The EAS topology code requires the usage of schedutil on all CPUs of an
rd to actually enable EAS balancing. However, the check implementing
this references the schedutil_gov struct directly, which makes having
schedutil as a module impractical.
To prepare the ground for this modularization, introduce a new
'want_eas' flag in the cpufreq_governor struct, set it for schedutil
only, and make sure to check it from the EAS topology code.
Signed-off-by: Quentin Perret <qper...@google.com>
---
include/linux/cpufreq.h | 4 ++++
kernel/sched/cpufreq_schedutil.c | 5 ++++-
kernel/sched/topology.c | 12 ++++++------
3 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index f7240251a949..267cc3b624da 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -560,6 +560,10 @@ struct cpufreq_governor {
bool dynamic_switching;
struct list_head governor_list;
struct module *owner;
+
+#ifdef CONFIG_ENERGY_MODEL
+ bool want_eas;
+#endif /* CONFIG_ENERGY_MODEL */
};
/* Pass a target to the cpufreq driver */
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index ebd5d30f0861..c5e5045f7c81 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -888,6 +888,9 @@ struct cpufreq_governor schedutil_gov = {
.start = sugov_start,
.stop = sugov_stop,
.limits = sugov_limits,
+#ifdef CONFIG_ENERGY_MODEL
+ .want_eas = true,
+#endif /* CONFIG_ENERGY_MODEL */
};
#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL
@@ -924,7 +927,7 @@ static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn);
void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
struct cpufreq_governor *old_gov)
{
- if (old_gov == &schedutil_gov || policy->governor == &schedutil_gov) {
+ if ((old_gov && old_gov->want_eas) || policy->governor->want_eas) {
/*
* When called from the cpufreq_register_driver() path, the
* cpu_hotplug_lock is already held, so use a work item to
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 8344757bba6e..b905f2e8d9b2 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -319,7 +319,8 @@ static void sched_energy_set(bool has_eas)
* 2. the SD_ASYM_CPUCAPACITY flag is set in the sched_domain hierarchy.
* 3. no SMT is detected.
* 4. the EM complexity is low enough to keep scheduling overheads low;
- * 5. schedutil is driving the frequency of all CPUs of the rd;
+ * 5. an EAS-compatible CPUfreq governor (schedutil) is driving the
frequency
+ * of all CPUs of the rd;
*
* The complexity of the Energy Model is defined as:
*
@@ -339,7 +340,6 @@ static void sched_energy_set(bool has_eas)
*/
#define EM_MAX_COMPLEXITY 2048
-extern struct cpufreq_governor schedutil_gov;
static bool build_perf_domains(const struct cpumask *cpu_map)
{
int i, nr_pd = 0, nr_cs = 0, nr_cpus = cpumask_weight(cpu_map);
@@ -347,7 +347,7 @@ static bool build_perf_domains(const struct cpumask
*cpu_map)
int cpu = cpumask_first(cpu_map);
struct root_domain *rd = cpu_rq(cpu)->rd;
struct cpufreq_policy *policy;
- struct cpufreq_governor *gov;
+ bool want_eas;
if (!sysctl_sched_energy_aware)
goto free;
@@ -377,11 +377,11 @@ static bool build_perf_domains(const struct cpumask
*cpu_map)
policy = cpufreq_cpu_get(i);
if (!policy)
goto free;
- gov = policy->governor;
+ want_eas = policy->governor && policy->governor->want_eas;
cpufreq_cpu_put(policy);
- if (gov != &schedutil_gov) {
+ if (!want_eas) {
if (rd->pd)
- pr_warn("rd %*pbl: Disabling EAS, schedutil is
mandatory\n",
+ pr_warn("rd %*pbl: Disabling EAS because of
incompatible CPUFreq governor\n",
cpumask_pr_args(cpu_map));
goto free;
}
--
2.26.2.526.g744177e7f7-goog
