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-rw-r--r--drivers/cpufreq/cpufreq.c69
-rw-r--r--drivers/cpufreq/cpufreq_conservative.c49
-rw-r--r--drivers/cpufreq/cpufreq_ondemand.c77
3 files changed, 92 insertions, 103 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 6e2ec0b18948..c668ac855f71 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -761,6 +761,10 @@ static struct kobj_type ktype_cpufreq = {
* cpufreq_add_dev - add a CPU device
*
* Adds the cpufreq interface for a CPU device.
+ *
+ * The Oracle says: try running cpufreq registration/unregistration concurrently
+ * with with cpu hotplugging and all hell will break loose. Tried to clean this
+ * mess up, but more thorough testing is needed. - Mathieu
*/
static int cpufreq_add_dev(struct sys_device *sys_dev)
{
@@ -804,15 +808,12 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
goto nomem_out;
}
if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL)) {
- kfree(policy);
ret = -ENOMEM;
- goto nomem_out;
+ goto err_free_policy;
}
if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) {
- free_cpumask_var(policy->cpus);
- kfree(policy);
ret = -ENOMEM;
- goto nomem_out;
+ goto err_free_cpumask;
}
policy->cpu = cpu;
@@ -820,7 +821,8 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
/* Initially set CPU itself as the policy_cpu */
per_cpu(policy_cpu, cpu) = cpu;
- lock_policy_rwsem_write(cpu);
+ ret = (lock_policy_rwsem_write(cpu) < 0);
+ WARN_ON(ret);
init_completion(&policy->kobj_unregister);
INIT_WORK(&policy->update, handle_update);
@@ -833,7 +835,7 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
ret = cpufreq_driver->init(policy);
if (ret) {
dprintk("initialization failed\n");
- goto err_out;
+ goto err_unlock_policy;
}
policy->user_policy.min = policy->min;
policy->user_policy.max = policy->max;
@@ -858,15 +860,21 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
/* Check for existing affected CPUs.
* They may not be aware of it due to CPU Hotplug.
*/
- managed_policy = cpufreq_cpu_get(j); /* FIXME: Where is this released? What about error paths? */
+ managed_policy = cpufreq_cpu_get(j);
if (unlikely(managed_policy)) {
/* Set proper policy_cpu */
unlock_policy_rwsem_write(cpu);
per_cpu(policy_cpu, cpu) = managed_policy->cpu;
- if (lock_policy_rwsem_write(cpu) < 0)
- goto err_out_driver_exit;
+ if (lock_policy_rwsem_write(cpu) < 0) {
+ /* Should not go through policy unlock path */
+ if (cpufreq_driver->exit)
+ cpufreq_driver->exit(policy);
+ ret = -EBUSY;
+ cpufreq_cpu_put(managed_policy);
+ goto err_free_cpumask;
+ }
spin_lock_irqsave(&cpufreq_driver_lock, flags);
cpumask_copy(managed_policy->cpus, policy->cpus);
@@ -877,12 +885,14 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
ret = sysfs_create_link(&sys_dev->kobj,
&managed_policy->kobj,
"cpufreq");
- if (ret)
- goto err_out_driver_exit;
-
- cpufreq_debug_enable_ratelimit();
- ret = 0;
- goto err_out_driver_exit; /* call driver->exit() */
+ if (!ret)
+ cpufreq_cpu_put(managed_policy);
+ /*
+ * Success. We only needed to be added to the mask.
+ * Call driver->exit() because only the cpu parent of
+ * the kobj needed to call init().
+ */
+ goto out_driver_exit; /* call driver->exit() */
}
}
#endif
@@ -892,25 +902,25 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq, &sys_dev->kobj,
"cpufreq");
if (ret)
- goto err_out_driver_exit;
+ goto out_driver_exit;
/* set up files for this cpu device */
drv_attr = cpufreq_driver->attr;
while ((drv_attr) && (*drv_attr)) {
ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
if (ret)
- goto err_out_driver_exit;
+ goto err_out_kobj_put;
drv_attr++;
}
if (cpufreq_driver->get) {
ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
if (ret)
- goto err_out_driver_exit;
+ goto err_out_kobj_put;
}
if (cpufreq_driver->target) {
ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
if (ret)
- goto err_out_driver_exit;
+ goto err_out_kobj_put;
}
spin_lock_irqsave(&cpufreq_driver_lock, flags);
@@ -928,12 +938,14 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
continue;
dprintk("CPU %u already managed, adding link\n", j);
- cpufreq_cpu_get(cpu);
+ managed_policy = cpufreq_cpu_get(cpu);
cpu_sys_dev = get_cpu_sysdev(j);
ret = sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj,
"cpufreq");
- if (ret)
+ if (ret) {
+ cpufreq_cpu_put(managed_policy);
goto err_out_unregister;
+ }
}
policy->governor = NULL; /* to assure that the starting sequence is
@@ -965,17 +977,20 @@ err_out_unregister:
per_cpu(cpufreq_cpu_data, j) = NULL;
spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
+err_out_kobj_put:
kobject_put(&policy->kobj);
wait_for_completion(&policy->kobj_unregister);
-err_out_driver_exit:
+out_driver_exit:
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);
-err_out:
+err_unlock_policy:
unlock_policy_rwsem_write(cpu);
+err_free_cpumask:
+ free_cpumask_var(policy->cpus);
+err_free_policy:
kfree(policy);
-
nomem_out:
module_put(cpufreq_driver->owner);
module_out:
@@ -1070,8 +1085,6 @@ static int __cpufreq_remove_dev(struct sys_device *sys_dev)
spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
#endif
- unlock_policy_rwsem_write(cpu);
-
if (cpufreq_driver->target)
__cpufreq_governor(data, CPUFREQ_GOV_STOP);
@@ -1088,6 +1101,8 @@ static int __cpufreq_remove_dev(struct sys_device *sys_dev)
if (cpufreq_driver->exit)
cpufreq_driver->exit(data);
+ unlock_policy_rwsem_write(cpu);
+
free_cpumask_var(data->related_cpus);
free_cpumask_var(data->cpus);
kfree(data);
diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c
index 7fc58af748b4..57490502b21c 100644
--- a/drivers/cpufreq/cpufreq_conservative.c
+++ b/drivers/cpufreq/cpufreq_conservative.c
@@ -63,22 +63,20 @@ 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);
static unsigned int dbs_enable; /* number of CPUs using this policy */
/*
- * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug
- * lock and dbs_mutex. cpu_hotplug lock should always be held before
- * dbs_mutex. If any function that can potentially take cpu_hotplug lock
- * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then
- * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock
- * is recursive for the same process. -Venki
- * DEADLOCK ALERT! (2) : do_dbs_timer() must not take the dbs_mutex, because it
- * would deadlock with cancel_delayed_work_sync(), which is needed for proper
- * raceless workqueue teardown.
+ * dbs_mutex protects data in dbs_tuners_ins from concurrent changes on
+ * different CPUs. It protects dbs_enable in governor start/stop.
*/
static DEFINE_MUTEX(dbs_mutex);
@@ -143,9 +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;
/*
@@ -488,18 +483,12 @@ static void do_dbs_timer(struct work_struct *work)
delay -= jiffies % delay;
- if (lock_policy_rwsem_write(cpu) < 0)
- return;
-
- if (!dbs_info->enable) {
- unlock_policy_rwsem_write(cpu);
- return;
- }
+ mutex_lock(&dbs_info->timer_mutex);
dbs_check_cpu(dbs_info);
queue_delayed_work_on(cpu, kconservative_wq, &dbs_info->work, delay);
- unlock_policy_rwsem_write(cpu);
+ mutex_unlock(&dbs_info->timer_mutex);
}
static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
@@ -508,7 +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);
@@ -516,7 +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);
}
@@ -535,9 +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);
@@ -561,6 +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
@@ -590,17 +575,19 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
&dbs_cpufreq_notifier_block,
CPUFREQ_TRANSITION_NOTIFIER);
}
- dbs_timer_init(this_dbs_info);
-
mutex_unlock(&dbs_mutex);
+ dbs_timer_init(this_dbs_info);
+
break;
case CPUFREQ_GOV_STOP:
- mutex_lock(&dbs_mutex);
dbs_timer_exit(this_dbs_info);
+
+ 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
@@ -616,7 +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,
@@ -625,7 +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;
}
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 1911d1729353..d6ba14276bb1 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -70,23 +70,21 @@ struct cpu_dbs_info_s {
unsigned int freq_lo_jiffies;
unsigned int freq_hi_jiffies;
int cpu;
- unsigned int enable:1,
- sample_type:1;
+ unsigned int sample_type: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);
static unsigned int dbs_enable; /* number of CPUs using this policy */
/*
- * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug
- * lock and dbs_mutex. cpu_hotplug lock should always be held before
- * dbs_mutex. If any function that can potentially take cpu_hotplug lock
- * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then
- * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock
- * is recursive for the same process. -Venki
- * DEADLOCK ALERT! (2) : do_dbs_timer() must not take the dbs_mutex, because it
- * would deadlock with cancel_delayed_work_sync(), which is needed for proper
- * raceless workqueue teardown.
+ * dbs_mutex protects data in dbs_tuners_ins from concurrent changes on
+ * different CPUs. It protects dbs_enable in governor start/stop.
*/
static DEFINE_MUTEX(dbs_mutex);
@@ -192,13 +190,18 @@ static unsigned int powersave_bias_target(struct cpufreq_policy *policy,
return freq_hi;
}
+static void ondemand_powersave_bias_init_cpu(int cpu)
+{
+ struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
+ dbs_info->freq_table = cpufreq_frequency_get_table(cpu);
+ dbs_info->freq_lo = 0;
+}
+
static void ondemand_powersave_bias_init(void)
{
int i;
for_each_online_cpu(i) {
- struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, i);
- dbs_info->freq_table = cpufreq_frequency_get_table(i);
- dbs_info->freq_lo = 0;
+ ondemand_powersave_bias_init_cpu(i);
}
}
@@ -240,12 +243,10 @@ static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
unsigned int input;
int ret;
ret = sscanf(buf, "%u", &input);
+ if (ret != 1)
+ return -EINVAL;
mutex_lock(&dbs_mutex);
- if (ret != 1) {
- mutex_unlock(&dbs_mutex);
- return -EINVAL;
- }
dbs_tuners_ins.sampling_rate = max(input, min_sampling_rate);
mutex_unlock(&dbs_mutex);
@@ -259,13 +260,12 @@ static ssize_t store_up_threshold(struct cpufreq_policy *unused,
int ret;
ret = sscanf(buf, "%u", &input);
- mutex_lock(&dbs_mutex);
if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
input < MIN_FREQUENCY_UP_THRESHOLD) {
- mutex_unlock(&dbs_mutex);
return -EINVAL;
}
+ mutex_lock(&dbs_mutex);
dbs_tuners_ins.up_threshold = input;
mutex_unlock(&dbs_mutex);
@@ -363,9 +363,6 @@ static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
struct cpufreq_policy *policy;
unsigned int j;
- if (!this_dbs_info->enable)
- return;
-
this_dbs_info->freq_lo = 0;
policy = this_dbs_info->cur_policy;
@@ -493,14 +490,7 @@ static void do_dbs_timer(struct work_struct *work)
int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
delay -= jiffies % delay;
-
- if (lock_policy_rwsem_write(cpu) < 0)
- return;
-
- if (!dbs_info->enable) {
- unlock_policy_rwsem_write(cpu);
- return;
- }
+ mutex_lock(&dbs_info->timer_mutex);
/* Common NORMAL_SAMPLE setup */
dbs_info->sample_type = DBS_NORMAL_SAMPLE;
@@ -517,7 +507,7 @@ static void do_dbs_timer(struct work_struct *work)
dbs_info->freq_lo, CPUFREQ_RELATION_H);
}
queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
- unlock_policy_rwsem_write(cpu);
+ mutex_unlock(&dbs_info->timer_mutex);
}
static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
@@ -526,8 +516,6 @@ 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;
- ondemand_powersave_bias_init();
dbs_info->sample_type = DBS_NORMAL_SAMPLE;
INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);
queue_delayed_work_on(dbs_info->cpu, kondemand_wq, &dbs_info->work,
@@ -536,7 +524,6 @@ 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);
}
@@ -555,19 +542,15 @@ 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);
- dbs_enable++;
rc = sysfs_create_group(&policy->kobj, &dbs_attr_group);
if (rc) {
- dbs_enable--;
mutex_unlock(&dbs_mutex);
return rc;
}
+ dbs_enable++;
for_each_cpu(j, policy->cpus) {
struct cpu_dbs_info_s *j_dbs_info;
j_dbs_info = &per_cpu(cpu_dbs_info, j);
@@ -581,6 +564,8 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
}
}
this_dbs_info->cpu = cpu;
+ ondemand_powersave_bias_init_cpu(cpu);
+ mutex_init(&this_dbs_info->timer_mutex);
/*
* Start the timerschedule work, when this governor
* is used for first time
@@ -598,29 +583,31 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
max(min_sampling_rate,
latency * LATENCY_MULTIPLIER);
}
- dbs_timer_init(this_dbs_info);
-
mutex_unlock(&dbs_mutex);
+
+ dbs_timer_init(this_dbs_info);
break;
case CPUFREQ_GOV_STOP:
- mutex_lock(&dbs_mutex);
dbs_timer_exit(this_dbs_info);
+
+ mutex_lock(&dbs_mutex);
sysfs_remove_group(&policy->kobj, &dbs_attr_group);
+ mutex_destroy(&this_dbs_info->timer_mutex);
dbs_enable--;
mutex_unlock(&dbs_mutex);
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,
policy->max, CPUFREQ_RELATION_H);
else if (policy->min > this_dbs_info->cur_policy->cur)
__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;
}
return 0;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-23 15:40:43 +0100