Doing cpufreq-specific EAS checks that require accessing policy
internals directly from sched_is_eas_possible() is a bit unfortunate,
so introduce cpufreq_ready_for_eas() in cpufreq, move those checks
into that new function and make sched_is_eas_possible() call it.
While at it, address a possible race between the EAS governor check
and governor change by doing the former under the policy rwsem.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Christian Loehle <christian.loehle@arm.com>
Tested-by: Christian Loehle <christian.loehle@arm.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://patch.msgid.link/2317800.iZASKD2KPV@rjwysocki.net
return 0;
}
+
+static bool cpufreq_policy_is_good_for_eas(unsigned int cpu)
+{
+ struct cpufreq_policy *policy __free(put_cpufreq_policy);
+
+ policy = cpufreq_cpu_get(cpu);
+ if (!policy) {
+ pr_debug("cpufreq policy not set for CPU: %d\n", cpu);
+ return false;
+ }
+
+ guard(cpufreq_policy_read)(policy);
+
+ return sugov_is_governor(policy);
+}
+
+bool cpufreq_ready_for_eas(const struct cpumask *cpu_mask)
+{
+ unsigned int cpu;
+
+ /* Do not attempt EAS if schedutil is not being used. */
+ for_each_cpu(cpu, cpu_mask) {
+ if (!cpufreq_policy_is_good_for_eas(cpu)) {
+ pr_debug("rd %*pbl: schedutil is mandatory for EAS\n",
+ cpumask_pr_args(cpu_mask));
+ return false;
+ }
+ }
+
+ return true;
+}
+
module_param(off, int, 0444);
module_param_string(default_governor, default_governor, CPUFREQ_NAME_LEN, 0444);
core_initcall(cpufreq_core_init);
struct cpufreq_frequency_table *table,
unsigned int transition_latency);
+bool cpufreq_ready_for_eas(const struct cpumask *cpu_mask);
+
static inline void cpufreq_register_em_with_opp(struct cpufreq_policy *policy)
{
dev_pm_opp_of_register_em(get_cpu_device(policy->cpu),
static bool sched_is_eas_possible(const struct cpumask *cpu_mask)
{
bool any_asym_capacity = false;
- struct cpufreq_policy *policy;
- bool policy_is_ready;
int i;
/* EAS is enabled for asymmetric CPU capacity topologies. */
return false;
}
- /* Do not attempt EAS if schedutil is not being used. */
- for_each_cpu(i, cpu_mask) {
- policy = cpufreq_cpu_get(i);
- if (!policy) {
- if (sched_debug()) {
- pr_info("rd %*pbl: Checking EAS, cpufreq policy not set for CPU: %d",
- cpumask_pr_args(cpu_mask), i);
- }
- return false;
- }
- policy_is_ready = sugov_is_governor(policy);
- cpufreq_cpu_put(policy);
- if (!policy_is_ready) {
- if (sched_debug()) {
- pr_info("rd %*pbl: Checking EAS, schedutil is mandatory\n",
- cpumask_pr_args(cpu_mask));
- }
- return false;
+ if (!cpufreq_ready_for_eas(cpu_mask)) {
+ if (sched_debug()) {
+ pr_info("rd %*pbl: Checking EAS: cpufreq is not ready\n",
+ cpumask_pr_args(cpu_mask));
}
+ return false;
}
return true;