^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * stop-task scheduling class.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * The stop task is the highest priority task in the system, it preempts
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * everything and will be preempted by nothing.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * See kernel/stop_machine.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include "sched.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #ifdef CONFIG_SMP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) static int
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) select_task_rq_stop(struct task_struct *p, int cpu, int sd_flag, int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) return task_cpu(p); /* stop tasks as never migrate */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) static int
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) balance_stop(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) return sched_stop_runnable(rq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) #endif /* CONFIG_SMP */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) static void
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) check_preempt_curr_stop(struct rq *rq, struct task_struct *p, int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) /* we're never preempted */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) static void set_next_task_stop(struct rq *rq, struct task_struct *stop, bool first)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) stop->se.exec_start = rq_clock_task(rq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) static struct task_struct *pick_next_task_stop(struct rq *rq)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) if (!sched_stop_runnable(rq))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) set_next_task_stop(rq, rq->stop, true);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) return rq->stop;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) static void
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) enqueue_task_stop(struct rq *rq, struct task_struct *p, int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) add_nr_running(rq, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) static void
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) dequeue_task_stop(struct rq *rq, struct task_struct *p, int flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) sub_nr_running(rq, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) static void yield_task_stop(struct rq *rq)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) BUG(); /* the stop task should never yield, its pointless. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) static void put_prev_task_stop(struct rq *rq, struct task_struct *prev)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) struct task_struct *curr = rq->curr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) u64 delta_exec;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) delta_exec = rq_clock_task(rq) - curr->se.exec_start;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) if (unlikely((s64)delta_exec < 0))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) delta_exec = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) schedstat_set(curr->se.statistics.exec_max,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) max(curr->se.statistics.exec_max, delta_exec));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) curr->se.sum_exec_runtime += delta_exec;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) account_group_exec_runtime(curr, delta_exec);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) curr->se.exec_start = rq_clock_task(rq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) cgroup_account_cputime(curr, delta_exec);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) * scheduler tick hitting a task of our scheduling class.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) * NOTE: This function can be called remotely by the tick offload that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) * goes along full dynticks. Therefore no local assumption can be made
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) * and everything must be accessed through the @rq and @curr passed in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) * parameters.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) static void task_tick_stop(struct rq *rq, struct task_struct *curr, int queued)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) static void switched_to_stop(struct rq *rq, struct task_struct *p)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) BUG(); /* its impossible to change to this class */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) static void
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) prio_changed_stop(struct rq *rq, struct task_struct *p, int oldprio)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) BUG(); /* how!?, what priority? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) static void update_curr_stop(struct rq *rq)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) * Simple, special scheduling class for the per-CPU stop tasks:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) const struct sched_class stop_sched_class
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) __section("__stop_sched_class") = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) .enqueue_task = enqueue_task_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) .dequeue_task = dequeue_task_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) .yield_task = yield_task_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) .check_preempt_curr = check_preempt_curr_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) .pick_next_task = pick_next_task_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) .put_prev_task = put_prev_task_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) .set_next_task = set_next_task_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) #ifdef CONFIG_SMP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) .balance = balance_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) .select_task_rq = select_task_rq_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) .set_cpus_allowed = set_cpus_allowed_common,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) .task_tick = task_tick_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) .prio_changed = prio_changed_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) .switched_to = switched_to_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) .update_curr = update_curr_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) };
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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