Merge branch 'percpu-for-linus' into percpu-for-next
Conflicts:
arch/sparc/kernel/smp_64.c
arch/x86/kernel/cpu/perf_counter.c
arch/x86/kernel/setup_percpu.c
drivers/cpufreq/cpufreq_ondemand.c
mm/percpu.c
Conflicts in core and arch percpu codes are mostly from commit
ed78e1e078dd44249f88b1dd8c76dafb39567161 which substituted many
num_possible_cpus() with nr_cpu_ids. As for-next branch has moved all
the first chunk allocators into mm/percpu.c, the changes are moved
from arch code to mm/percpu.c.
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 36f292a..d7a528c 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -70,23 +70,21 @@
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, od_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);
@@ -193,13 +191,18 @@
return freq_hi;
}
+static void ondemand_powersave_bias_init_cpu(int cpu)
+{
+ struct cpu_dbs_info_s *dbs_info = &per_cpu(od_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(od_cpu_dbs_info, i);
- dbs_info->freq_table = cpufreq_frequency_get_table(i);
- dbs_info->freq_lo = 0;
+ ondemand_powersave_bias_init_cpu(i);
}
}
@@ -241,12 +244,10 @@
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);
@@ -260,13 +261,12 @@
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);
@@ -364,9 +364,6 @@
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;
@@ -494,14 +491,7 @@
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;
@@ -518,7 +508,7 @@
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)
@@ -527,8 +517,6 @@
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,
@@ -537,7 +525,6 @@
static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
{
- dbs_info->enable = 0;
cancel_delayed_work_sync(&dbs_info->work);
}
@@ -556,19 +543,15 @@
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(od_cpu_dbs_info, j);
@@ -582,6 +565,8 @@
}
}
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
@@ -599,29 +584,31 @@
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;