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/**
* @file
*
* @brief Changes the Priority of a Thread
*
* @ingroup ScoreThread
*/
/*
* COPYRIGHT (c) 1989-2011.
* 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/threadimpl.h>
#include <rtems/score/schedulerimpl.h>
#include <rtems/score/threadqimpl.h>
/**
* @brief Invoked when a thread changes priority and is blocked.
*
* This routine is invoked when a thread changes priority and is
* blocked on a thread queue. If the queue is priority ordered,
* the_thread is removed from the_thread_queue and reinserted using
* its new priority. This method has no impact on the state of the_thread
* or of any timeouts associated with this blocking.
*
* @param[in] the_thread_queue pointer to a threadq header
* @param[in] the_thread pointer to a thread control block
*/
static void _Thread_queue_Requeue(
Thread_queue_Control *the_thread_queue,
Thread_Control *the_thread
)
{
/*
* Just in case the thread really wasn't blocked on a thread queue
* when we get here.
*/
if ( !the_thread_queue )
return;
/*
* If queueing by FIFO, there is nothing to do. This only applies to
* priority blocking discipline.
*/
if ( the_thread_queue->discipline == THREAD_QUEUE_DISCIPLINE_PRIORITY ) {
Thread_queue_Control *tq = the_thread_queue;
ISR_Level level;
ISR_Level level_ignored;
_ISR_Disable( level );
if ( _States_Is_waiting_on_thread_queue( the_thread->current_state ) ) {
_Thread_queue_Enter_critical_section( tq );
_Thread_queue_Extract_priority_helper(
the_thread,
the_thread->Wait.return_code,
true
);
(void) _Thread_queue_Enqueue_priority( tq, the_thread, &level_ignored );
}
_ISR_Enable( level );
}
}
void _Thread_Change_priority(
Thread_Control *the_thread,
Priority_Control new_priority,
bool prepend_it
)
{
/*
* Do not bother recomputing all the priority related information if
* we are not REALLY changing priority.
*/
if ( the_thread->current_priority != new_priority ) {
ISR_Level level;
_ISR_Disable( level );
the_thread->current_priority = new_priority;
if ( _States_Is_ready( the_thread->current_state ) ) {
_Scheduler_Change_priority(
the_thread,
new_priority,
prepend_it
);
_ISR_Flash( level );
/*
* We altered the set of thread priorities. So let's figure out
* who is the heir and if we need to switch to them.
*/
_Scheduler_Schedule( the_thread );
} else {
_Scheduler_Update_priority( the_thread, new_priority );
}
_ISR_Enable( level );
_Thread_queue_Requeue( the_thread->Wait.queue, the_thread );
}
}
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