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[CPUFREQ] Cleanup locking in conservative governor 

Redesign the locking inside conservative driver. Make dbs_mutex handle all the
global state changes inside the driver and invent a new percpu mutex
to serialize percpu timer and frequency limit change.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>
This commit is contained in:
venkatesh.pallipadi@intel.com 2009-07-02 17:08:33 -07:00 committed by Dave Jones
parent 5a75c82828
commit ee88415caf
1 changed files with 13 additions and 21 deletions
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34
drivers/cpufreq/cpufreq_conservative.c
View File

@ -63,7 +63,12 @@ struct cpu_dbs_info_s {
unsigned int down_skip;
unsigned int requested_freq;
int cpu;
unsigned int enable:1;
/*
* percpu mutex that serializes governor limit change with
* do_dbs_timer invocation. We do not want do_dbs_timer to run
* when user is changing the governor or limits.
*/
struct mutex timer_mutex;
};
static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
@ -71,9 +76,7 @@ static unsigned int dbs_enable; /* number of CPUs using this policy */
/*
* dbs_mutex protects data in dbs_tuners_ins from concurrent changes on
* different CPUs. It protects dbs_enable in governor start/stop. It also
* serializes governor limit_change with do_dbs_timer. We do not want
* do_dbs_timer to run when user is changing the governor or limits.
* different CPUs. It protects dbs_enable in governor start/stop.
*/
static DEFINE_MUTEX(dbs_mutex);
@ -138,9 +141,6 @@ dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
struct cpufreq_policy *policy;
if (!this_dbs_info->enable)
return 0;
policy = this_dbs_info->cur_policy;
/*
@ -483,17 +483,12 @@ static void do_dbs_timer(struct work_struct *work)
delay -= jiffies % delay;
mutex_lock(&dbs_mutex);
if (!dbs_info->enable) {
mutex_unlock(&dbs_mutex);
return;
}
mutex_lock(&dbs_info->timer_mutex);
dbs_check_cpu(dbs_info);
queue_delayed_work_on(cpu, kconservative_wq, &dbs_info->work, delay);
mutex_unlock(&dbs_mutex);
mutex_unlock(&dbs_info->timer_mutex);
}
static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
@ -502,7 +497,6 @@ static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
delay -= jiffies % delay;
dbs_info->enable = 1;
INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);
queue_delayed_work_on(dbs_info->cpu, kconservative_wq, &dbs_info->work,
delay);
@ -510,7 +504,6 @@ static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
{
dbs_info->enable = 0;
cancel_delayed_work_sync(&dbs_info->work);
}
@ -529,9 +522,6 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
if ((!cpu_online(cpu)) || (!policy->cur))
return -EINVAL;
if (this_dbs_info->enable) /* Already enabled */
break;
mutex_lock(&dbs_mutex);
rc = sysfs_create_group(&policy->kobj, &dbs_attr_group);
@ -555,6 +545,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
this_dbs_info->down_skip = 0;
this_dbs_info->requested_freq = policy->cur;
mutex_init(&this_dbs_info->timer_mutex);
dbs_enable++;
/*
* Start the timerschedule work, when this governor
@ -596,6 +587,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
mutex_lock(&dbs_mutex);
sysfs_remove_group(&policy->kobj, &dbs_attr_group);
dbs_enable--;
mutex_destroy(&this_dbs_info->timer_mutex);
/*
* Stop the timerschedule work, when this governor
@ -611,7 +603,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
break;
case CPUFREQ_GOV_LIMITS:
mutex_lock(&dbs_mutex);
mutex_lock(&this_dbs_info->timer_mutex);
if (policy->max < this_dbs_info->cur_policy->cur)
__cpufreq_driver_target(
this_dbs_info->cur_policy,
@ -620,7 +612,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
__cpufreq_driver_target(
this_dbs_info->cur_policy,
policy->min, CPUFREQ_RELATION_L);
mutex_unlock(&dbs_mutex);
mutex_unlock(&this_dbs_info->timer_mutex);
break;
}