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author | Ingo Molnar <mingo@kernel.org> | 2018-03-03 15:44:39 +0100 |
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committer | Ingo Molnar <mingo@kernel.org> | 2018-03-04 12:39:33 +0100 |
commit | a92057e14beb233e8c891f4de075f2a468c71f15 (patch) | |
tree | 44b4519c69a3bffba7a8f31437fe356b48783e3e /kernel/sched/idle.c | |
parent | sched/headers: Simplify and clean up header usage in the scheduler (diff) | |
download | linux-a92057e14beb233e8c891f4de075f2a468c71f15.tar.xz linux-a92057e14beb233e8c891f4de075f2a468c71f15.zip |
sched/idle: Merge kernel/sched/idle.c and kernel/sched/idle_task.c
Merge these two small .c modules as they implement two aspects
of idle task handling.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/idle.c')
-rw-r--r-- | kernel/sched/idle.c | 123 |
1 files changed, 122 insertions, 1 deletions
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 2760e0357271..2975f195e1c4 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -1,5 +1,9 @@ /* - * Generic entry points for the idle threads + * Generic entry points for the idle threads and + * implementation of the idle task scheduling class. + * + * (NOTE: these are not related to SCHED_IDLE batch scheduled + * tasks which are handled in sched/fair.c ) */ #include "sched.h" @@ -33,6 +37,7 @@ void cpu_idle_poll_ctrl(bool enable) static int __init cpu_idle_poll_setup(char *__unused) { cpu_idle_force_poll = 1; + return 1; } __setup("nohlt", cpu_idle_poll_setup); @@ -40,6 +45,7 @@ __setup("nohlt", cpu_idle_poll_setup); static int __init cpu_idle_nopoll_setup(char *__unused) { cpu_idle_force_poll = 0; + return 1; } __setup("hlt", cpu_idle_nopoll_setup); @@ -51,12 +57,14 @@ static noinline int __cpuidle cpu_idle_poll(void) trace_cpu_idle_rcuidle(0, smp_processor_id()); local_irq_enable(); stop_critical_timings(); + while (!tif_need_resched() && (cpu_idle_force_poll || tick_check_broadcast_expired())) cpu_relax(); start_critical_timings(); trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); rcu_idle_exit(); + return 1; } @@ -337,3 +345,116 @@ void cpu_startup_entry(enum cpuhp_state state) while (1) do_idle(); } + +/* + * idle-task scheduling class. + */ + +#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 + +/* + * 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, struct rq_flags *rf) +{ + put_prev_task(rq, prev); + update_idle_core(rq); + 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) +{ +} + +/* + * scheduler tick hitting a task of our scheduling class. + * + * NOTE: This function can be called remotely by the tick offload that + * goes along full dynticks. Therefore no local assumption can be made + * and everything must be accessed through the @rq and @curr passed in + * parameters. + */ +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; +} + +static void update_curr_idle(struct rq *rq) +{ +} + +/* + * 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, + .set_cpus_allowed = set_cpus_allowed_common, +#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, + .update_curr = update_curr_idle, +}; |