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