linux-kernel - [PATCH] sched: Create task_has_idle

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Date:   Mon,  5 Nov 2018 16:51:55 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Viresh Kumar <viresh.kumar@...aro.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] sched: Create task_has_idle_policy() helper

We already have task_has_rt_policy() and task_has_dl_policy() helpers,
create task_has_idle_policy() as well and update sched core to start
using it.

While at it, use task_has_dl_policy() at one more place.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 kernel/sched/core.c  |  4 ++--
 kernel/sched/debug.c |  2 +-
 kernel/sched/fair.c  | 10 +++++-----
 kernel/sched/sched.h |  5 +++++
 4 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index f12225f26b70..841f4e16c157 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -697,7 +697,7 @@ static void set_load_weight(struct task_struct *p, bool update_load)
 	/*
 	 * SCHED_IDLE tasks get minimal weight:
 	 */
-	if (idle_policy(p->policy)) {
+	if (task_has_idle_policy(p)) {
 		load->weight = scale_load(WEIGHT_IDLEPRIO);
 		load->inv_weight = WMULT_IDLEPRIO;
 		p->se.runnable_weight = load->weight;
@@ -4191,7 +4191,7 @@ static int __sched_setscheduler(struct task_struct *p,
 		 * Treat SCHED_IDLE as nice 20. Only allow a switch to
 		 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
 		 */
-		if (idle_policy(p->policy) && !idle_policy(policy)) {
+		if (task_has_idle_policy(p) && !idle_policy(policy)) {
 			if (!can_nice(p, task_nice(p)))
 				return -EPERM;
 		}
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 6383aa6a60ca..02bd5f969b21 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -974,7 +974,7 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
 #endif
 	P(policy);
 	P(prio);
-	if (p->policy == SCHED_DEADLINE) {
+	if (task_has_dl_policy(p)) {
 		P(dl.runtime);
 		P(dl.deadline);
 	}
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ee271bb661cc..1c8776175235 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6486,7 +6486,7 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
 
 static void set_last_buddy(struct sched_entity *se)
 {
-	if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE))
+	if (entity_is_task(se) && unlikely(task_has_idle_policy(task_of(se))))
 		return;
 
 	for_each_sched_entity(se) {
@@ -6498,7 +6498,7 @@ static void set_last_buddy(struct sched_entity *se)
 
 static void set_next_buddy(struct sched_entity *se)
 {
-	if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE))
+	if (entity_is_task(se) && unlikely(task_has_idle_policy(task_of(se))))
 		return;
 
 	for_each_sched_entity(se) {
@@ -6556,8 +6556,8 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
 		return;
 
 	/* Idle tasks are by definition preempted by non-idle tasks. */
-	if (unlikely(curr->policy == SCHED_IDLE) &&
-	    likely(p->policy != SCHED_IDLE))
+	if (unlikely(task_has_idle_policy(curr)) &&
+	    likely(!task_has_idle_policy(p)))
 		goto preempt;
 
 	/*
@@ -6978,7 +6978,7 @@ static int task_hot(struct task_struct *p, struct lb_env *env)
 	if (p->sched_class != &fair_sched_class)
 		return 0;
 
-	if (unlikely(p->policy == SCHED_IDLE))
+	if (unlikely(task_has_idle_policy(p)))
 		return 0;
 
 	/*
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 618577fc9aa8..b7a3147874e3 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -176,6 +176,11 @@ static inline bool valid_policy(int policy)
 		rt_policy(policy) || dl_policy(policy);
 }
 
+static inline int task_has_idle_policy(struct task_struct *p)
+{
+	return idle_policy(p->policy);
+}
+
 static inline int task_has_rt_policy(struct task_struct *p)
 {
 	return rt_policy(p->policy);
-- 
2.19.1.568.g152ad8e3369a