From 8875125efe8402c4d84b08291e68f1281baba8e2 Mon Sep 17 00:00:00 2001
From: Kirill Tkhai <tkhai@yandex.ru>
Date: Sun, 29 Jun 2014 00:03:57 +0400
Subject: sched: Transform resched_task() into resched_curr()

We always use resched_task() with rq->curr argument.
It's not possible to reschedule any task but rq's current.

The patch introduces resched_curr(struct rq *) to
replace all of the repeating patterns. The main aim
is cleanup, but there is a little size profit too:

  (before)
	$ size kernel/sched/built-in.o
	   text	   data	    bss	    dec	    hex	filename
	155274	  16445	   7042	 178761	  2ba49	kernel/sched/built-in.o

	$ size vmlinux
	   text	   data	    bss	    dec	    hex	filename
	7411490	1178376	 991232	9581098	 92322a	vmlinux

  (after)
	$ size kernel/sched/built-in.o
	   text	   data	    bss	    dec	    hex	filename
	155130	  16445	   7042	 178617	  2b9b9	kernel/sched/built-in.o

	$ size vmlinux
	   text	   data	    bss	    dec	    hex	filename
	7411362	1178376	 991232	9580970	 9231aa	vmlinux

	I was choosing between resched_curr() and resched_rq(),
	and the first name looks better for me.

A little lie in Documentation/trace/ftrace.txt. I have not
actually collected the tracing again. With a hope the patch
won't make execution times much worse :)

Signed-off-by: Kirill Tkhai <tkhai@yandex.ru>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20140628200219.1778.18735.stgit@localhost
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/rt.c | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

(limited to 'kernel/sched/rt.c')

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 671a8b5fdb6f..5f6edca4fafd 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -463,9 +463,10 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se);
 static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
 {
 	struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
+	struct rq *rq = rq_of_rt_rq(rt_rq);
 	struct sched_rt_entity *rt_se;
 
-	int cpu = cpu_of(rq_of_rt_rq(rt_rq));
+	int cpu = cpu_of(rq);
 
 	rt_se = rt_rq->tg->rt_se[cpu];
 
@@ -476,7 +477,7 @@ static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
 			enqueue_rt_entity(rt_se, false);
 
 		if (rt_rq->highest_prio.curr < curr->prio)
-			resched_task(curr);
+			resched_curr(rq);
 	}
 }
 
@@ -566,7 +567,7 @@ static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
 		return;
 
 	enqueue_top_rt_rq(rt_rq);
-	resched_task(rq->curr);
+	resched_curr(rq);
 }
 
 static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
@@ -951,7 +952,7 @@ static void update_curr_rt(struct rq *rq)
 			raw_spin_lock(&rt_rq->rt_runtime_lock);
 			rt_rq->rt_time += delta_exec;
 			if (sched_rt_runtime_exceeded(rt_rq))
-				resched_task(curr);
+				resched_curr(rq);
 			raw_spin_unlock(&rt_rq->rt_runtime_lock);
 		}
 	}
@@ -1366,7 +1367,7 @@ static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
 	 * to try and push current away:
 	 */
 	requeue_task_rt(rq, p, 1);
-	resched_task(rq->curr);
+	resched_curr(rq);
 }
 
 #endif /* CONFIG_SMP */
@@ -1377,7 +1378,7 @@ static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
 static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags)
 {
 	if (p->prio < rq->curr->prio) {
-		resched_task(rq->curr);
+		resched_curr(rq);
 		return;
 	}
 
@@ -1693,7 +1694,7 @@ retry:
 	 * just reschedule current.
 	 */
 	if (unlikely(next_task->prio < rq->curr->prio)) {
-		resched_task(rq->curr);
+		resched_curr(rq);
 		return 0;
 	}
 
@@ -1740,7 +1741,7 @@ retry:
 	activate_task(lowest_rq, next_task, 0);
 	ret = 1;
 
-	resched_task(lowest_rq->curr);
+	resched_curr(lowest_rq);
 
 	double_unlock_balance(rq, lowest_rq);
 
@@ -1939,7 +1940,7 @@ static void switched_from_rt(struct rq *rq, struct task_struct *p)
 		return;
 
 	if (pull_rt_task(rq))
-		resched_task(rq->curr);
+		resched_curr(rq);
 }
 
 void __init init_sched_rt_class(void)
@@ -1977,7 +1978,7 @@ static void switched_to_rt(struct rq *rq, struct task_struct *p)
 			check_resched = 0;
 #endif /* CONFIG_SMP */
 		if (check_resched && p->prio < rq->curr->prio)
-			resched_task(rq->curr);
+			resched_curr(rq);
 	}
 }
 
@@ -2006,11 +2007,11 @@ prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
 		 * Only reschedule if p is still on the same runqueue.
 		 */
 		if (p->prio > rq->rt.highest_prio.curr && rq->curr == p)
-			resched_task(p);
+			resched_curr(rq);
 #else
 		/* For UP simply resched on drop of prio */
 		if (oldprio < p->prio)
-			resched_task(p);
+			resched_curr(rq);
 #endif /* CONFIG_SMP */
 	} else {
 		/*
@@ -2019,7 +2020,7 @@ prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
 		 * then reschedule.
 		 */
 		if (p->prio < rq->curr->prio)
-			resched_task(rq->curr);
+			resched_curr(rq);
 	}
 }
 
-- 
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