On 22-05-18, 13:31, Rafael J. Wysocki wrote:
> So below is my (compiled-only) version of the $subject patch, obviously based
> on the Joel's work.
>
> Roughly, what it does is to move the fast_switch_enabled path entirely to
> sugov_update_single() and take the spinlock around sugov_update_commit()
> in the one-CPU case too.
>
> ---
> kernel/sched/cpufreq_schedutil.c | 57
> ++++++++++++++++++++++++++-------------
> 1 file changed, 38 insertions(+), 19 deletions(-)
>
> Index: linux-pm/kernel/sched/cpufreq_schedutil.c
> ===================================================================
> --- linux-pm.orig/kernel/sched/cpufreq_schedutil.c
> +++ linux-pm/kernel/sched/cpufreq_schedutil.c
> @@ -92,9 +92,6 @@ static bool sugov_should_update_freq(str
> !cpufreq_can_do_remote_dvfs(sg_policy->policy))
> return false;
>
> - if (sg_policy->work_in_progress)
> - return false;
> -
> if (unlikely(sg_policy->need_freq_update))
> return true;
>
> @@ -103,25 +100,25 @@ static bool sugov_should_update_freq(str
> return delta_ns >= sg_policy->freq_update_delay_ns;
> }
>
> -static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time,
> - unsigned int next_freq)
> +static bool sugov_update_next_freq(struct sugov_policy *sg_policy, u64 time,
> + unsigned int next_freq)
> {
> - struct cpufreq_policy *policy = sg_policy->policy;
> -
> if (sg_policy->next_freq == next_freq)
> - return;
> + return false;
>
> sg_policy->next_freq = next_freq;
> sg_policy->last_freq_update_time = time;
>
> - if (policy->fast_switch_enabled) {
> - next_freq = cpufreq_driver_fast_switch(policy, next_freq);
> - if (!next_freq)
> - return;
> + return true;
> +}
>
> - policy->cur = next_freq;
> - trace_cpu_frequency(next_freq, smp_processor_id());
> - } else {
> +static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time,
> + unsigned int next_freq)
> +{
> + if (!sugov_update_next_freq(sg_policy, time, next_freq))
> + return;
> +
> + if (!sg_policy->work_in_progress) {
> sg_policy->work_in_progress = true;
> irq_work_queue(&sg_policy->irq_work);
> }
> @@ -277,6 +274,7 @@ static void sugov_update_single(struct u
> {
> struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu,
> update_util);
> struct sugov_policy *sg_policy = sg_cpu->sg_policy;
> + struct cpufreq_policy *policy = sg_policy->policy;
> unsigned long util, max;
> unsigned int next_f;
> bool busy;
> @@ -307,7 +305,23 @@ static void sugov_update_single(struct u
> sg_policy->cached_raw_freq = 0;
> }
>
> - sugov_update_commit(sg_policy, time, next_f);
> + if (policy->fast_switch_enabled) {
Why do you assume that fast switch isn't possible in shared policy
cases ? It infact is already enabled for few drivers.
--
viresh
