Currently, whenever governor->governor() is called for CPUFRREQ_GOV_START event we reset few tunables of governor. Which isn't correct, as this routine is called for every cpu hot-[un]plugging event. We should actually be resetting these only when the governor module is removed and re-installed.

Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- drivers/cpufreq/cpufreq.c | 4 ++++ drivers/cpufreq/cpufreq_governor.c | 24 ++++++++++++++++-------- include/linux/cpufreq.h | 1 + 3 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 8d521422..9656420 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1561,6 +1561,9 @@ static int __cpufreq_governor(struct cpufreq_policy *policy, policy->cpu, event); ret = policy->governor->governor(policy, event);

+ if (!policy->governor->initialized && (event == CPUFREQ_GOV_START)) + policy->governor->initialized = 1; + /* we keep one module reference alive for each CPU governed by this CPU */ if ((event != CPUFREQ_GOV_START) || ret) @@ -1584,6 +1587,7 @@ int cpufreq_register_governor(struct cpufreq_governor *governor)

mutex_lock(&cpufreq_governor_mutex);

+ governor->initialized = 0; err = -EBUSY; if (__find_governor(governor->name) == NULL) { err = 0; diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index 7aaa9b1..79795c4 100644 --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -254,11 +254,6 @@ int cpufreq_governor_dbs(struct dbs_data *dbs_data, return rc; }

- /* policy latency is in nS. Convert it to uS first */ - latency = policy->cpuinfo.transition_latency / 1000; - if (latency == 0) - latency = 1; - /* * conservative does not implement micro like ondemand * governor, thus we are bound to jiffes/HZ @@ -270,20 +265,33 @@ int cpufreq_governor_dbs(struct dbs_data *dbs_data, cpufreq_register_notifier(cs_ops->notifier_block, CPUFREQ_TRANSITION_NOTIFIER);

- dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO * - jiffies_to_usecs(10); + if (!policy->governor->initialized) + dbs_data->min_sampling_rate = + MIN_SAMPLING_RATE_RATIO * + jiffies_to_usecs(10); } else { od_dbs_info->rate_mult = 1; od_dbs_info->sample_type = OD_NORMAL_SAMPLE; od_ops->powersave_bias_init_cpu(cpu); - od_tuners->io_is_busy = od_ops->io_busy(); + + if (!policy->governor->initialized) + od_tuners->io_is_busy = od_ops->io_busy(); }

+ if (policy->governor->initialized) + goto unlock; + + /* policy latency is in nS. Convert it to uS first */ + latency = policy->cpuinfo.transition_latency / 1000; + if (latency == 0) + latency = 1; + /* Bring kernel and HW constraints together */ dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate, MIN_LATENCY_MULTIPLIER * latency); *sampling_rate = max(dbs_data->min_sampling_rate, latency * LATENCY_MULTIPLIER); +unlock: mutex_unlock(&dbs_data->mutex);

/* Initiate timer time stamp */ diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index feb360c..6bf3f2d 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -183,6 +183,7 @@ static inline unsigned long cpufreq_scale(unsigned long old, u_int div, u_int mu

struct cpufreq_governor { char name[CPUFREQ_NAME_LEN]; + int initialized; int (*governor) (struct cpufreq_policy *policy, unsigned int event); ssize_t (*show_setspeed) (struct cpufreq_policy *policy,