufreq_cpu_data, j) = policy;
add_cpu_dev_symlink(policy, j);
}
} else {
policy->min = policy->user_policy.min;
policy->max = policy->user_policy.max;

policy->min_freq_req = kzalloc(2 * sizeof(*policy->min_freq_req),
GFP_KERNEL);
if (!policy->min_freq_req)
goto out_destroy_policy;

ret = dev_pm_qos_add_request(dev, policy->min_freq_req,
DEV_PM_QOS_MIN_FREQUENCY,
policy->min);
if (ret < 0) {
/*
* So we don't call dev_pm_qos_remove_request() for an
* uninitialized request.
*/
kfree(policy->min_freq_req);
policy->min_freq_req = NULL;

dev_err(dev, "Failed to add min-freq constraint (%d)\n",
ret);
goto out_destroy_policy;
}

/*
* This must be initialized right here to avoid calling
* dev_pm_qos_remove_request() on uninitialized request in case
* of errors.
*/
policy->max_freq_req = policy->min_freq_req + 1;

ret = dev_pm_qos_add_request(dev, policy->max_freq_req,
DEV_PM_QOS_MAX_FREQUENCY,
policy->max);
if (ret < 0) {
policy->max_freq_req = NULL;
dev_err(dev, "Failed to add max-freq constraint (%d)\n",
ret);
goto out_destroy_policy;
}
}

if (cpufreq_driver->get && has_target()) {
Expand Down Expand Up @@ -2342,32 +2369,19 @@ int cpufreq_set_policy(struct cpufreq_policy *policy,
{
struct cpufreq_governor *old_gov;
struct device *cpu_dev = get_cpu_device(policy->cpu);
unsigned long min, max;
int ret;

pr_debug("setting new policy for CPU %u: %u - %u kHz\n",
new_policy->cpu, new_policy->min, new_policy->max);

memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));

/*
* This check works well when we store new min/max freq attributes,
* because new_policy is a copy of policy with one field updated.
*/
if (new_policy->min > new_policy->max)
return -EINVAL;

/*
* PM QoS framework collects all the requests from users and provide us
* the final aggregated value here.
*/
min = dev_pm_qos_read_value(cpu_dev, DEV_PM_QOS_MIN_FREQUENCY);
max = dev_pm_qos_read_value(cpu_dev, DEV_PM_QOS_MAX_FREQUENCY);

if (min > new_policy->min)
new_policy->min = min;
if (max < new_policy->max)
new_policy->max = max;
new_policy->min = dev_pm_qos_read_value(cpu_dev, DEV_PM_QOS_MIN_FREQUENCY);
new_policy->max = dev_pm_qos_read_value(cpu_dev, DEV_PM_QOS_MAX_FREQUENCY);

/* verify the cpu speed can be set within this limit */
ret = cpufreq_driver->verify(new_policy);
Expand Down Expand Up @@ -2456,10 +2470,9 @@ int cpufreq_set_policy(struct cpufreq_policy *policy,
* @cpu: CPU to re-evaluate the policy for.
*
* Update the current frequency for the cpufreq policy of @cpu and use
* cpufreq_set_policy() to re-apply the min and max limits saved in the
* user_policy sub-structure of that policy, which triggers the evaluation
* of policy notifiers and the cpufreq driver's ->verify() callback for the
* policy in question, among other things.
* cpufreq_set_policy() to re-apply the min and max limits, which triggers the
* evaluation of policy notifiers and the cpufreq driver's ->verify() callback
* for the policy in question, among other things.
*/
void cpufreq_update_policy(unsigned int cpu)
{
Expand Down Expand Up @@ -2519,10 +2532,9 @@ static int cpufreq_boost_set_sw(int state)
break;
}

down_write(&policy->rwsem);
policy->user_policy.max = policy->max;
cpufreq_governor_limits(policy);
up_write(&policy->rwsem);
ret = dev_pm_qos_update_request(policy->max_freq_req, policy->max);
if (ret)
break;
}

return ret;
Expand Down
8 changes: 2 additions & 6 deletions include/linux/cpufreq.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -50,11 +50,6 @@ struct cpufreq_cpuinfo {
unsigned int transition_latency;
};

struct cpufreq_user_policy {
unsigned int min; /* in kHz */
unsigned int max; /* in kHz */
};

struct cpufreq_policy {
/* CPUs sharing clock, require sw coordination */
cpumask_var_t cpus; /* Online CPUs only */
Expand Down Expand Up @@ -84,7 +79,8 @@ struct cpufreq_policy {
struct work_struct update; /* if update_policy() needs to be
* called, but you're in IRQ context */

struct cpufreq_user_policy user_policy;
struct dev_pm_qos_request *min_freq_req;
struct dev_pm_qos_request *max_freq_req;
struct cpufreq_frequency_table *freq_table;
enum cpufreq_table_sorting freq_table_sorted;

Expand Down

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