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

On 30 August 2016 at 18:28, Juri Lelli [off-list ref] wrote:

Hi Vincent,

On 16/08/16 10:20, Vincent Guittot wrote:

quoted

Hi Juri,


On 19 July 2016 at 14:40, Juri Lelli [off-list ref] wrote:

[...]

quoted

quoted

+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.

quoted

quoted

+                       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