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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120// SPDX-License-Identifier: GPL-2.0/* * stop-task scheduling class. * * The stop task is the highest priority task in the system, it preempts * everything and will be preempted by nothing. * * See kernel/stop_machine.c */#include "sched.h"
static intselect_task_rq_stop(struct task_struct *p, int cpu, int flags){ return task_cpu(p); /* stop tasks as never migrate */}
static intbalance_stop(struct rq *rq, struct rq_flags *rf){ return sched_stop_runnable(rq);}
static voidwakeup_preempt_stop(struct rq *rq, struct task_struct *p, int flags){ /* we're never preempted */}
static void set_next_task_stop(struct rq *rq, struct task_struct *stop, bool first){ stop->se.exec_start = rq_clock_task(rq);}
static struct task_struct *pick_task_stop(struct rq *rq, struct rq_flags *rf){ if (!sched_stop_runnable(rq)) return NULL;
return rq->stop;}
static voidenqueue_task_stop(struct rq *rq, struct task_struct *p, int flags){ add_nr_running(rq, 1);}
static booldequeue_task_stop(struct rq *rq, struct task_struct *p, int flags){ sub_nr_running(rq, 1); return true;}
static void yield_task_stop(struct rq *rq){ BUG(); /* the stop task should never yield, its pointless. */}
static void put_prev_task_stop(struct rq *rq, struct task_struct *prev, struct task_struct *next){ update_curr_common(rq);}
/* * 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_stop(struct rq *rq, struct task_struct *curr, int queued){}
static void switching_to_stop(struct rq *rq, struct task_struct *p){ BUG(); /* its impossible to change to this class */}
static voidprio_changed_stop(struct rq *rq, struct task_struct *p, u64 oldprio){ if (p->prio == oldprio) return;
BUG(); /* how!?, what priority? */}
static void update_curr_stop(struct rq *rq){}
/* * Simple, special scheduling class for the per-CPU stop tasks: */DEFINE_SCHED_CLASS(stop) = { .enqueue_task = enqueue_task_stop, .dequeue_task = dequeue_task_stop, .yield_task = yield_task_stop,
.wakeup_preempt = wakeup_preempt_stop,
.pick_task = pick_task_stop, .put_prev_task = put_prev_task_stop, .set_next_task = set_next_task_stop,
.balance = balance_stop, .select_task_rq = select_task_rq_stop, .set_cpus_allowed = set_cpus_allowed_common,
.task_tick = task_tick_stop,
.prio_changed = prio_changed_stop, .switching_to = switching_to_stop, .update_curr = update_curr_stop,};