On 31 August 2016 at 19:08, Juri Lelli <juri.lelli@xxxxxxx> wrote:
> On 31/08/16 10:14, Vincent Guittot wrote:
>> On 30 August 2016 at 18:28, Juri Lelli <juri.lelli@xxxxxxx> 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@xxxxxxx> 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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