Messages in this thread | | | Date | Thu, 17 May 2018 10:36:11 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH RFC] schedutil: Allow cpufreq requests to be made even when kthread kicked |
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On 16-05-18, 15:45, Joel Fernandes (Google) wrote: > kernel/sched/cpufreq_schedutil.c | 36 +++++++++++++++++++++++++------- > 1 file changed, 28 insertions(+), 8 deletions(-) > > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c > index e13df951aca7..a87fc281893d 100644 > --- a/kernel/sched/cpufreq_schedutil.c > +++ b/kernel/sched/cpufreq_schedutil.c > @@ -92,9 +92,6 @@ static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time) > !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)) { > sg_policy->need_freq_update = false; > /* > @@ -129,8 +126,11 @@ static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time, > policy->cur = next_freq; > trace_cpu_frequency(next_freq, smp_processor_id()); > } else { > - sg_policy->work_in_progress = true; > - irq_work_queue(&sg_policy->irq_work); > + /* Don't queue request if one was already queued */ > + if (!sg_policy->work_in_progress) {
Merge it above to make it "else if".
> + sg_policy->work_in_progress = true; > + irq_work_queue(&sg_policy->irq_work); > + } > } > } > > @@ -291,6 +291,15 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, > > ignore_dl_rate_limit(sg_cpu, sg_policy); > > + /* > + * For slow-switch systems, single policy requests can't run at the > + * moment if the governor thread is already processing a pending > + * frequency switch request, this can be fixed by acquiring update_lock > + * while updating next_freq and work_in_progress but we prefer not to. > + */ > + if (sg_policy->work_in_progress) > + return; > +
@Rafael: Do you think its worth start using the lock now for unshared policies ?
> if (!sugov_should_update_freq(sg_policy, time)) > return; > > @@ -382,13 +391,24 @@ sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags) > static void sugov_work(struct kthread_work *work) > { > struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work); > + unsigned int freq; > + unsigned long flags; > + > + /* > + * Hold sg_policy->update_lock shortly to handle the case where: > + * incase sg_policy->next_freq is read here, and then updated by > + * sugov_update_shared just before work_in_progress is set to false > + * here, we may miss queueing the new update. > + */ > + raw_spin_lock_irqsave(&sg_policy->update_lock, flags); > + freq = sg_policy->next_freq; > + sg_policy->work_in_progress = false; > + raw_spin_unlock_irqrestore(&sg_policy->update_lock, flags); > > mutex_lock(&sg_policy->work_lock); > - __cpufreq_driver_target(sg_policy->policy, sg_policy->next_freq, > + __cpufreq_driver_target(sg_policy->policy, freq, > CPUFREQ_RELATION_L);
No need of line break anymore.
> mutex_unlock(&sg_policy->work_lock); > - > - sg_policy->work_in_progress = false; > } > > static void sugov_irq_work(struct irq_work *irq_work)
LGTM.
-- viresh
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