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author | Herbert Xu <herbert@gondor.apana.org.au> | 2012-05-15 09:21:26 +0200 |
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committer | Herbert Xu <herbert@gondor.apana.org.au> | 2012-05-15 09:21:26 +0200 |
commit | b29e2679d0da91c60d3ac190d9c3bd65ac2f68c5 (patch) | |
tree | 518ec8f4bfd316e91bcc30f434edb78529557eba /drivers/cpufreq/cpufreq_ondemand.c | |
parent | crypto: ux500 - Add driver for HASH hardware (diff) | |
parent | Merge tag 'soc2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc (diff) | |
download | linux-b29e2679d0da91c60d3ac190d9c3bd65ac2f68c5.tar.xz linux-b29e2679d0da91c60d3ac190d9c3bd65ac2f68c5.zip |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux
Merge mainline to add prerequisite for ARM ux500 crypto support.
Diffstat (limited to 'drivers/cpufreq/cpufreq_ondemand.c')
-rw-r--r-- | drivers/cpufreq/cpufreq_ondemand.c | 58 |
1 files changed, 57 insertions, 1 deletions
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index c3e0652520a1..836e9b062e5e 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -257,6 +257,62 @@ show_one(sampling_down_factor, sampling_down_factor); show_one(ignore_nice_load, ignore_nice); show_one(powersave_bias, powersave_bias); +/** + * update_sampling_rate - update sampling rate effective immediately if needed. + * @new_rate: new sampling rate + * + * If new rate is smaller than the old, simply updaing + * dbs_tuners_int.sampling_rate might not be appropriate. For example, + * if the original sampling_rate was 1 second and the requested new sampling + * rate is 10 ms because the user needs immediate reaction from ondemand + * governor, but not sure if higher frequency will be required or not, + * then, the governor may change the sampling rate too late; up to 1 second + * later. Thus, if we are reducing the sampling rate, we need to make the + * new value effective immediately. + */ +static void update_sampling_rate(unsigned int new_rate) +{ + int cpu; + + dbs_tuners_ins.sampling_rate = new_rate + = max(new_rate, min_sampling_rate); + + for_each_online_cpu(cpu) { + struct cpufreq_policy *policy; + struct cpu_dbs_info_s *dbs_info; + unsigned long next_sampling, appointed_at; + + policy = cpufreq_cpu_get(cpu); + if (!policy) + continue; + dbs_info = &per_cpu(od_cpu_dbs_info, policy->cpu); + cpufreq_cpu_put(policy); + + mutex_lock(&dbs_info->timer_mutex); + + if (!delayed_work_pending(&dbs_info->work)) { + mutex_unlock(&dbs_info->timer_mutex); + continue; + } + + next_sampling = jiffies + usecs_to_jiffies(new_rate); + appointed_at = dbs_info->work.timer.expires; + + + if (time_before(next_sampling, appointed_at)) { + + mutex_unlock(&dbs_info->timer_mutex); + cancel_delayed_work_sync(&dbs_info->work); + mutex_lock(&dbs_info->timer_mutex); + + schedule_delayed_work_on(dbs_info->cpu, &dbs_info->work, + usecs_to_jiffies(new_rate)); + + } + mutex_unlock(&dbs_info->timer_mutex); + } +} + static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b, const char *buf, size_t count) { @@ -265,7 +321,7 @@ static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b, ret = sscanf(buf, "%u", &input); if (ret != 1) return -EINVAL; - dbs_tuners_ins.sampling_rate = max(input, min_sampling_rate); + update_sampling_rate(input); return count; } |