sched: Make sched_param argument static in sched_setscheduler() callers

Andrew Morton pointed out almost all sched_setscheduler() callers are
using fixed parameters and can be converted to static.  It reduces runtime
memory use a little.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: James Morris <jmorris@namei.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/sched.h

@@ -1942,9 +1942,10 @@ extern int task_nice(const struct task_struct *p);
 extern int can_nice(const struct task_struct *p, const int nice);
 extern int task_curr(const struct task_struct *p);
 extern int idle_cpu(int cpu);
-extern int sched_setscheduler(struct task_struct *, int, struct sched_param *);
+extern int sched_setscheduler(struct task_struct *, int,
+			      const struct sched_param *);
 extern int sched_setscheduler_nocheck(struct task_struct *, int,
-				      struct sched_param *);
+				      const struct sched_param *);
 extern struct task_struct *idle_task(int cpu);
 extern struct task_struct *curr_task(int cpu);
 extern void set_curr_task(int cpu, struct task_struct *p);

kernel/irq/manage.c

@@ -573,7 +573,9 @@ irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
  */
 static int irq_thread(void *data)
 {
-	struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2, };
+	static struct sched_param param = {
+		.sched_priority = MAX_USER_RT_PRIO/2,
+	};
 	struct irqaction *action = data;
 	struct irq_desc *desc = irq_to_desc(action->irq);
 	int wake, oneshot = desc->status & IRQ_ONESHOT;

kernel/kthread.c

@@ -148,7 +148,7 @@ struct task_struct *kthread_create(int (*threadfn)(void *data),
 	wait_for_completion(&create.done);
 
 	if (!IS_ERR(create.result)) {
-		struct sched_param param = { .sched_priority = 0 };
+		static struct sched_param param = { .sched_priority = 0 };
 		va_list args;
 
 		va_start(args, namefmt);

kernel/sched.c

@@ -4701,7 +4701,7 @@ static bool check_same_owner(struct task_struct *p)
 }
 
 static int __sched_setscheduler(struct task_struct *p, int policy,
-				struct sched_param *param, bool user)
+				const struct sched_param *param, bool user)
 {
 	int retval, oldprio, oldpolicy = -1, on_rq, running;
 	unsigned long flags;
@@ -4856,7 +4856,7 @@ recheck:
  * NOTE that the task may be already dead.
  */
 int sched_setscheduler(struct task_struct *p, int policy,
-		       struct sched_param *param)
+		       const struct sched_param *param)
 {
 	return __sched_setscheduler(p, policy, param, true);
 }
@@ -4874,7 +4874,7 @@ EXPORT_SYMBOL_GPL(sched_setscheduler);
  * but our caller might not have that capability.
  */
 int sched_setscheduler_nocheck(struct task_struct *p, int policy,
-			       struct sched_param *param)
+			       const struct sched_param *param)
 {
 	return __sched_setscheduler(p, policy, param, false);
 }

kernel/softirq.c

@@ -851,7 +851,9 @@ static int __cpuinit cpu_callback(struct notifier_block *nfb,
 			     cpumask_any(cpu_online_mask));
 	case CPU_DEAD:
 	case CPU_DEAD_FROZEN: {
-		struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
+		static struct sched_param param = {
+			.sched_priority = MAX_RT_PRIO-1
+		};
 
 		p = per_cpu(ksoftirqd, hotcpu);
 		per_cpu(ksoftirqd, hotcpu) = NULL;

kernel/trace/trace_selftest.c

@@ -558,7 +558,7 @@ trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr)
 static int trace_wakeup_test_thread(void *data)
 {
 	/* Make this a RT thread, doesn't need to be too high */
-	struct sched_param param = { .sched_priority = 5 };
+	static struct sched_param param = { .sched_priority = 5 };
 	struct completion *x = data;
 
 	sched_setscheduler(current, SCHED_FIFO, &param);

kernel/watchdog.c

@@ -307,7 +307,7 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
  */
 static int watchdog(void *unused)
 {
-	struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
+	static struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
 	struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer);
 
 	sched_setscheduler(current, SCHED_FIFO, &param);