8875125efe
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>
105 lines
2.2 KiB
C
105 lines
2.2 KiB
C
#include "sched.h"
|
|
|
|
/*
|
|
* idle-task scheduling class.
|
|
*
|
|
* (NOTE: these are not related to SCHED_IDLE tasks which are
|
|
* handled in sched/fair.c)
|
|
*/
|
|
|
|
#ifdef CONFIG_SMP
|
|
static int
|
|
select_task_rq_idle(struct task_struct *p, int cpu, int sd_flag, int flags)
|
|
{
|
|
return task_cpu(p); /* IDLE tasks as never migrated */
|
|
}
|
|
#endif /* CONFIG_SMP */
|
|
|
|
/*
|
|
* Idle tasks are unconditionally rescheduled:
|
|
*/
|
|
static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int flags)
|
|
{
|
|
resched_curr(rq);
|
|
}
|
|
|
|
static struct task_struct *
|
|
pick_next_task_idle(struct rq *rq, struct task_struct *prev)
|
|
{
|
|
put_prev_task(rq, prev);
|
|
|
|
schedstat_inc(rq, sched_goidle);
|
|
return rq->idle;
|
|
}
|
|
|
|
/*
|
|
* It is not legal to sleep in the idle task - print a warning
|
|
* message if some code attempts to do it:
|
|
*/
|
|
static void
|
|
dequeue_task_idle(struct rq *rq, struct task_struct *p, int flags)
|
|
{
|
|
raw_spin_unlock_irq(&rq->lock);
|
|
printk(KERN_ERR "bad: scheduling from the idle thread!\n");
|
|
dump_stack();
|
|
raw_spin_lock_irq(&rq->lock);
|
|
}
|
|
|
|
static void put_prev_task_idle(struct rq *rq, struct task_struct *prev)
|
|
{
|
|
idle_exit_fair(rq);
|
|
rq_last_tick_reset(rq);
|
|
}
|
|
|
|
static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued)
|
|
{
|
|
}
|
|
|
|
static void set_curr_task_idle(struct rq *rq)
|
|
{
|
|
}
|
|
|
|
static void switched_to_idle(struct rq *rq, struct task_struct *p)
|
|
{
|
|
BUG();
|
|
}
|
|
|
|
static void
|
|
prio_changed_idle(struct rq *rq, struct task_struct *p, int oldprio)
|
|
{
|
|
BUG();
|
|
}
|
|
|
|
static unsigned int get_rr_interval_idle(struct rq *rq, struct task_struct *task)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Simple, special scheduling class for the per-CPU idle tasks:
|
|
*/
|
|
const struct sched_class idle_sched_class = {
|
|
/* .next is NULL */
|
|
/* no enqueue/yield_task for idle tasks */
|
|
|
|
/* dequeue is not valid, we print a debug message there: */
|
|
.dequeue_task = dequeue_task_idle,
|
|
|
|
.check_preempt_curr = check_preempt_curr_idle,
|
|
|
|
.pick_next_task = pick_next_task_idle,
|
|
.put_prev_task = put_prev_task_idle,
|
|
|
|
#ifdef CONFIG_SMP
|
|
.select_task_rq = select_task_rq_idle,
|
|
#endif
|
|
|
|
.set_curr_task = set_curr_task_idle,
|
|
.task_tick = task_tick_idle,
|
|
|
|
.get_rr_interval = get_rr_interval_idle,
|
|
|
|
.prio_changed = prio_changed_idle,
|
|
.switched_to = switched_to_idle,
|
|
};
|