From: Dietmar Eggemann <dietmar.eggemann@arm.com>
Date: Mon, 5 Dec 2016 14:15:54 +0000 (+0000)
Subject: EAS: sched/fair: Re-integrate 'honor sync wakeups' into wakeup path
X-Git-Tag: release-20171130_firefly~4^2~100^2~55
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e89e4bb2be584bc559b0d0238d4dffc8db5caf07;p=firefly-linux-kernel-4.4.55.git

EAS: sched/fair: Re-integrate 'honor sync wakeups' into wakeup path

This patch re-integrates the part which was initially provided by
3b9d7554aeec ("EAS: sched/fair: tunable to honor sync wakeups") into
energy_aware_wake_cpu() into select_energy_cpu_brute().

Change-Id: I748fde3ecdeb44651179bce0a5bb8dd82d1903f6
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
(cherry picked from commit b75b7286cb068d5761621ea134c23dd131db953f)
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
---

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ae3cc8df331c..5e4bf1e76275 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5889,13 +5889,21 @@ static int wake_cap(struct task_struct *p, int cpu, int prev_cpu)
 	return min_cap * 1024 < task_util(p) * capacity_margin;
 }
 
-static int select_energy_cpu_brute(struct task_struct *p, int prev_cpu)
+static int select_energy_cpu_brute(struct task_struct *p, int prev_cpu, int sync)
 {
 	int i;
 	int min_diff = 0, energy_cpu = prev_cpu, spare_cpu = prev_cpu;
 	unsigned long max_spare = 0;
 	struct sched_domain *sd;
 
+	if (sysctl_sched_sync_hint_enable && sync) {
+		int cpu = smp_processor_id();
+		cpumask_t search_cpus;
+		cpumask_and(&search_cpus, tsk_cpus_allowed(p), cpu_online_mask);
+		if (cpumask_test_cpu(cpu, &search_cpus))
+			return cpu;
+	}
+
 	rcu_read_lock();
 
 	sd = rcu_dereference(per_cpu(sd_ea, prev_cpu));
@@ -5970,7 +5978,7 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
 			      && cpumask_test_cpu(cpu, tsk_cpus_allowed(p));
 
 	if (energy_aware() && !(cpu_rq(prev_cpu)->rd->overutilized))
-		return select_energy_cpu_brute(p, prev_cpu);
+		return select_energy_cpu_brute(p, prev_cpu, sync);
 
 	rcu_read_lock();
 	for_each_domain(cpu, tmp) {