linux-kernel - [PATCH v2 2/2] cpufreq / sched: Pass runqueue pointer to cpufreq_update

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Date:	Fri, 12 Aug 2016 02:06:44 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Linux PM list <linux-pm@...r.kernel.org>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Steve Muckle <steve.muckle@...aro.org>,
	Juri Lelli <juri.lelli@....com>, Ingo Molnar <mingo@...nel.org>
Subject: [PATCH v2 2/2] cpufreq / sched: Pass runqueue pointer to cpufreq_update_util()

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

All of the callers of cpufreq_update_util() pass rq_clock(rq) to it
as the time argument and some of them check whether or not cpu_of(rq)
is equal to smp_processor_id() before calling it, so rework it to
take a runqueue pointer as the argument and move the rq_clock(rq)
evaluation into it.

Additionally, provide a wrapper checking cpu_of(rq) against
smp_processor_id() for the cpufreq_update_util() callers that
need it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---

This is a new patch based on the [2/2] from v1.

---
 kernel/sched/deadline.c |    3 +--
 kernel/sched/fair.c     |    4 +---
 kernel/sched/rt.c       |    3 +--
 kernel/sched/sched.h    |   15 +++++++++++----
 4 files changed, 14 insertions(+), 11 deletions(-)

Index: linux-pm/kernel/sched/deadline.c
===================================================================
--- linux-pm.orig/kernel/sched/deadline.c
+++ linux-pm/kernel/sched/deadline.c
@@ -733,8 +733,7 @@ static void update_curr_dl(struct rq *rq
 	}
 
 	/* kick cpufreq (see the comment in kernel/sched/sched.h). */
-	if (cpu_of(rq) == smp_processor_id())
-		cpufreq_update_util(rq_clock(rq), SCHED_CPUFREQ_DL);
+	cpufreq_update_this_cpu(rq, SCHED_CPUFREQ_DL);
 
 	schedstat_set(curr->se.statistics.exec_max,
 		      max(curr->se.statistics.exec_max, delta_exec));
Index: linux-pm/kernel/sched/fair.c
===================================================================
--- linux-pm.orig/kernel/sched/fair.c
+++ linux-pm/kernel/sched/fair.c
@@ -2876,8 +2876,6 @@ static inline void update_tg_load_avg(st
 static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq)
 {
 	if (&this_rq()->cfs == cfs_rq) {
-		struct rq *rq = rq_of(cfs_rq);
-
 		/*
 		 * There are a few boundary cases this might miss but it should
 		 * get called often enough that that should (hopefully) not be
@@ -2894,7 +2892,7 @@ static inline void cfs_rq_util_change(st
 		 *
 		 * See cpu_util().
 		 */
-		cpufreq_update_util(rq_clock(rq), 0);
+		cpufreq_update_util(rq_of(cfs_rq), 0);
 	}
 }
 
Index: linux-pm/kernel/sched/rt.c
===================================================================
--- linux-pm.orig/kernel/sched/rt.c
+++ linux-pm/kernel/sched/rt.c
@@ -958,8 +958,7 @@ static void update_curr_rt(struct rq *rq
 		return;
 
 	/* Kick cpufreq (see the comment in kernel/sched/sched.h). */
-	if (cpu_of(rq) == smp_processor_id())
-		cpufreq_update_util(rq_clock(rq), SCHED_CPUFREQ_RT);
+	cpufreq_update_this_cpu(rq, SCHED_CPUFREQ_RT);
 
 	schedstat_set(curr->se.statistics.exec_max,
 		      max(curr->se.statistics.exec_max, delta_exec));
Index: linux-pm/kernel/sched/sched.h
===================================================================
--- linux-pm.orig/kernel/sched/sched.h
+++ linux-pm/kernel/sched/sched.h
@@ -1763,7 +1763,7 @@ DECLARE_PER_CPU(struct update_util_data
 
 /**
  * cpufreq_update_util - Take a note about CPU utilization changes.
- * @time: Current time.
+ * @rq: Runqueue to carry out the update for.
  * @flags: Update reason flags.
  *
  * This function is called by the scheduler on the CPU whose utilization is
@@ -1783,16 +1783,23 @@ DECLARE_PER_CPU(struct update_util_data
  * but that really is a band-aid.  Going forward it should be replaced with
  * solutions targeted more specifically at RT and DL tasks.
  */
-static inline void cpufreq_update_util(u64 time, unsigned int flags)
+static inline void cpufreq_update_util(struct rq *rq, unsigned int flags)
 {
 	struct update_util_data *data;
 
 	data = rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data));
 	if (data)
-		data->func(data, time, flags);
+		data->func(data, rq_clock(rq), flags);
+}
+
+static inline void cpufreq_update_this_cpu(struct rq *rq, unsigned int flags)
+{
+	if (cpu_of(rq) == smp_processor_id())
+		cpufreq_update_util(rq, flags);
 }
 #else
-static inline void cpufreq_update_util(u64 time, unsigned int flags) {}
+static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
+static inline void cpufreq_update_this_cpu(struct rq *rq, unsigned int flags) {}
 #endif /* CONFIG_CPU_FREQ */
 
 #ifdef arch_scale_freq_capacity