score/src/schedulercbsunblock.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup RTEMSScoreSchedulerCBS
0007  *
0008  * @brief This source file contains the implementation of
0009  *   _Scheduler_CBS_Unblock().
0010  */
0011
0012 /*
0013  *  Copyright (C) 2011 Petr Benes.
0014  *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
0015  *
0016  * Redistribution and use in source and binary forms, with or without
0017  * modification, are permitted provided that the following conditions
0018  * are met:
0019  * 1. Redistributions of source code must retain the above copyright
0020  *    notice, this list of conditions and the following disclaimer.
0021  * 2. Redistributions in binary form must reproduce the above copyright
0022  *    notice, this list of conditions and the following disclaimer in the
0023  *    documentation and/or other materials provided with the distribution.
0024  *
0025  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0026  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0027  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0028  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0029  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0030  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0031  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0032  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0033  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0034  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0035  * POSSIBILITY OF SUCH DAMAGE.
0036  */
0037
0038 #ifdef HAVE_CONFIG_H
0039 #include "config.h"
0040 #endif
0041
0042 #include <rtems/score/schedulercbsimpl.h>
0043 #include <rtems/score/scheduleredfimpl.h>
0044 #include <rtems/score/schedulerimpl.h>
0045 #include <rtems/score/threadimpl.h>
0046 #include <rtems/score/watchdogimpl.h>
0047
0048 void _Scheduler_CBS_Unblock(
0049   const Scheduler_Control *scheduler,
0050   Thread_Control          *the_thread,
0051   Scheduler_Node          *node
0052 )
0053 {
0054   Scheduler_CBS_Node   *the_node;
0055   Scheduler_CBS_Server *serv_info;
0056   Priority_Control      priority;
0057
0058   the_node = _Scheduler_CBS_Node_downcast( node );
0059   serv_info = the_node->cbs_server;
0060   priority = _Scheduler_Node_get_priority( &the_node->Base.Base );
0061   priority = SCHEDULER_PRIORITY_PURIFY( priority );
0062
0063   /*
0064    * Late unblock rule for deadline-driven tasks. The remaining time to
0065    * deadline must be sufficient to serve the remaining computation time
0066    * without increased utilization of this task. It might cause a deadline
0067    * miss of another task.
0068    */
0069   if ( serv_info != NULL && ( priority & SCHEDULER_EDF_PRIO_MSB ) == 0 ) {
0070     time_t deadline = serv_info->parameters.deadline;
0071     time_t budget = serv_info->parameters.budget;
0072     uint32_t deadline_left = the_thread->CPU_budget.available;
0073     Priority_Control budget_left = priority - _Watchdog_Ticks_since_boot;
0074
0075     if ( deadline * budget_left > budget * deadline_left ) {
0076       Thread_queue_Context queue_context;
0077
0078       /* Put late unblocked task to background until the end of period. */
0079       _Thread_queue_Context_clear_priority_updates( &queue_context );
0080       _Scheduler_CBS_Cancel_job(
0081         scheduler,
0082         the_thread,
0083         the_node->deadline_node,
0084         &queue_context
0085       );
0086     }
0087   }
0088
0089   _Scheduler_EDF_Unblock( scheduler, the_thread, &the_node->Base.Base );
0090 }