64 lines
1.7 KiB
C
64 lines
1.7 KiB
C
/*
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* Copyright (C) 2018-2022 Intel Corporation.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <asm/cpu.h>
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#include <schedule.h>
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#include <event.h>
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#include <logmsg.h>
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void init_event(struct sched_event *event)
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{
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spinlock_init(&event->lock);
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event->set = false;
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event->waiting_thread = NULL;
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}
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void reset_event(struct sched_event *event)
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{
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uint64_t rflag;
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spinlock_irqsave_obtain(&event->lock, &rflag);
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event->set = false;
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event->waiting_thread = NULL;
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spinlock_irqrestore_release(&event->lock, rflag);
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}
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/* support exclusive waiting only
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*
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* During wait, the pCPU could be scheduled to run the idle thread when run queue
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* is empty. Signal_event() can happen when schedule() is in process.
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* This signal_event is not going to be lost, for the idle thread will always
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* check need_reschedule() after it is switched to at schedule().
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*/
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void wait_event(struct sched_event *event)
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{
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uint64_t rflag;
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spinlock_irqsave_obtain(&event->lock, &rflag);
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ASSERT((event->waiting_thread == NULL), "only support exclusive waiting");
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event->waiting_thread = sched_get_current(get_pcpu_id());
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while (!event->set && (event->waiting_thread != NULL)) {
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sleep_thread(event->waiting_thread);
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spinlock_irqrestore_release(&event->lock, rflag);
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schedule();
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spinlock_irqsave_obtain(&event->lock, &rflag);
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}
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event->set = false;
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event->waiting_thread = NULL;
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spinlock_irqrestore_release(&event->lock, rflag);
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}
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void signal_event(struct sched_event *event)
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{
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uint64_t rflag;
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spinlock_irqsave_obtain(&event->lock, &rflag);
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event->set = true;
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if (event->waiting_thread != NULL) {
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wake_thread(event->waiting_thread);
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}
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spinlock_irqrestore_release(&event->lock, rflag);
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}
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