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Re: [PATCH v6 2/8] arm: parse cpu capacity-dmips-mhz from DT

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  Re: [PATCH v6 2/8] arm: parse cpu capacity-dmips-mhz from DT Juri Lelli <juri.lelli@arm.com> - 2016-08-30 18:30 +0200
    Re: [PATCH v6 2/8] arm: parse cpu capacity-dmips-mhz from DT Vincent Guittot <vincent.guittot@linaro.org> - 2016-08-31 10:20 +0200
      Re: [PATCH v6 2/8] arm: parse cpu capacity-dmips-mhz from DT Juri Lelli <juri.lelli@arm.com> - 2016-08-31 19:10 +0200
        Re: [PATCH v6 2/8] arm: parse cpu capacity-dmips-mhz from DT Vincent Guittot <vincent.guittot@linaro.org> - 2016-09-01 10:30 +0200
          Re: [PATCH v6 2/8] arm: parse cpu capacity-dmips-mhz from DT Juri Lelli <juri.lelli@arm.com> - 2016-09-01 11:00 +0200

#1472615 — Re: [PATCH v6 2/8] arm: parse cpu capacity-dmips-mhz from DT

Hi Vincent,

On 16/08/16 10:20, Vincent Guittot wrote:
> Hi Juri,
> 
> 
> On 19 July 2016 at 14:40, Juri Lelli <juri.lelli@arm.com> wrote:

[...]

> > +static int
> > +init_cpu_capacity_callback(struct notifier_block *nb,
> > +                          unsigned long val,
> > +                          void *data)
> > +{
> > +       struct cpufreq_policy *policy = data;
> > +       int cpu;
> > +
> > +       if (cap_parsing_failed || cap_parsing_done)
> > +               return 0;
> > +
> > +       switch (val) {
> > +       case CPUFREQ_NOTIFY:
> > +               pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
> > +                               cpumask_pr_args(policy->related_cpus),
> > +                               cpumask_pr_args(cpus_to_visit));
> > +               cpumask_andnot(cpus_to_visit,
> > +                              cpus_to_visit,
> > +                              policy->related_cpus);
> > +               for_each_cpu(cpu, policy->related_cpus) {
> > +                       raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) *
> > +                                           policy->max / 1000UL;
> 
> Should it be policy->cpuinfo.max_freq instead of policy->max ?
> 

Right. I'll fix the arm64 bits as well.

> > +                       capacity_scale = max(raw_capacity[cpu], capacity_scale);
> > +               }
> > +               if (cpumask_empty(cpus_to_visit)) {
> > +                       normalize_cpu_capacity();
> > +                       kfree(raw_capacity);
> > +                       pr_debug("cpu_capacity: parsing done\n");
> > +                       cap_parsing_done = true;
> 
> ok so you do that once with the 1st governor that will be registered
> for the CPU. Can't you unregister the notifier then ?
> 

I tried, but the only place I could find to unregister it is from the
callback itself; and it is not possible to do so AFAIK. Suggestions?

Thanks for the review.

Best,

- Juri

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#1473166

On 30 August 2016 at 18:28, Juri Lelli <juri.lelli@arm.com> wrote:
> Hi Vincent,
>
> On 16/08/16 10:20, Vincent Guittot wrote:
>> Hi Juri,
>>
>>
>> On 19 July 2016 at 14:40, Juri Lelli <juri.lelli@arm.com> wrote:
>
> [...]
>
>> > +static int
>> > +init_cpu_capacity_callback(struct notifier_block *nb,
>> > +                          unsigned long val,
>> > +                          void *data)
>> > +{
>> > +       struct cpufreq_policy *policy = data;
>> > +       int cpu;
>> > +
>> > +       if (cap_parsing_failed || cap_parsing_done)
>> > +               return 0;
>> > +
>> > +       switch (val) {
>> > +       case CPUFREQ_NOTIFY:
>> > +               pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
>> > +                               cpumask_pr_args(policy->related_cpus),
>> > +                               cpumask_pr_args(cpus_to_visit));
>> > +               cpumask_andnot(cpus_to_visit,
>> > +                              cpus_to_visit,
>> > +                              policy->related_cpus);
>> > +               for_each_cpu(cpu, policy->related_cpus) {
>> > +                       raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) *
>> > +                                           policy->max / 1000UL;
>>
>> Should it be policy->cpuinfo.max_freq instead of policy->max ?
>>
>
> Right. I'll fix the arm64 bits as well.
>
>> > +                       capacity_scale = max(raw_capacity[cpu], capacity_scale);
>> > +               }
>> > +               if (cpumask_empty(cpus_to_visit)) {
>> > +                       normalize_cpu_capacity();
>> > +                       kfree(raw_capacity);
>> > +                       pr_debug("cpu_capacity: parsing done\n");
>> > +                       cap_parsing_done = true;
>>
>> ok so you do that once with the 1st governor that will be registered
>> for the CPU. Can't you unregister the notifier then ?
>>
>
> I tried, but the only place I could find to unregister it is from the
> callback itself; and it is not possible to do so AFAIK. Suggestions?

yes, you're right
Can't you queue a work to unregister your callback ?
That's may be overkill but it seems weird to keep this notifier that
will do nothing, registered for the whole life of the system

>
> Thanks for the review.
>
> Best,
>
> - Juri

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#1473727

On 31/08/16 10:14, Vincent Guittot wrote:
> On 30 August 2016 at 18:28, Juri Lelli <juri.lelli@arm.com> wrote:
> > Hi Vincent,
> >
> > On 16/08/16 10:20, Vincent Guittot wrote:
> >> Hi Juri,
> >>
> >>
> >> On 19 July 2016 at 14:40, Juri Lelli <juri.lelli@arm.com> wrote:
> >
> > [...]
> >
> >> > +static int
> >> > +init_cpu_capacity_callback(struct notifier_block *nb,
> >> > +                          unsigned long val,
> >> > +                          void *data)
> >> > +{
> >> > +       struct cpufreq_policy *policy = data;
> >> > +       int cpu;
> >> > +
> >> > +       if (cap_parsing_failed || cap_parsing_done)
> >> > +               return 0;
> >> > +
> >> > +       switch (val) {
> >> > +       case CPUFREQ_NOTIFY:
> >> > +               pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
> >> > +                               cpumask_pr_args(policy->related_cpus),
> >> > +                               cpumask_pr_args(cpus_to_visit));
> >> > +               cpumask_andnot(cpus_to_visit,
> >> > +                              cpus_to_visit,
> >> > +                              policy->related_cpus);
> >> > +               for_each_cpu(cpu, policy->related_cpus) {
> >> > +                       raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) *
> >> > +                                           policy->max / 1000UL;
> >>
> >> Should it be policy->cpuinfo.max_freq instead of policy->max ?
> >>
> >
> > Right. I'll fix the arm64 bits as well.
> >
> >> > +                       capacity_scale = max(raw_capacity[cpu], capacity_scale);
> >> > +               }
> >> > +               if (cpumask_empty(cpus_to_visit)) {
> >> > +                       normalize_cpu_capacity();
> >> > +                       kfree(raw_capacity);
> >> > +                       pr_debug("cpu_capacity: parsing done\n");
> >> > +                       cap_parsing_done = true;
> >>
> >> ok so you do that once with the 1st governor that will be registered
> >> for the CPU. Can't you unregister the notifier then ?
> >>
> >
> > I tried, but the only place I could find to unregister it is from the
> > callback itself; and it is not possible to do so AFAIK. Suggestions?
> 
> yes, you're right
> Can't you queue a work to unregister your callback ?

You mean something like this? I guess I thought it would be much more
ugly. :)

If it looks OK, I'll add the same for arm64 and test it a bit more.

--->8---
 arch/arm/kernel/topology.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
index cbc57c287145..672ae22e2768 100644
--- a/arch/arm/kernel/topology.c
+++ b/arch/arm/kernel/topology.c
@@ -215,7 +215,8 @@ static void normalize_cpu_capacity(void)
 
 #ifdef CONFIG_CPU_FREQ
 static cpumask_var_t cpus_to_visit;
-static bool cap_parsing_done;
+static void parsing_done_workfn(struct work_struct *work);
+static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
 
 static int
 init_cpu_capacity_callback(struct notifier_block *nb,
@@ -225,7 +226,7 @@ init_cpu_capacity_callback(struct notifier_block *nb,
 	struct cpufreq_policy *policy = data;
 	int cpu;
 
-	if (cap_parsing_failed || cap_parsing_done)
+	if (cap_parsing_failed)
 		return 0;
 
 	switch (val) {
@@ -245,7 +246,7 @@ init_cpu_capacity_callback(struct notifier_block *nb,
 			normalize_cpu_capacity();
 			kfree(raw_capacity);
 			pr_debug("cpu_capacity: parsing done\n");
-			cap_parsing_done = true;
+			schedule_work(&parsing_done_work);
 		}
 	}
 	return 0;
@@ -270,6 +271,13 @@ static int __init register_cpufreq_notifier(void)
 					 CPUFREQ_POLICY_NOTIFIER);
 }
 core_initcall(register_cpufreq_notifier);
+
+static void parsing_done_workfn(struct work_struct *work)
+{
+	cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
+					 CPUFREQ_POLICY_NOTIFIER);
+}
+
 #else
 static int __init free_raw_capacity(void)
 {

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#1474164

On 31 August 2016 at 19:08, Juri Lelli <juri.lelli@arm.com> wrote:
> On 31/08/16 10:14, Vincent Guittot wrote:
>> On 30 August 2016 at 18:28, Juri Lelli <juri.lelli@arm.com> wrote:
>> > Hi Vincent,
>> >
>> > On 16/08/16 10:20, Vincent Guittot wrote:
>> >> Hi Juri,
>> >>
>> >>
>> >> On 19 July 2016 at 14:40, Juri Lelli <juri.lelli@arm.com> wrote:
>> >
>> > [...]
>> >
>> >> > +static int
>> >> > +init_cpu_capacity_callback(struct notifier_block *nb,
>> >> > +                          unsigned long val,
>> >> > +                          void *data)
>> >> > +{
>> >> > +       struct cpufreq_policy *policy = data;
>> >> > +       int cpu;
>> >> > +
>> >> > +       if (cap_parsing_failed || cap_parsing_done)
>> >> > +               return 0;
>> >> > +
>> >> > +       switch (val) {
>> >> > +       case CPUFREQ_NOTIFY:
>> >> > +               pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
>> >> > +                               cpumask_pr_args(policy->related_cpus),
>> >> > +                               cpumask_pr_args(cpus_to_visit));
>> >> > +               cpumask_andnot(cpus_to_visit,
>> >> > +                              cpus_to_visit,
>> >> > +                              policy->related_cpus);
>> >> > +               for_each_cpu(cpu, policy->related_cpus) {
>> >> > +                       raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) *
>> >> > +                                           policy->max / 1000UL;
>> >>
>> >> Should it be policy->cpuinfo.max_freq instead of policy->max ?
>> >>
>> >
>> > Right. I'll fix the arm64 bits as well.
>> >
>> >> > +                       capacity_scale = max(raw_capacity[cpu], capacity_scale);
>> >> > +               }
>> >> > +               if (cpumask_empty(cpus_to_visit)) {
>> >> > +                       normalize_cpu_capacity();
>> >> > +                       kfree(raw_capacity);
>> >> > +                       pr_debug("cpu_capacity: parsing done\n");
>> >> > +                       cap_parsing_done = true;
>> >>
>> >> ok so you do that once with the 1st governor that will be registered
>> >> for the CPU. Can't you unregister the notifier then ?
>> >>
>> >
>> > I tried, but the only place I could find to unregister it is from the
>> > callback itself; and it is not possible to do so AFAIK. Suggestions?
>>
>> yes, you're right
>> Can't you queue a work to unregister your callback ?
>
> You mean something like this? I guess I thought it would be much more
> ugly. :)

Yes something like below.

>
> If it looks OK, I'll add the same for arm64 and test it a bit more.
>
> --->8---
>  arch/arm/kernel/topology.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
> index cbc57c287145..672ae22e2768 100644
> --- a/arch/arm/kernel/topology.c
> +++ b/arch/arm/kernel/topology.c
> @@ -215,7 +215,8 @@ static void normalize_cpu_capacity(void)
>
>  #ifdef CONFIG_CPU_FREQ
>  static cpumask_var_t cpus_to_visit;
> -static bool cap_parsing_done;
> +static void parsing_done_workfn(struct work_struct *work);
> +static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
>
>  static int
>  init_cpu_capacity_callback(struct notifier_block *nb,
> @@ -225,7 +226,7 @@ init_cpu_capacity_callback(struct notifier_block *nb,
>         struct cpufreq_policy *policy = data;
>         int cpu;
>
> -       if (cap_parsing_failed || cap_parsing_done)
> +       if (cap_parsing_failed)

you probably need to keep cap_parsing_done to prevent spurious
notification until the work is scheduled

>                 return 0;
>
>         switch (val) {
> @@ -245,7 +246,7 @@ init_cpu_capacity_callback(struct notifier_block *nb,
>                         normalize_cpu_capacity();
>                         kfree(raw_capacity);
>                         pr_debug("cpu_capacity: parsing done\n");
> -                       cap_parsing_done = true;
> +                       schedule_work(&parsing_done_work);
>                 }
>         }
>         return 0;
> @@ -270,6 +271,13 @@ static int __init register_cpufreq_notifier(void)
>                                          CPUFREQ_POLICY_NOTIFIER);
>  }
>  core_initcall(register_cpufreq_notifier);
> +
> +static void parsing_done_workfn(struct work_struct *work)
> +{
> +       cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
> +                                        CPUFREQ_POLICY_NOTIFIER);
> +}
> +
>  #else
>  static int __init free_raw_capacity(void)
>  {

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#1474184

On 01/09/16 10:22, Vincent Guittot wrote:
> On 31 August 2016 at 19:08, Juri Lelli <juri.lelli@arm.com> wrote:
> > On 31/08/16 10:14, Vincent Guittot wrote:
> >> On 30 August 2016 at 18:28, Juri Lelli <juri.lelli@arm.com> wrote:
> >> > Hi Vincent,
> >> >
> >> > On 16/08/16 10:20, Vincent Guittot wrote:
> >> >> Hi Juri,
> >> >>
> >> >>
> >> >> On 19 July 2016 at 14:40, Juri Lelli <juri.lelli@arm.com> wrote:
> >> >
> >> > [...]
> >> >
> >> >> > +static int
> >> >> > +init_cpu_capacity_callback(struct notifier_block *nb,
> >> >> > +                          unsigned long val,
> >> >> > +                          void *data)
> >> >> > +{
> >> >> > +       struct cpufreq_policy *policy = data;
> >> >> > +       int cpu;
> >> >> > +
> >> >> > +       if (cap_parsing_failed || cap_parsing_done)
> >> >> > +               return 0;
> >> >> > +
> >> >> > +       switch (val) {
> >> >> > +       case CPUFREQ_NOTIFY:
> >> >> > +               pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
> >> >> > +                               cpumask_pr_args(policy->related_cpus),
> >> >> > +                               cpumask_pr_args(cpus_to_visit));
> >> >> > +               cpumask_andnot(cpus_to_visit,
> >> >> > +                              cpus_to_visit,
> >> >> > +                              policy->related_cpus);
> >> >> > +               for_each_cpu(cpu, policy->related_cpus) {
> >> >> > +                       raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) *
> >> >> > +                                           policy->max / 1000UL;
> >> >>
> >> >> Should it be policy->cpuinfo.max_freq instead of policy->max ?
> >> >>
> >> >
> >> > Right. I'll fix the arm64 bits as well.
> >> >
> >> >> > +                       capacity_scale = max(raw_capacity[cpu], capacity_scale);
> >> >> > +               }
> >> >> > +               if (cpumask_empty(cpus_to_visit)) {
> >> >> > +                       normalize_cpu_capacity();
> >> >> > +                       kfree(raw_capacity);
> >> >> > +                       pr_debug("cpu_capacity: parsing done\n");
> >> >> > +                       cap_parsing_done = true;
> >> >>
> >> >> ok so you do that once with the 1st governor that will be registered
> >> >> for the CPU. Can't you unregister the notifier then ?
> >> >>
> >> >
> >> > I tried, but the only place I could find to unregister it is from the
> >> > callback itself; and it is not possible to do so AFAIK. Suggestions?
> >>
> >> yes, you're right
> >> Can't you queue a work to unregister your callback ?
> >
> > You mean something like this? I guess I thought it would be much more
> > ugly. :)
> 
> Yes something like below.
> 
> >
> > If it looks OK, I'll add the same for arm64 and test it a bit more.
> >
> > --->8---
> >  arch/arm/kernel/topology.c | 14 +++++++++++---
> >  1 file changed, 11 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
> > index cbc57c287145..672ae22e2768 100644
> > --- a/arch/arm/kernel/topology.c
> > +++ b/arch/arm/kernel/topology.c
> > @@ -215,7 +215,8 @@ static void normalize_cpu_capacity(void)
> >
> >  #ifdef CONFIG_CPU_FREQ
> >  static cpumask_var_t cpus_to_visit;
> > -static bool cap_parsing_done;
> > +static void parsing_done_workfn(struct work_struct *work);
> > +static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
> >
> >  static int
> >  init_cpu_capacity_callback(struct notifier_block *nb,
> > @@ -225,7 +226,7 @@ init_cpu_capacity_callback(struct notifier_block *nb,
> >         struct cpufreq_policy *policy = data;
> >         int cpu;
> >
> > -       if (cap_parsing_failed || cap_parsing_done)
> > +       if (cap_parsing_failed)
> 
> you probably need to keep cap_parsing_done to prevent spurious
> notification until the work is scheduled
> 

OK. Thanks.

Best,

- Juri

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