1 | /** |
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2 | * @file rtems/score/scheduleredf.h |
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3 | * |
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4 | * @brief Data Related to the Manipulation of Threads for the EDF Scheduler |
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5 | * |
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6 | * This include file contains all the constants and structures associated |
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7 | * with the manipulation of threads for the EDF scheduler. |
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8 | */ |
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9 | |
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10 | /* |
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11 | * Copryight (c) 2011 Petr Benes. |
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12 | * Copyright (C) 2011 On-Line Applications Research Corporation (OAR). |
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13 | * |
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14 | * The license and distribution terms for this file may be |
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15 | * found in the file LICENSE in this distribution or at |
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16 | * http://www.rtems.org/license/LICENSE. |
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17 | */ |
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18 | |
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19 | #ifndef _RTEMS_SCORE_SCHEDULEREDF_H |
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20 | #define _RTEMS_SCORE_SCHEDULEREDF_H |
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21 | |
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22 | #include <rtems/score/priority.h> |
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23 | #include <rtems/score/scheduler.h> |
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24 | #include <rtems/score/schedulerpriority.h> |
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25 | #include <rtems/score/rbtree.h> |
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26 | |
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27 | #ifdef __cplusplus |
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28 | extern "C" { |
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29 | #endif |
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30 | |
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31 | /** |
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32 | * @defgroup ScoreSchedulerEDF EDF Scheduler |
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33 | * |
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34 | * @ingroup ScoreScheduler |
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35 | */ |
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36 | /**@{*/ |
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37 | |
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38 | #define SCHEDULER_EDF_MAXIMUM_PRIORITY 0x7fffffff |
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39 | |
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40 | /** |
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41 | * Entry points for the Earliest Deadline First Scheduler. |
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42 | */ |
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43 | #define SCHEDULER_EDF_ENTRY_POINTS \ |
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44 | { \ |
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45 | _Scheduler_EDF_Initialize, /* initialize entry point */ \ |
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46 | _Scheduler_EDF_Schedule, /* schedule entry point */ \ |
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47 | _Scheduler_EDF_Yield, /* yield entry point */ \ |
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48 | _Scheduler_EDF_Block, /* block entry point */ \ |
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49 | _Scheduler_EDF_Unblock, /* unblock entry point */ \ |
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50 | _Scheduler_EDF_Update_priority, /* update priority entry point */ \ |
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51 | _Scheduler_EDF_Map_priority, /* map priority entry point */ \ |
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52 | _Scheduler_EDF_Unmap_priority, /* unmap priority entry point */ \ |
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53 | SCHEDULER_OPERATION_DEFAULT_ASK_FOR_HELP \ |
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54 | _Scheduler_EDF_Node_initialize, /* node initialize entry point */ \ |
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55 | _Scheduler_default_Node_destroy, /* node destroy entry point */ \ |
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56 | _Scheduler_EDF_Release_job, /* new period of task */ \ |
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57 | _Scheduler_default_Tick, /* tick entry point */ \ |
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58 | _Scheduler_default_Start_idle /* start idle entry point */ \ |
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59 | SCHEDULER_OPERATION_DEFAULT_GET_SET_AFFINITY \ |
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60 | } |
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61 | |
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62 | /** |
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63 | * This is just a most significant bit of Priority_Control type. It |
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64 | * distinguishes threads which are deadline driven (priority |
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65 | * represented by a lower number than @a SCHEDULER_EDF_PRIO_MSB) from those |
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66 | * ones who do not have any deadlines and thus are considered background |
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67 | * tasks. |
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68 | */ |
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69 | #define SCHEDULER_EDF_PRIO_MSB 0x80000000 |
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70 | |
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71 | typedef struct { |
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72 | /** |
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73 | * @brief Basic scheduler context. |
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74 | */ |
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75 | Scheduler_Context Base; |
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76 | |
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77 | /** |
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78 | * Top of the ready queue. |
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79 | */ |
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80 | RBTree_Control Ready; |
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81 | } Scheduler_EDF_Context; |
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82 | |
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83 | /** |
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84 | * @brief Scheduler node specialization for EDF schedulers. |
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85 | */ |
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86 | typedef struct { |
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87 | /** |
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88 | * @brief Basic scheduler node. |
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89 | */ |
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90 | Scheduler_Node Base; |
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91 | |
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92 | /** |
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93 | * Pointer to corresponding Thread Control Block. |
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94 | */ |
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95 | Thread_Control *thread; |
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96 | /** |
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97 | * Rbtree node related to this thread. |
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98 | */ |
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99 | RBTree_Node Node; |
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100 | |
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101 | /** |
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102 | * @brief The thread priority used by this scheduler instance in case no job |
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103 | * is released. |
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104 | */ |
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105 | Priority_Control background_priority; |
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106 | |
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107 | /** |
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108 | * @brief The thread priority currently used by this scheduler instance. |
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109 | */ |
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110 | Priority_Control current_priority; |
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111 | } Scheduler_EDF_Node; |
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112 | |
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113 | /** |
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114 | * @brief Initialize EDF scheduler. |
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115 | * |
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116 | * This routine initializes the EDF scheduler. |
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117 | * |
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118 | * @param[in] scheduler The scheduler instance. |
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119 | */ |
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120 | void _Scheduler_EDF_Initialize( const Scheduler_Control *scheduler ); |
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121 | |
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122 | /** |
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123 | * @brief Removes thread from ready queue. |
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124 | * |
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125 | * This routine removes @a the_thread from the scheduling decision, |
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126 | * that is, removes it from the ready queue. It performs |
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127 | * any necessary scheduling operations including the selection of |
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128 | * a new heir thread. |
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129 | * |
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130 | * @param[in] scheduler The scheduler instance. |
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131 | * @param[in] the_thread is the thread to be blocked. |
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132 | */ |
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133 | void _Scheduler_EDF_Block( |
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134 | const Scheduler_Control *scheduler, |
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135 | Thread_Control *the_thread |
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136 | ); |
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137 | |
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138 | /** |
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139 | * @brief Sets the heir thread to be the next ready thread |
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140 | * in the rbtree ready queue. |
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141 | * |
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142 | * This kernel routine sets the heir thread to be the next ready thread |
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143 | * in the rbtree ready queue. |
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144 | * |
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145 | * @param[in] scheduler The scheduler instance. |
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146 | * @param[in] the_thread being scheduled. |
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147 | */ |
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148 | void _Scheduler_EDF_Schedule( |
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149 | const Scheduler_Control *scheduler, |
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150 | Thread_Control *the_thread |
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151 | ); |
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152 | |
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153 | /** |
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154 | * @brief Initializes an EDF specific scheduler node of @a the_thread. |
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155 | * |
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156 | * @param[in] scheduler The scheduler instance. |
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157 | * @param[in] the_thread being initialized. |
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158 | * @param[in] priority The thread priority. |
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159 | */ |
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160 | void _Scheduler_EDF_Node_initialize( |
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161 | const Scheduler_Control *scheduler, |
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162 | Thread_Control *the_thread, |
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163 | Priority_Control priority |
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164 | ); |
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165 | |
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166 | /** |
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167 | * @brief Adds @a the_thread to the scheduling decision. |
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168 | * |
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169 | * This routine adds @a the_thread to the scheduling decision, that is, |
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170 | * adds it to the ready queue and updates any appropriate scheduling |
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171 | * variables, for example the heir thread. |
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172 | * |
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173 | * @param[in] scheduler The scheduler instance. |
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174 | * @param[in] the_thread will be unblocked. |
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175 | */ |
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176 | Scheduler_Void_or_thread _Scheduler_EDF_Unblock( |
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177 | const Scheduler_Control *scheduler, |
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178 | Thread_Control *the_thread |
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179 | ); |
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180 | |
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181 | Scheduler_Void_or_thread _Scheduler_EDF_Update_priority( |
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182 | const Scheduler_Control *scheduler, |
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183 | Thread_Control *the_thread |
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184 | ); |
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185 | |
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186 | Priority_Control _Scheduler_EDF_Map_priority( |
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187 | const Scheduler_Control *scheduler, |
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188 | Priority_Control priority |
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189 | ); |
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190 | |
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191 | Priority_Control _Scheduler_EDF_Unmap_priority( |
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192 | const Scheduler_Control *scheduler, |
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193 | Priority_Control priority |
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194 | ); |
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195 | |
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196 | /** |
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197 | * @brief invoked when a thread wishes to voluntarily |
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198 | * transfer control of the processor to another thread |
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199 | * with equal deadline. |
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200 | * |
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201 | * This routine is invoked when a thread wishes to voluntarily |
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202 | * transfer control of the processor to another thread in the queue with |
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203 | * equal deadline. This does not have to happen very often. |
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204 | * |
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205 | * This routine will remove the specified THREAD from the ready queue |
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206 | * and place it back. The rbtree ready queue is responsible for FIFO ordering |
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207 | * in such a case. |
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208 | * |
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209 | * @param[in] scheduler The scheduler instance. |
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210 | * @param[in,out] the_thread The yielding thread. |
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211 | */ |
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212 | Scheduler_Void_or_thread _Scheduler_EDF_Yield( |
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213 | const Scheduler_Control *scheduler, |
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214 | Thread_Control *the_thread |
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215 | ); |
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216 | |
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217 | /** |
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218 | * @brief Called when a new job of task is released. |
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219 | * |
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220 | * This routine is called when a new job of task is released. |
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221 | * It is called only from Rate Monotonic manager in the beginning |
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222 | * of new period. |
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223 | * |
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224 | * @param[in] scheduler The scheduler instance. |
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225 | * @param[in] the_thread is the owner of the job. |
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226 | * @param[in] deadline of the new job from now. If equal to 0, |
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227 | * the job was cancelled or deleted, thus a running task |
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228 | * has to be suspended. |
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229 | */ |
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230 | void _Scheduler_EDF_Release_job ( |
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231 | const Scheduler_Control *scheduler, |
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232 | Thread_Control *the_thread, |
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233 | uint64_t deadline |
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234 | ); |
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235 | |
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236 | #ifdef __cplusplus |
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237 | } |
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238 | #endif |
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239 | |
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240 | /**@}*/ |
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241 | |
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242 | #endif |
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243 | /* end of include file */ |
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