From: Lianwei Wang <a22...@motorola.com>
When the policy max freq is raised, and before the timer is
rescheduled in idle callback, the cpu freq may stuck at a
lower freq.
The target_freq shall be updated too, else on a high load
situation, the new_freq is always equal to target_freq and
which will cause freq stuck at a lower freq too.
Reschedule the timer on gov limits callback.
Change-Id: I6c187001ab43e859731429b64f75a74eebc37a24
Signed-off-by: Lianwei Wang <a22...@motorola.com>
Signed-off-by: Bálint Czobor <czoborbal...@gmail.com>
---
drivers/cpufreq/cpufreq_interactive.c | 64 +++++++++++++++++++++++++++------
1 file changed, 54 insertions(+), 10 deletions(-)
diff --git a/drivers/cpufreq/cpufreq_interactive.c
b/drivers/cpufreq/cpufreq_interactive.c
index 691923d..90958fd 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -189,6 +189,32 @@ static void cpufreq_interactive_timer_resched(
spin_unlock_irqrestore(&pcpu->load_lock, flags);
}
+/* The caller shall take enable_sem write semaphore to avoid any timer race.
+ * The cpu_timer and cpu_slack_timer must be deactivated when calling this
+ * function.
+ */
+static void cpufreq_interactive_timer_start(int cpu)
+{
+ struct cpufreq_interactive_cpuinfo *pcpu = &per_cpu(cpuinfo, cpu);
+ unsigned long expires = jiffies + usecs_to_jiffies(timer_rate);
+ unsigned long flags;
+
+ pcpu->cpu_timer.expires = expires;
+ add_timer_on(&pcpu->cpu_timer, cpu);
+ if (timer_slack_val >= 0 && pcpu->target_freq > pcpu->policy->min) {
+ expires += usecs_to_jiffies(timer_slack_val);
+ pcpu->cpu_slack_timer.expires = expires;
+ add_timer_on(&pcpu->cpu_slack_timer, cpu);
+ }
+
+ spin_lock_irqsave(&pcpu->load_lock, flags);
+ pcpu->time_in_idle =
+ get_cpu_idle_time(cpu, &pcpu->time_in_idle_timestamp);
+ pcpu->cputime_speedadj = 0;
+ pcpu->cputime_speedadj_timestamp = pcpu->time_in_idle_timestamp;
+ spin_unlock_irqrestore(&pcpu->load_lock, flags);
+}
+
static unsigned int freq_to_above_hispeed_delay(unsigned int freq)
{
int i;
@@ -1058,8 +1084,6 @@ static int cpufreq_governor_interactive(struct
cpufreq_policy *policy,
hispeed_freq = policy->max;
for_each_cpu(j, policy->cpus) {
- unsigned long expires;
-
pcpu = &per_cpu(cpuinfo, j);
pcpu->policy = policy;
pcpu->target_freq = policy->cur;
@@ -1070,14 +1094,7 @@ static int cpufreq_governor_interactive(struct
cpufreq_policy *policy,
pcpu->hispeed_validate_time =
pcpu->floor_validate_time;
down_write(&pcpu->enable_sem);
- expires = jiffies + usecs_to_jiffies(timer_rate);
- pcpu->cpu_timer.expires = expires;
- add_timer_on(&pcpu->cpu_timer, j);
- if (timer_slack_val >= 0) {
- expires += usecs_to_jiffies(timer_slack_val);
- pcpu->cpu_slack_timer.expires = expires;
- add_timer_on(&pcpu->cpu_slack_timer, j);
- }
+ cpufreq_interactive_timer_start(j);
pcpu->governor_enabled = 1;
up_write(&pcpu->enable_sem);
}
@@ -1136,6 +1153,33 @@ static int cpufreq_governor_interactive(struct
cpufreq_policy *policy,
else if (policy->min > policy->cur)
__cpufreq_driver_target(policy,
policy->min, CPUFREQ_RELATION_L);
+ for_each_cpu(j, policy->cpus) {
+ pcpu = &per_cpu(cpuinfo, j);
+
+ /* hold write semaphore to avoid race */
+ down_write(&pcpu->enable_sem);
+ if (pcpu->governor_enabled == 0) {
+ up_write(&pcpu->enable_sem);
+ continue;
+ }
+
+ /* update target_freq firstly */
+ if (policy->max < pcpu->target_freq)
+ pcpu->target_freq = policy->max;
+ else if (policy->min > pcpu->target_freq)
+ pcpu->target_freq = policy->min;
+
+ /* Reschedule timer.
+ * Delete the timers, else the timer callback may
+ * return without re-arm the timer when failed
+ * acquire the semaphore. This race may cause timer
+ * stopped unexpectedly.
+ */
+ del_timer_sync(&pcpu->cpu_timer);
+ del_timer_sync(&pcpu->cpu_slack_timer);
+ cpufreq_interactive_timer_start(j);
+ up_write(&pcpu->enable_sem);
+ }
break;
}
return 0;
--
1.7.9.5
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