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/*
* Thread Queue Handler
*
*
* COPYRIGHT (c) 1989-1999.
* 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.com/license/LICENSE.
*
* $Id$
*/
#include <rtems/system.h>
#include <rtems/score/chain.h>
#include <rtems/score/isr.h>
#include <rtems/score/object.h>
#include <rtems/score/states.h>
#include <rtems/score/thread.h>
#include <rtems/score/threadq.h>
#include <rtems/score/tqdata.h>
/*PAGE
*
* _Thread_queue_Enqueue_priority
*
* This routine blocks a thread, places it on a thread, and optionally
* starts a timeout timer.
*
* Input parameters:
* the_thread_queue - pointer to threadq
* thread - thread to insert
* timeout - timeout interval in ticks
*
* Output parameters: NONE
*
* INTERRUPT LATENCY:
* forward less than
* forward equal
*/
void _Thread_queue_Enqueue_priority(
Thread_queue_Control *the_thread_queue,
Thread_Control *the_thread,
Watchdog_Interval timeout
)
{
Priority_Control search_priority;
Thread_Control *search_thread;
ISR_Level level;
Chain_Control *header;
unsigned32 header_index;
Chain_Node *the_node;
Chain_Node *next_node;
Chain_Node *previous_node;
Chain_Node *search_node;
Priority_Control priority;
States_Control block_state;
Thread_queue_States sync_state;
_Chain_Initialize_empty( &the_thread->Wait.Block2n );
priority = the_thread->current_priority;
header_index = _Thread_queue_Header_number( priority );
header = &the_thread_queue->Queues.Priority[ header_index ];
block_state = the_thread_queue->state;
if ( _Thread_queue_Is_reverse_search( priority ) )
goto restart_reverse_search;
restart_forward_search:
search_priority = PRIORITY_MINIMUM - 1;
_ISR_Disable( level );
search_thread = (Thread_Control *) header->first;
while ( !_Chain_Is_tail( header, (Chain_Node *)search_thread ) ) {
search_priority = search_thread->current_priority;
if ( priority <= search_priority )
break;
#if ( CPU_UNROLL_ENQUEUE_PRIORITY == TRUE )
search_thread = (Thread_Control *) search_thread->Object.Node.next;
if ( _Chain_Is_tail( header, (Chain_Node *)search_thread ) )
break;
search_priority = search_thread->current_priority;
if ( priority <= search_priority )
break;
#endif
_ISR_Flash( level );
if ( !_States_Are_set( search_thread->current_state, block_state) ) {
_ISR_Enable( level );
goto restart_forward_search;
}
search_thread =
(Thread_Control *)search_thread->Object.Node.next;
}
if ( the_thread_queue->sync_state != THREAD_QUEUE_NOTHING_HAPPENED )
goto synchronize;
the_thread_queue->sync_state = THREAD_QUEUE_SYNCHRONIZED;
if ( priority == search_priority )
goto equal_priority;
search_node = (Chain_Node *) search_thread;
previous_node = search_node->previous;
the_node = (Chain_Node *) the_thread;
the_node->next = search_node;
the_node->previous = previous_node;
previous_node->next = the_node;
search_node->previous = the_node;
_ISR_Enable( level );
return;
restart_reverse_search:
search_priority = PRIORITY_MAXIMUM + 1;
_ISR_Disable( level );
search_thread = (Thread_Control *) header->last;
while ( !_Chain_Is_head( header, (Chain_Node *)search_thread ) ) {
search_priority = search_thread->current_priority;
if ( priority >= search_priority )
break;
#if ( CPU_UNROLL_ENQUEUE_PRIORITY == TRUE )
search_thread = (Thread_Control *) search_thread->Object.Node.previous;
if ( _Chain_Is_head( header, (Chain_Node *)search_thread ) )
break;
search_priority = search_thread->current_priority;
if ( priority >= search_priority )
break;
#endif
_ISR_Flash( level );
if ( !_States_Are_set( search_thread->current_state, block_state) ) {
_ISR_Enable( level );
goto restart_reverse_search;
}
search_thread = (Thread_Control *)
search_thread->Object.Node.previous;
}
if ( the_thread_queue->sync_state != THREAD_QUEUE_NOTHING_HAPPENED )
goto synchronize;
the_thread_queue->sync_state = THREAD_QUEUE_SYNCHRONIZED;
if ( priority == search_priority )
goto equal_priority;
search_node = (Chain_Node *) search_thread;
next_node = search_node->next;
the_node = (Chain_Node *) the_thread;
the_node->next = next_node;
the_node->previous = search_node;
search_node->next = the_node;
next_node->previous = the_node;
_ISR_Enable( level );
return;
equal_priority: /* add at end of priority group */
search_node = _Chain_Tail( &search_thread->Wait.Block2n );
previous_node = search_node->previous;
the_node = (Chain_Node *) the_thread;
the_node->next = search_node;
the_node->previous = previous_node;
previous_node->next = the_node;
search_node->previous = the_node;
_ISR_Enable( level );
return;
synchronize:
sync_state = the_thread_queue->sync_state;
the_thread_queue->sync_state = THREAD_QUEUE_SYNCHRONIZED;
switch ( sync_state ) {
case THREAD_QUEUE_SYNCHRONIZED:
/*
* This should never happen. It indicates that someone did not
* enter a thread queue critical section.
*/
break;
case THREAD_QUEUE_NOTHING_HAPPENED:
/*
* This should never happen. All of this was dealt with above.
*/
break;
case THREAD_QUEUE_TIMEOUT:
the_thread->Wait.return_code = the_thread->Wait.queue->timeout_status;
_ISR_Enable( level );
break;
case THREAD_QUEUE_SATISFIED:
if ( _Watchdog_Is_active( &the_thread->Timer ) ) {
_Watchdog_Deactivate( &the_thread->Timer );
_ISR_Enable( level );
(void) _Watchdog_Remove( &the_thread->Timer );
} else
_ISR_Enable( level );
break;
}
/*
* Global objects with thread queue's should not be operated on from an
* ISR. But the sync code still must allow short timeouts to be processed
* correctly.
*/
_Thread_Unblock( the_thread );
#if defined(RTEMS_MULTIPROCESSING)
if ( !_Objects_Is_local_id( the_thread->Object.id ) )
_Thread_MP_Free_proxy( the_thread );
#endif
}
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