cpufreq: governor: Replace timers with utilization update callbacks

Instead of using a per-CPU deferrable timer for queuing up governor
work items, register a utilization update callback that will be
invoked from the scheduler on utilization changes.

The sampling rate is still the same as what was used for the
deferrable timers and the added irq_work overhead should be offset by
the eliminated timers overhead, so in theory the functional impact of
this patch should not be significant.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c
index 8504a70a4785..bc002c8cba90 100644
--- a/drivers/cpufreq/cpufreq_conservative.c
+++ b/drivers/cpufreq/cpufreq_conservative.c
@@ -112,14 +112,12 @@ static void cs_check_cpu(int cpu, unsigned int load)
 	}
 }
 
-static unsigned int cs_dbs_timer(struct cpufreq_policy *policy, bool modify_all)
+static unsigned int cs_dbs_timer(struct cpufreq_policy *policy)
 {
 	struct dbs_data *dbs_data = policy->governor_data;
 	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
 
-	if (modify_all)
-		dbs_check_cpu(dbs_data, policy->cpu);
-
+	dbs_check_cpu(dbs_data, policy->cpu);
 	return delay_for_sampling_rate(cs_tuners->sampling_rate);
 }