Re: [PATCH v6 2/8] arm: parse cpu capacity-dmips-mhz from DT
From: Vincent Guittot <vincent.guittot@linaro.org>
Date: 2016-09-01 08:22:59
Also in:
linux-arm-kernel, linux-pm, lkml
On 31 August 2016 at 19:08, Juri Lelli [off-list ref] wrote:
On 31/08/16 10:14, Vincent Guittot wrote:quoted
On 30 August 2016 at 18:28, Juri Lelli [off-list ref] wrote:quoted
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 ?You mean something like this? I guess I thought it would be much more ugly. :)
Yes something like below.
quoted hunk ↗ jump to hunk
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
quoted hunk ↗ jump to hunk
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) {