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/**
* @file
*
* @brief Unblocks a Thread from the Queue
*
* @ingroup ScoreScheduler
*/
/*
* Copyright (C) 2011 Petr Benes.
* Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/score/schedulercbs.h>
#include <rtems/score/schedulerimpl.h>
#include <rtems/score/threadimpl.h>
#include <rtems/score/watchdogimpl.h>
void _Scheduler_CBS_Unblock(
Scheduler_Control *scheduler,
Thread_Control *the_thread
)
{
Scheduler_CBS_Per_thread *sched_info;
Scheduler_CBS_Server *serv_info;
Priority_Control new_priority;
_Scheduler_EDF_Enqueue( scheduler, the_thread );
/* TODO: flash critical section? */
sched_info = (Scheduler_CBS_Per_thread *) the_thread->scheduler_info;
serv_info = (Scheduler_CBS_Server *) sched_info->cbs_server;
/*
* Late unblock rule for deadline-driven tasks. The remaining time to
* deadline must be sufficient to serve the remaining computation time
* without increased utilization of this task. It might cause a deadline
* miss of another task.
*/
if (serv_info) {
time_t deadline = serv_info->parameters.deadline;
time_t budget = serv_info->parameters.budget;
time_t deadline_left = the_thread->cpu_time_budget;
time_t budget_left = the_thread->real_priority -
_Watchdog_Ticks_since_boot;
if ( deadline*budget_left > budget*deadline_left ) {
/* Put late unblocked task to background until the end of period. */
new_priority = the_thread->Start.initial_priority;
if ( the_thread->real_priority != new_priority )
the_thread->real_priority = new_priority;
if ( the_thread->current_priority != new_priority )
_Thread_Change_priority(the_thread, new_priority, true);
}
}
/*
* If the thread that was unblocked is more important than the heir,
* then we have a new heir. This may or may not result in a
* context switch.
*
* Normal case:
* If the current thread is preemptible, then we need to do
* a context switch.
* Pseudo-ISR case:
* Even if the thread isn't preemptible, if the new heir is
* a pseudo-ISR system task, we need to do a context switch.
*/
if (
_Scheduler_Is_priority_higher_than(
scheduler,
the_thread->current_priority,
_Thread_Heir->current_priority
)
) {
_Thread_Heir = the_thread;
if ( _Thread_Executing->is_preemptible ||
the_thread->current_priority == 0 )
_Thread_Dispatch_necessary = true;
}
}
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