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-rw-r--r--kernel/sched/cpufreq_schedutil.c31
1 files changed, 23 insertions, 8 deletions
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 758efd7f3abe..a84641b222c1 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -47,6 +47,8 @@ struct sugov_cpu {
struct update_util_data update_util;
struct sugov_policy *sg_policy;
+ unsigned int cached_raw_freq;
+
/* The fields below are only needed when sharing a policy. */
unsigned long util;
unsigned long max;
@@ -106,7 +108,7 @@ static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time,
/**
* get_next_freq - Compute a new frequency for a given cpufreq policy.
- * @policy: cpufreq policy object to compute the new frequency for.
+ * @sg_cpu: schedutil cpu object to compute the new frequency for.
* @util: Current CPU utilization.
* @max: CPU capacity.
*
@@ -121,14 +123,25 @@ static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time,
* next_freq = C * curr_freq * util_raw / max
*
* Take C = 1.25 for the frequency tipping point at (util / max) = 0.8.
+ *
+ * The lowest driver-supported frequency which is equal or greater than the raw
+ * next_freq (as calculated above) is returned, subject to policy min/max and
+ * cpufreq driver limitations.
*/
-static unsigned int get_next_freq(struct cpufreq_policy *policy,
- unsigned long util, unsigned long max)
+static unsigned int get_next_freq(struct sugov_cpu *sg_cpu, unsigned long util,
+ unsigned long max)
{
+ struct sugov_policy *sg_policy = sg_cpu->sg_policy;
+ struct cpufreq_policy *policy = sg_policy->policy;
unsigned int freq = arch_scale_freq_invariant() ?
policy->cpuinfo.max_freq : policy->cur;
- return (freq + (freq >> 2)) * util / max;
+ freq = (freq + (freq >> 2)) * util / max;
+
+ if (freq == sg_cpu->cached_raw_freq && sg_policy->next_freq != UINT_MAX)
+ return sg_policy->next_freq;
+ sg_cpu->cached_raw_freq = freq;
+ return cpufreq_driver_resolve_freq(policy, freq);
}
static void sugov_update_single(struct update_util_data *hook, u64 time,
@@ -143,13 +156,14 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
return;
next_f = util == ULONG_MAX ? policy->cpuinfo.max_freq :
- get_next_freq(policy, util, max);
+ get_next_freq(sg_cpu, util, max);
sugov_update_commit(sg_policy, time, next_f);
}
-static unsigned int sugov_next_freq_shared(struct sugov_policy *sg_policy,
+static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu,
unsigned long util, unsigned long max)
{
+ struct sugov_policy *sg_policy = sg_cpu->sg_policy;
struct cpufreq_policy *policy = sg_policy->policy;
unsigned int max_f = policy->cpuinfo.max_freq;
u64 last_freq_update_time = sg_policy->last_freq_update_time;
@@ -189,7 +203,7 @@ static unsigned int sugov_next_freq_shared(struct sugov_policy *sg_policy,
}
}
- return get_next_freq(policy, util, max);
+ return get_next_freq(sg_cpu, util, max);
}
static void sugov_update_shared(struct update_util_data *hook, u64 time,
@@ -206,7 +220,7 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
sg_cpu->last_update = time;
if (sugov_should_update_freq(sg_policy, time)) {
- next_f = sugov_next_freq_shared(sg_policy, util, max);
+ next_f = sugov_next_freq_shared(sg_cpu, util, max);
sugov_update_commit(sg_policy, time, next_f);
}
@@ -433,6 +447,7 @@ static int sugov_start(struct cpufreq_policy *policy)
sg_cpu->util = ULONG_MAX;
sg_cpu->max = 0;
sg_cpu->last_update = 0;
+ sg_cpu->cached_raw_freq = 0;
cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util,
sugov_update_shared);
} else {