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authorViresh Kumar <viresh.kumar@linaro.org>2019-04-29 15:03:58 +0530
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-05-10 12:20:36 +0200
commitdf24014abe3694e7c34ce5e50248611b7a93fe83 (patch)
tree98d5dc569e611f1cffec3a5c7bfeb66097c01283 /drivers/cpufreq
parent8f5e823f9131a430b12f73e9436d7486e20c16f5 (diff)
cpufreq: Call transition notifier only once for each policy
Currently, the notifiers are called once for each CPU of the policy->cpus cpumask. It would be more optimal if the notifier can be called only once and all the relevant information be provided to it. Out of the 23 drivers that register for the transition notifiers today, only 4 of them do per-cpu updates and the callback for the rest can be called only once for the policy without any impact. This would also avoid multiple function calls to the notifier callbacks and reduce multiple iterations of notifier core's code (which does locking as well). This patch adds pointer to the cpufreq policy to the struct cpufreq_freqs, so the notifier callback has all the information available to it with a single call. The five drivers which perform per-cpu updates are updated to use the cpufreq policy. The freqs->cpu field is redundant now and is removed. Acked-by: David S. Miller <davem@davemloft.net> (sparc) Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cpufreq.c19
1 files changed, 10 insertions, 9 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 7ea217c88c2e..c66eefe928c5 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -340,11 +340,14 @@ static void cpufreq_notify_transition(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs,
unsigned int state)
{
+ int cpu;
+
BUG_ON(irqs_disabled());
if (cpufreq_disabled())
return;
+ freqs->policy = policy;
freqs->flags = cpufreq_driver->flags;
pr_debug("notification %u of frequency transition to %u kHz\n",
state, freqs->new);
@@ -364,10 +367,8 @@ static void cpufreq_notify_transition(struct cpufreq_policy *policy,
}
}
- for_each_cpu(freqs->cpu, policy->cpus) {
- srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
- CPUFREQ_PRECHANGE, freqs);
- }
+ srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
+ CPUFREQ_PRECHANGE, freqs);
adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
break;
@@ -377,11 +378,11 @@ static void cpufreq_notify_transition(struct cpufreq_policy *policy,
pr_debug("FREQ: %u - CPUs: %*pbl\n", freqs->new,
cpumask_pr_args(policy->cpus));
- for_each_cpu(freqs->cpu, policy->cpus) {
- trace_cpu_frequency(freqs->new, freqs->cpu);
- srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
- CPUFREQ_POSTCHANGE, freqs);
- }
+ for_each_cpu(cpu, policy->cpus)
+ trace_cpu_frequency(freqs->new, cpu);
+
+ srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
+ CPUFREQ_POSTCHANGE, freqs);
cpufreq_stats_record_transition(policy, freqs->new);
policy->cur = freqs->new;