/**
* @file
*
* @brief Changes the Priority of a Thread
*
* @ingroup ScoreThread
*/
/*
* COPYRIGHT (c) 1989-2014.
* 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>
static Thread_Control *_Thread_Apply_priority_locked(
Thread_Control *the_thread,
Priority_Control new_priority,
void *arg,
Thread_Change_priority_filter filter,
bool prepend_it,
Thread_queue_Context *queue_context
)
{
/*
* For simplicity set the priority restore hint unconditionally since this is
* an average case optimization. Otherwise complicated atomic operations
* would be necessary. Synchronize with a potential read of the resource
* count in the filter function. See also _CORE_mutex_Surrender(),
* _Thread_Set_priority_filter() and _Thread_Restore_priority_filter().
*/
the_thread->priority_restore_hint = true;
_Atomic_Fence( ATOMIC_ORDER_ACQ_REL );
/*
* Do not bother recomputing all the priority related information if
* we are not REALLY changing priority.
*/
if ( ( *filter )( the_thread, &new_priority, arg ) ) {
_Scheduler_Thread_set_priority( the_thread, new_priority, prepend_it );
( *the_thread->Wait.operations->priority_change )(
the_thread->Wait.queue,
the_thread,
new_priority
);
} else {
the_thread = NULL;
}
return the_thread;
}
Thread_Control *_Thread_Apply_priority(
Thread_Control *the_thread,
Priority_Control new_priority,
void *arg,
Thread_Change_priority_filter filter,
bool prepend_it
)
{
Thread_queue_Context queue_context;
Thread_Control *the_thread_to_update;
_Thread_Wait_acquire( the_thread, &queue_context );
the_thread_to_update = _Thread_Apply_priority_locked(
the_thread,
new_priority,
arg,
filter,
prepend_it,
&queue_context
);
_Thread_Wait_release( the_thread, &queue_context );
return the_thread_to_update;
}
void _Thread_Update_priority( Thread_Control *the_thread )
{
if ( the_thread != NULL ) {
ISR_lock_Context lock_context;
_Thread_State_acquire( the_thread, &lock_context );
_Scheduler_Update_priority( the_thread );
_Thread_State_release( the_thread, &lock_context );
}
}
void _Thread_Change_priority(
Thread_Control *the_thread,
Priority_Control new_priority,
void *arg,
Thread_Change_priority_filter filter,
bool prepend_it
)
{
the_thread = _Thread_Apply_priority(
the_thread,
new_priority,
arg,
filter,
prepend_it
);
_Thread_Update_priority( the_thread );
}
static bool _Thread_Raise_priority_filter(
Thread_Control *the_thread,
Priority_Control *new_priority,
void *arg
)
{
return _Thread_Priority_less_than(
_Thread_Get_priority( the_thread ),
*new_priority
);
}
void _Thread_Raise_priority(
Thread_Control *the_thread,
Priority_Control new_priority
)
{
_Thread_Change_priority(
the_thread,
new_priority,
NULL,
_Thread_Raise_priority_filter,
false
);
}
static bool _Thread_Restore_priority_filter(
Thread_Control *the_thread,
Priority_Control *new_priority,
void *arg
)
{
*new_priority = the_thread->real_priority;
the_thread->priority_restore_hint = false;
return *new_priority != _Thread_Get_priority( the_thread );
}
void _Thread_Restore_priority( Thread_Control *the_thread )
{
_Thread_Change_priority(
the_thread,
0,
NULL,
_Thread_Restore_priority_filter,
true
);
}