On Monday, November 26, 2012 05:39:52 PM Fabio Baltieri wrote:
> From: Rickard Andersson <rickard.andersson@xxxxxxxxxxxxxx>
>
> This patch fixes a bug that occurred when we had load on a secondary CPU
> and the primary CPU was sleeping. Only one sampling timer was spawned
> and it was spawned as a deferred timer on the primary CPU, so when a
> secondary CPU had a change in load this was not detected by the cpufreq
> governor (both ondemand and conservative).
>
> This patch make sure that deferred timers are run on all CPUs in the
> case of software controlled CPUs that run on the same frequency.
>
> Signed-off-by: Rickard Andersson <rickard.andersson@xxxxxxxxxxxxxx>
> Signed-off-by: Fabio Baltieri <fabio.baltieri@xxxxxxxxxx>
> ---
> drivers/cpufreq/cpufreq_conservative.c | 3 +-
> drivers/cpufreq/cpufreq_governor.c | 52 ++++++++++++++++++++++++++++++----
> drivers/cpufreq/cpufreq_governor.h | 1 +
> drivers/cpufreq/cpufreq_ondemand.c | 3 +-
> 4 files changed, 51 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c
> index 64ef737..b9d7f14 100644
> --- a/drivers/cpufreq/cpufreq_conservative.c
> +++ b/drivers/cpufreq/cpufreq_conservative.c
> @@ -122,7 +122,8 @@ static void cs_dbs_timer(struct work_struct *work)
>
> dbs_check_cpu(&cs_dbs_data, cpu);
>
> - schedule_delayed_work_on(cpu, &dbs_info->cdbs.work, delay);
> + schedule_delayed_work_on(smp_processor_id(), &dbs_info->cdbs.work,
> + delay);
> mutex_unlock(&dbs_info->cdbs.timer_mutex);
> }
>
> diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
> index 6c5f1d3..a00f02d 100644
> --- a/drivers/cpufreq/cpufreq_governor.c
> +++ b/drivers/cpufreq/cpufreq_governor.c
> @@ -161,13 +161,31 @@ void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
> }
> EXPORT_SYMBOL_GPL(dbs_check_cpu);
>
> +bool dbs_sw_coordinated_cpus(struct cpu_dbs_common_info *cdbs)
> +{
> + struct cpufreq_policy *policy = cdbs->cur_policy;
> +
> + return cpumask_weight(policy->cpus) > 1;
> +}
> +EXPORT_SYMBOL_GPL(dbs_sw_coordinated_cpus);
> +
> static inline void dbs_timer_init(struct dbs_data *dbs_data,
> - struct cpu_dbs_common_info *cdbs, unsigned int sampling_rate)
> + struct cpu_dbs_common_info *cdbs,
> + unsigned int sampling_rate,
> + int cpu)
> {
> int delay = delay_for_sampling_rate(sampling_rate);
> + struct cpu_dbs_common_info *cdbs_local = dbs_data->get_cpu_cdbs(cpu);
> + struct od_cpu_dbs_info_s *od_dbs_info;
> +
> + cancel_delayed_work_sync(&cdbs_local->work);
> +
> + if (dbs_data->governor == GOV_ONDEMAND) {
> + od_dbs_info = dbs_data->get_cpu_dbs_info_s(cpu);
> + od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
> + }
The patch looks good in general except for the special case above.
Why exactly is it necessary?
Rafael
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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