Commit 20b5324d authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki
Browse files

cpufreq: optimize cpufreq_notify_transition() 



cpufreq_notify_transition() calls __cpufreq_notify_transition() for each
CPU of a policy. There is a lot of code in __cpufreq_notify_transition()
though which isn't required to be executed for each CPU, like checking
about disabled cpufreq or irqs, adjusting jiffies, updating cpufreq
stats and some debug print messages.

This commit merges __cpufreq_notify_transition() into
cpufreq_notify_transition() and modifies cpufreq_notify_transition() to
execute minimum amount of code for each CPU.

Also fix the kerneldoc for cpufreq_notify_transition() while at it.

Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 130fccd0

drivers/cpufreq/cpufreq.c

+32 −31
Original line number Diff line number Diff line
@@ -300,8 +300,19 @@ static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) 
#endif

}



static void __cpufreq_notify_transition(struct cpufreq_policy *policy,

		struct cpufreq_freqs *freqs, unsigned int state)

/**

 * cpufreq_notify_transition - Notify frequency transition and adjust_jiffies.

 * @policy: cpufreq policy to enable fast frequency switching for.

 * @freqs: contain details of the frequency update.

 * @state: set to CPUFREQ_PRECHANGE or CPUFREQ_POSTCHANGE.

 *

 * This function calls the transition notifiers and the "adjust_jiffies"

 * function. It is called twice on all CPU frequency changes that have

 * external effects.

 */

static void cpufreq_notify_transition(struct cpufreq_policy *policy,

				      struct cpufreq_freqs *freqs,

				      unsigned int state)

{

	BUG_ON(irqs_disabled());
@@ -313,52 +324,42 @@ static void __cpufreq_notify_transition(struct cpufreq_policy *policy, 
		 state, freqs->new);



	switch (state) {



	case CPUFREQ_PRECHANGE:

		/* detect if the driver reported a value as "old frequency"

		/*

		 * Detect if the driver reported a value as "old frequency"

		 * which is not equal to what the cpufreq core thinks is

		 * "old frequency".

		 */

		if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {

			if ((policy) && (policy->cpu == freqs->cpu) &&

			    (policy->cur) && (policy->cur != freqs->old)) {

			if (policy->cur && (policy->cur != freqs->old)) {

				pr_debug("Warning: CPU frequency is %u, cpufreq assumed %u kHz\n",

					 freqs->old, policy->cur);

				freqs->old = policy->cur;

			}

		}



		for_each_cpu(freqs->cpu, policy->cpus) {

			srcu_notifier_call_chain(&cpufreq_transition_notifier_list,

						 CPUFREQ_PRECHANGE, freqs);

		}



		adjust_jiffies(CPUFREQ_PRECHANGE, freqs);

		break;



	case CPUFREQ_POSTCHANGE:

		adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);

		pr_debug("FREQ: %lu - CPU: %lu\n",

			 (unsigned long)freqs->new, (unsigned long)freqs->cpu);

		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);

		cpufreq_stats_record_transition(policy, freqs->new);

			srcu_notifier_call_chain(&cpufreq_transition_notifier_list,

						 CPUFREQ_POSTCHANGE, freqs);

		if (likely(policy) && likely(policy->cpu == freqs->cpu))

			policy->cur = freqs->new;

		break;

	}

		}



/**

 * cpufreq_notify_transition - call notifier chain and adjust_jiffies

 * on frequency transition.

 *

 * This function calls the transition notifiers and the "adjust_jiffies"

 * function. It is called twice on all CPU frequency changes that have

 * external effects.

 */

static void cpufreq_notify_transition(struct cpufreq_policy *policy,

		struct cpufreq_freqs *freqs, unsigned int state)

{

	for_each_cpu(freqs->cpu, policy->cpus)

		__cpufreq_notify_transition(policy, freqs, state);

		cpufreq_stats_record_transition(policy, freqs->new);

		policy->cur = freqs->new;

	}

}



/* Do post notifications when there are chances that transition has failed */

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