[wake_afine fixes/improvements 2/3] sched: clean up task_hot()

[Paul Turner <pjt@google.com>]

[-- Attachment #1: no_hot_sd.patch --]
[-- Type: text/plain, Size: 3081 bytes --]

We no longer compute per-domain migration costs or have use for task_hot()
external to the fair scheduling class.

Signed-off-by: Paul Turner <pjt@google.com>

---
 kernel/sched.c      |   35 -----------------------------------
 kernel/sched_fair.c |   32 +++++++++++++++++++++++++++++++-
 2 files changed, 31 insertions(+), 36 deletions(-)

Index: tip3/kernel/sched.c
===================================================================
--- tip3.orig/kernel/sched.c
+++ tip3/kernel/sched.c
@@ -1522,8 +1522,6 @@ static unsigned long power_of(int cpu)
 	return cpu_rq(cpu)->cpu_power;
 }
 
-static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
-
 static unsigned long cpu_avg_load_per_task(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
@@ -2061,38 +2059,6 @@ static void check_preempt_curr(struct rq
 }
 
 #ifdef CONFIG_SMP
-/*
- * Is this task likely cache-hot:
- */
-static int
-task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
-{
-	s64 delta;
-
-	if (p->sched_class != &fair_sched_class)
-		return 0;
-
-	if (unlikely(p->policy == SCHED_IDLE))
-		return 0;
-
-	/*
-	 * Buddy candidates are cache hot:
-	 */
-	if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running &&
-			(&p->se == cfs_rq_of(&p->se)->next ||
-			 &p->se == cfs_rq_of(&p->se)->last))
-		return 1;
-
-	if (sysctl_sched_migration_cost == -1)
-		return 1;
-	if (sysctl_sched_migration_cost == 0)
-		return 0;
-
-	delta = now - p->se.exec_start;
-
-	return delta < (s64)sysctl_sched_migration_cost;
-}
-
 void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
 {
 #ifdef CONFIG_SCHED_DEBUG
@@ -9237,4 +9203,3 @@ struct cgroup_subsys cpuacct_subsys = {
 	.subsys_id = cpuacct_subsys_id,
 };
 #endif	/* CONFIG_CGROUP_CPUACCT */
-
Index: tip3/kernel/sched_fair.c
===================================================================
--- tip3.orig/kernel/sched_fair.c
+++ tip3/kernel/sched_fair.c
@@ -1346,6 +1346,36 @@ static void task_waking_fair(struct rq *
 	se->vruntime -= cfs_rq->min_vruntime;
 }
 
+/* is this task likely cache-hot */
+static int
+task_hot(struct task_struct *p, u64 now)
+{
+	s64 delta;
+
+	if (p->sched_class != &fair_sched_class)
+		return 0;
+
+	if (unlikely(p->policy == SCHED_IDLE))
+		return 0;
+
+	/*
+	 * Buddy candidates are cache hot:
+	 */
+	if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running &&
+			(&p->se == cfs_rq_of(&p->se)->next ||
+			 &p->se == cfs_rq_of(&p->se)->last))
+		return 1;
+
+	if (sysctl_sched_migration_cost == -1)
+		return 1;
+	if (sysctl_sched_migration_cost == 0)
+		return 0;
+
+	delta = now - p->se.exec_start;
+
+	return delta < (s64)sysctl_sched_migration_cost;
+}
+
 #ifdef CONFIG_FAIR_GROUP_SCHED
 /*
  * effective_load() calculates the load change as seen from the root_task_group
@@ -1954,7 +1984,7 @@ int can_migrate_task(struct task_struct 
 	 * 2) too many balance attempts have failed.
 	 */
 
-	tsk_cache_hot = task_hot(p, rq->clock_task, sd);
+	tsk_cache_hot = task_hot(p, rq->clock_task);
 	if (!tsk_cache_hot ||
 		sd->nr_balance_failed > sd->cache_nice_tries) {
 #ifdef CONFIG_SCHEDSTATS