1 // SPDX-License-Identifier: GPL-2.0
5 * idle-task scheduling class.
7 * (NOTE: these are not related to SCHED_IDLE tasks which are
8 * handled in sched/fair.c)
13 select_task_rq_idle(struct task_struct
*p
, int cpu
, int sd_flag
, int flags
)
15 return task_cpu(p
); /* IDLE tasks as never migrated */
17 #endif /* CONFIG_SMP */
20 * Idle tasks are unconditionally rescheduled:
22 static void check_preempt_curr_idle(struct rq
*rq
, struct task_struct
*p
, int flags
)
27 static struct task_struct
*
28 pick_next_task_idle(struct rq
*rq
, struct task_struct
*prev
, struct rq_flags
*rf
)
30 put_prev_task(rq
, prev
);
32 schedstat_inc(rq
->sched_goidle
);
37 * It is not legal to sleep in the idle task - print a warning
38 * message if some code attempts to do it:
41 dequeue_task_idle(struct rq
*rq
, struct task_struct
*p
, int flags
)
43 raw_spin_unlock_irq(&rq
->lock
);
44 printk(KERN_ERR
"bad: scheduling from the idle thread!\n");
46 raw_spin_lock_irq(&rq
->lock
);
49 static void put_prev_task_idle(struct rq
*rq
, struct task_struct
*prev
)
51 rq_last_tick_reset(rq
);
54 static void task_tick_idle(struct rq
*rq
, struct task_struct
*curr
, int queued
)
58 static void set_curr_task_idle(struct rq
*rq
)
62 static void switched_to_idle(struct rq
*rq
, struct task_struct
*p
)
68 prio_changed_idle(struct rq
*rq
, struct task_struct
*p
, int oldprio
)
73 static unsigned int get_rr_interval_idle(struct rq
*rq
, struct task_struct
*task
)
78 static void update_curr_idle(struct rq
*rq
)
83 * Simple, special scheduling class for the per-CPU idle tasks:
85 const struct sched_class idle_sched_class
= {
87 /* no enqueue/yield_task for idle tasks */
89 /* dequeue is not valid, we print a debug message there: */
90 .dequeue_task
= dequeue_task_idle
,
92 .check_preempt_curr
= check_preempt_curr_idle
,
94 .pick_next_task
= pick_next_task_idle
,
95 .put_prev_task
= put_prev_task_idle
,
98 .select_task_rq
= select_task_rq_idle
,
99 .set_cpus_allowed
= set_cpus_allowed_common
,
102 .set_curr_task
= set_curr_task_idle
,
103 .task_tick
= task_tick_idle
,
105 .get_rr_interval
= get_rr_interval_idle
,
107 .prio_changed
= prio_changed_idle
,
108 .switched_to
= switched_to_idle
,
109 .update_curr
= update_curr_idle
,