linux-kernel - [PATCH 3/4] sched: export get_cpu_usage & capacity_orig

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Date:	Mon,  4 May 2015 15:10:40 -0700
From:	Michael Turquette <mturquette@...aro.org>
To:	peterz@...radead.org, mingo@...nel.org
Cc:	linux-kernel@...r.kernel.org, preeti@...ux.vnet.ibm.com,
	Morten.Rasmussen@....com, riel@...hat.com, efault@....de,
	nicolas.pitre@...aro.org, inaro-kernel@...ts.linaro.org,
	daniel.lezcano@...aro.org, patches@...aro.org,
	eas-dev@...ts.linaro.org, dietmar.eggemann@....com,
	vincent.guittot@...aro.org, amit.kucheria@...aro.org,
	juri.lelli@....com, rjw@...ysocki.net, viresh.kumar@...aro.org,
	ashwin.chaugule@...aro.org, alex.shi@...aro.org,
	Michael Turquette <mturquette@...aro.org>
Subject: [PATCH 3/4] sched: export get_cpu_usage & capacity_orig_of

get_cpu_usage and capacity_orig_of are useful for a cpu frequency
scaling policy which is based on cfs load tracking and cpu capacity
metrics. Expose these calls in sched.h so that they can be used in such
a policy.

Signed-off-by: Michael Turquette <mturquette@...aro.org>
---
 kernel/sched/fair.c  | 32 --------------------------------
 kernel/sched/sched.h | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 32 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 75aec8d..9e37d49 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4366,11 +4366,6 @@ static unsigned long capacity_of(int cpu)
 	return cpu_rq(cpu)->cpu_capacity;
 }
 
-static unsigned long capacity_orig_of(int cpu)
-{
-	return cpu_rq(cpu)->cpu_capacity_orig;
-}
-
 static unsigned long cpu_avg_load_per_task(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
@@ -4784,33 +4779,6 @@ next:
 done:
 	return target;
 }
-/*
- * get_cpu_usage returns the amount of capacity of a CPU that is used by CFS
- * tasks. The unit of the return value must be the one of capacity so we can
- * compare the usage with the capacity of the CPU that is available for CFS
- * task (ie cpu_capacity).
- * cfs.utilization_load_avg is the sum of running time of runnable tasks on a
- * CPU. It represents the amount of utilization of a CPU in the range
- * [0..SCHED_LOAD_SCALE].  The usage of a CPU can't be higher than the full
- * capacity of the CPU because it's about the running time on this CPU.
- * Nevertheless, cfs.utilization_load_avg can be higher than SCHED_LOAD_SCALE
- * because of unfortunate rounding in avg_period and running_load_avg or just
- * after migrating tasks until the average stabilizes with the new running
- * time. So we need to check that the usage stays into the range
- * [0..cpu_capacity_orig] and cap if necessary.
- * Without capping the usage, a group could be seen as overloaded (CPU0 usage
- * at 121% + CPU1 usage at 80%) whereas CPU1 has 20% of available capacity
- */
-static int get_cpu_usage(int cpu)
-{
-	unsigned long usage = cpu_rq(cpu)->cfs.utilization_load_avg;
-	unsigned long capacity = capacity_orig_of(cpu);
-
-	if (usage >= SCHED_LOAD_SCALE)
-		return capacity;
-
-	return (usage * capacity) >> SCHED_LOAD_SHIFT;
-}
 
 /*
  * select_task_rq_fair: Select target runqueue for the waking task in domains
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index e0e1299..8bf35d3 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1396,6 +1396,39 @@ unsigned long arch_scale_freq_capacity(struct sched_domain *sd, int cpu)
 }
 #endif
 
+static inline unsigned long capacity_orig_of(int cpu)
+{
+	return cpu_rq(cpu)->cpu_capacity_orig;
+}
+
+/*
+ * get_cpu_usage returns the amount of capacity of a CPU that is used by CFS
+ * tasks. The unit of the return value must be the one of capacity so we can
+ * compare the usage with the capacity of the CPU that is available for CFS
+ * task (ie cpu_capacity).
+ * cfs.utilization_load_avg is the sum of running time of runnable tasks on a
+ * CPU. It represents the amount of utilization of a CPU in the range
+ * [0..SCHED_LOAD_SCALE].  The usage of a CPU can't be higher than the full
+ * capacity of the CPU because it's about the running time on this CPU.
+ * Nevertheless, cfs.utilization_load_avg can be higher than SCHED_LOAD_SCALE
+ * because of unfortunate rounding in avg_period and running_load_avg or just
+ * after migrating tasks until the average stabilizes with the new running
+ * time. So we need to check that the usage stays into the range
+ * [0..cpu_capacity_orig] and cap if necessary.
+ * Without capping the usage, a group could be seen as overloaded (CPU0 usage
+ * at 121% + CPU1 usage at 80%) whereas CPU1 has 20% of available capacity
+ */
+static inline int get_cpu_usage(int cpu)
+{
+	unsigned long usage = cpu_rq(cpu)->cfs.utilization_load_avg;
+	unsigned long capacity = capacity_orig_of(cpu);
+
+	if (usage >= SCHED_LOAD_SCALE)
+		return capacity;
+
+	return (usage * capacity) >> SCHED_LOAD_SHIFT;
+}
+
 static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
 {
 	rq->rt_avg += rt_delta * arch_scale_freq_capacity(NULL, cpu_of(rq));
-- 
1.9.1

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