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-rw-r--r--drivers/cpufreq/cpufreq.c6
-rw-r--r--include/linux/cpufreq.h9
2 files changed, 15 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 96f1a8860819..5ca8e9517aae 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -154,6 +154,12 @@ bool have_governor_per_policy(void)
}
EXPORT_SYMBOL_GPL(have_governor_per_policy);
+bool cpufreq_driver_is_slow(void)
+{
+ return !(cpufreq_driver->flags & CPUFREQ_DRIVER_FAST);
+}
+EXPORT_SYMBOL_GPL(cpufreq_driver_is_slow);
+
struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
{
if (have_governor_per_policy())
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 9b1d61e1f1d7..b5ef79aae048 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -160,6 +160,7 @@ u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy);
int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
int cpufreq_update_policy(unsigned int cpu);
bool have_governor_per_policy(void);
+bool cpufreq_driver_is_slow(void);
struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy);
#else
static inline unsigned int cpufreq_get(unsigned int cpu)
@@ -317,6 +318,14 @@ struct cpufreq_driver {
*/
#define CPUFREQ_NEED_INITIAL_FREQ_CHECK (1 << 5)
+/*
+ * Indicates that it is safe to call cpufreq_driver_target from
+ * non-interruptable context in scheduler hot paths. Drivers must
+ * opt-in to this flag, as the safe default is that they might sleep
+ * or be too slow for hot path use.
+ */
+#define CPUFREQ_DRIVER_FAST (1 << 6)
+
int cpufreq_register_driver(struct cpufreq_driver *driver_data);
int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);