From c7f652e0487a35c16f6cd72707232b6a28647a10 Mon Sep 17 00:00:00 2001
From: Venki Pallipadi <venkatesh.pallipadi@intel.com>
Date: Wed, 20 Jun 2007 14:24:00 -0700
Subject: [PATCH] [CPUFREQ] Keep userspace governor quiet when it is not being
used
Userspace governor registers a frequency change notifier at init time, even
when no CPU is set to userspace governor. Make it register only when
atleast one CPU is using userspace.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>
---
drivers/cpufreq/cpufreq_userspace.c | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/drivers/cpufreq/cpufreq_userspace.c b/drivers/cpufreq/cpufreq_userspace.c
index 860345c7799a..b1348ff9fcf4 100644
--- a/drivers/cpufreq/cpufreq_userspace.c
+++ b/drivers/cpufreq/cpufreq_userspace.c
@@ -37,6 +37,7 @@ static unsigned int cpu_set_freq[NR_CPUS]; /* CPU freq desired by userspace */
static unsigned int cpu_is_managed[NR_CPUS];
static DEFINE_MUTEX (userspace_mutex);
+static int cpus_using_userspace_governor;
#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_GOVERNOR, "userspace", msg)
@@ -47,7 +48,11 @@ userspace_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
{
struct cpufreq_freqs *freq = data;
- dprintk("saving cpu_cur_freq of cpu %u to be %u kHz\n", freq->cpu, freq->new);
+ if (!cpu_is_managed[freq->cpu])
+ return 0;
+
+ dprintk("saving cpu_cur_freq of cpu %u to be %u kHz\n",
+ freq->cpu, freq->new);
cpu_cur_freq[freq->cpu] = freq->new;
return 0;
@@ -142,6 +147,13 @@ static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
if (rc)
goto start_out;
+ if (cpus_using_userspace_governor == 0) {
+ cpufreq_register_notifier(
+ &userspace_cpufreq_notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
+ }
+ cpus_using_userspace_governor++;
+
cpu_is_managed[cpu] = 1;
cpu_min_freq[cpu] = policy->min;
cpu_max_freq[cpu] = policy->max;
@@ -153,6 +165,13 @@ start_out:
break;
case CPUFREQ_GOV_STOP:
mutex_lock(&userspace_mutex);
+ cpus_using_userspace_governor--;
+ if (cpus_using_userspace_governor == 0) {
+ cpufreq_unregister_notifier(
+ &userspace_cpufreq_notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
+ }
+
cpu_is_managed[cpu] = 0;
cpu_min_freq[cpu] = 0;
cpu_max_freq[cpu] = 0;
@@ -198,7 +217,6 @@ EXPORT_SYMBOL(cpufreq_gov_userspace);
static int __init cpufreq_gov_userspace_init(void)
{
- cpufreq_register_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
return cpufreq_register_governor(&cpufreq_gov_userspace);
}
@@ -206,7 +224,6 @@ static int __init cpufreq_gov_userspace_init(void)
static void __exit cpufreq_gov_userspace_exit(void)
{
cpufreq_unregister_governor(&cpufreq_gov_userspace);
- cpufreq_unregister_notifier(&userspace_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
}
--
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