From: Dietmar Eggemann <dietmar.eggemann@arm.com>
Date: Thu, 26 Jan 2017 16:04:34 +0000 (+0000)
Subject: sched/fair: Decommission energy_aware_wake_cpu()
X-Git-Tag: release-20171130_firefly~4^2~100^2~59
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=9936e8452a59ef8c30503ddde96cc31e09baa59c;p=firefly-linux-kernel-4.4.55.git

sched/fair: Decommission energy_aware_wake_cpu()

The EAS functionality in the wakeup path will be brought back by the
following patch ("sched/fair: Energy-aware wake-up task placement")
providing the function select_energy_cpu_brute().

Change-Id: I927fb9e8261cfacfe404695f853941c7959aa146
[ Trivial merge conflicts resolved. ]
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
(cherry picked from commit 80aee424fb7765a777267e144037642625a71304)
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
---

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 976e7457b4fa..ef16d4d3cc00 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5836,122 +5836,6 @@ static inline int find_best_target(struct task_struct *p, bool boosted, bool pre
 	return target_cpu;
 }
 
-static int energy_aware_wake_cpu(struct task_struct *p, int target, int sync)
-{
-	struct sched_domain *sd;
-	struct sched_group *sg, *sg_target;
-	int target_max_cap = INT_MAX;
-	int target_cpu = task_cpu(p);
-	unsigned long task_util_boosted, new_util;
-	int i;
-
-	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;
-	}
-
-	sd = rcu_dereference(per_cpu(sd_ea, task_cpu(p)));
-
-	if (!sd)
-		return target;
-
-	sg = sd->groups;
-	sg_target = sg;
-
-	if (sysctl_sched_is_big_little) {
-
-		/*
-		 * Find group with sufficient capacity. We only get here if no cpu is
-		 * overutilized. We may end up overutilizing a cpu by adding the task,
-		 * but that should not be any worse than select_idle_sibling().
-		 * load_balance() should sort it out later as we get above the tipping
-		 * point.
-		 */
-		do {
-			/* Assuming all cpus are the same in group */
-			int max_cap_cpu = group_first_cpu(sg);
-
-			/*
-			 * Assume smaller max capacity means more energy-efficient.
-			 * Ideally we should query the energy model for the right
-			 * answer but it easily ends up in an exhaustive search.
-			 */
-			if (capacity_of(max_cap_cpu) < target_max_cap &&
-			    task_fits_max(p, max_cap_cpu)) {
-				sg_target = sg;
-				target_max_cap = capacity_of(max_cap_cpu);
-			}
-		} while (sg = sg->next, sg != sd->groups);
-
-		task_util_boosted = boosted_task_util(p);
-		/* Find cpu with sufficient capacity */
-		for_each_cpu_and(i, tsk_cpus_allowed(p), sched_group_cpus(sg_target)) {
-			/*
-			 * p's blocked utilization is still accounted for on prev_cpu
-			 * so prev_cpu will receive a negative bias due to the double
-			 * accounting. However, the blocked utilization may be zero.
-			 */
-			new_util = cpu_util(i) + task_util_boosted;
-
-			/*
-			 * Ensure minimum capacity to grant the required boost.
-			 * The target CPU can be already at a capacity level higher
-			 * than the one required to boost the task.
-			 */
-			if (new_util > capacity_orig_of(i))
-				continue;
-
-			if (new_util < capacity_curr_of(i)) {
-				target_cpu = i;
-				if (cpu_rq(i)->nr_running)
-					break;
-			}
-
-			/* cpu has capacity at higher OPP, keep it as fallback */
-			if (target_cpu == task_cpu(p))
-				target_cpu = i;
-		}
-	} else {
-		/*
-		 * Find a cpu with sufficient capacity
-		 */
-#ifdef CONFIG_CGROUP_SCHEDTUNE
-		bool boosted = schedtune_task_boost(p) > 0;
-		bool prefer_idle = schedtune_prefer_idle(p) > 0;
-#else
-		bool boosted = 0;
-		bool prefer_idle = 0;
-#endif
-		int tmp_target = find_best_target(p, boosted, prefer_idle);
-		if (tmp_target >= 0) {
-			target_cpu = tmp_target;
-			if ((boosted || prefer_idle) && idle_cpu(target_cpu))
-				return target_cpu;
-		}
-	}
-
-	if (target_cpu != task_cpu(p)) {
-		struct energy_env eenv = {
-			.util_delta	= task_util(p),
-			.src_cpu	= task_cpu(p),
-			.dst_cpu	= target_cpu,
-			.task		= p,
-		};
-
-		/* Not enough spare capacity on previous cpu */
-		if (cpu_overutilized(task_cpu(p)))
-			return target_cpu;
-
-		if (energy_diff(&eenv) >= 0)
-			return task_cpu(p);
-	}
-
-	return target_cpu;
-}
-
 /*
  * cpu_util_wake: Compute cpu utilization with any contributions from
  * the waking task p removed.
@@ -6047,9 +5931,7 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
 	}
 
 	if (!sd) {
-		if (energy_aware() && !cpu_rq(cpu)->rd->overutilized)
-			new_cpu = energy_aware_wake_cpu(p, prev_cpu, sync);
-		else if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */
+		if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */
 			new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);
 
 	} else while (sd) {