score/src/threadscheduler.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup RTEMSScoreThread
0007  *
0008  * @brief This source file contains the implementation of
0009  *   _Thread_Scheduler_process_requests().
0010  */
0011
0012 /*
0013  * Copyright (c) 2016 embedded brains GmbH & Co. KG
0014  *
0015  * Redistribution and use in source and binary forms, with or without
0016  * modification, are permitted provided that the following conditions
0017  * are met:
0018  * 1. Redistributions of source code must retain the above copyright
0019  *    notice, this list of conditions and the following disclaimer.
0020  * 2. Redistributions in binary form must reproduce the above copyright
0021  *    notice, this list of conditions and the following disclaimer in the
0022  *    documentation and/or other materials provided with the distribution.
0023  *
0024  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0025  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0026  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0027  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0028  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0029  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0030  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0031  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0032  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0033  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0034  * POSSIBILITY OF SUCH DAMAGE.
0035  */
0036
0037 #ifdef HAVE_CONFIG_H
0038 #include "config.h"
0039 #endif
0040
0041 #include <rtems/score/threadimpl.h>
0042 #include <rtems/score/schedulerimpl.h>
0043
0044 #if defined(RTEMS_SMP)
0045 static void _Thread_Scheduler_withdraw_nodes(
0046   Thread_Control *the_thread,
0047   Scheduler_Node *scheduler_node
0048 )
0049 {
0050   while ( scheduler_node != NULL ) {
0051     Scheduler_Node          *next;
0052     const Scheduler_Control *scheduler;
0053     ISR_lock_Context         lock_context;
0054
0055     next = scheduler_node->Thread.Scheduler_node.next;
0056 #if defined(RTEMS_DEBUG)
0057     scheduler_node->Thread.Scheduler_node.next = NULL;
0058 #endif
0059
0060     scheduler = _Scheduler_Node_get_scheduler( scheduler_node );
0061
0062     _Scheduler_Acquire_critical( scheduler, &lock_context );
0063     ( *scheduler->Operations.withdraw_node )(
0064       scheduler,
0065       the_thread,
0066       scheduler_node,
0067       THREAD_SCHEDULER_READY
0068     );
0069     _Scheduler_Release_critical( scheduler, &lock_context );
0070
0071     scheduler_node = next;
0072   }
0073 }
0074
0075 void _Thread_Scheduler_process_requests( Thread_Control *the_thread )
0076 {
0077   ISR_lock_Context  lock_context;
0078   Scheduler_Node   *scheduler_node;
0079
0080   _Thread_Scheduler_acquire_critical( the_thread, &lock_context );
0081
0082   scheduler_node = the_thread->Scheduler.requests;
0083
0084   if ( scheduler_node != NULL ) {
0085     Scheduler_Node *remove;
0086
0087     the_thread->Scheduler.requests = NULL;
0088     remove = NULL;
0089
0090     do {
0091       Scheduler_Node_request request;
0092       Scheduler_Node        *next;
0093
0094       request = scheduler_node->Thread.request;
0095       scheduler_node->Thread.request = SCHEDULER_NODE_REQUEST_NOT_PENDING;
0096
0097       next = scheduler_node->Thread.next_request;
0098 #if defined(RTEMS_DEBUG)
0099       scheduler_node->Thread.next_request = NULL;
0100 #endif
0101
0102       if ( request == SCHEDULER_NODE_REQUEST_ADD ) {
0103         ++the_thread->Scheduler.helping_nodes;
0104         _Chain_Append_unprotected(
0105           &the_thread->Scheduler.Scheduler_nodes,
0106           &scheduler_node->Thread.Scheduler_node.Chain
0107         );
0108       } else if ( request == SCHEDULER_NODE_REQUEST_REMOVE ) {
0109         --the_thread->Scheduler.helping_nodes;
0110         _Chain_Extract_unprotected(
0111           &scheduler_node->Thread.Scheduler_node.Chain
0112         );
0113         scheduler_node->Thread.Scheduler_node.next = remove;
0114         remove = scheduler_node;
0115       } else {
0116         _Assert( request == SCHEDULER_NODE_REQUEST_NOTHING );
0117       }
0118
0119       scheduler_node = next;
0120     } while ( scheduler_node != NULL );
0121
0122     _Thread_Scheduler_release_critical( the_thread, &lock_context );
0123     _Thread_Scheduler_withdraw_nodes( the_thread, remove );
0124   } else {
0125     _Thread_Scheduler_release_critical( the_thread, &lock_context );
0126   }
0127 }
0128 #endif