1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief Rate Monotonic Support |
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5 | * @ingroup ClassicRateMon |
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6 | */ |
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7 | |
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8 | /* |
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9 | * COPYRIGHT (c) 1989-2010. |
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10 | * On-Line Applications Research Corporation (OAR). |
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11 | * Copyright (c) 2016 embedded brains GmbH. |
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12 | * COPYRIGHT (c) 2016 Kuan-Hsun Chen. |
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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 | #if HAVE_CONFIG_H |
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20 | #include "config.h" |
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21 | #endif |
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22 | |
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23 | #include <rtems/rtems/ratemonimpl.h> |
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24 | #include <rtems/score/schedulerimpl.h> |
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25 | #include <rtems/score/todimpl.h> |
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26 | |
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27 | bool _Rate_monotonic_Get_status( |
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28 | const Rate_monotonic_Control *the_period, |
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29 | Timestamp_Control *wall_since_last_period, |
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30 | Timestamp_Control *cpu_since_last_period |
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31 | ) |
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32 | { |
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33 | Timestamp_Control uptime; |
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34 | Thread_Control *owning_thread = the_period->owner; |
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35 | Timestamp_Control used; |
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36 | |
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37 | /* |
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38 | * Determine elapsed wall time since period initiated. |
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39 | */ |
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40 | _TOD_Get_uptime( &uptime ); |
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41 | _Timestamp_Subtract( |
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42 | &the_period->time_period_initiated, &uptime, wall_since_last_period |
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43 | ); |
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44 | |
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45 | /* |
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46 | * Determine cpu usage since period initiated. |
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47 | */ |
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48 | _Thread_Get_CPU_time_used( owning_thread, &used ); |
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49 | |
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50 | /* |
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51 | * The cpu usage info was reset while executing. Can't |
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52 | * determine a status. |
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53 | */ |
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54 | if ( _Timestamp_Less_than( &used, &the_period->cpu_usage_period_initiated ) ) |
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55 | return false; |
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56 | |
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57 | /* used = current cpu usage - cpu usage at start of period */ |
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58 | _Timestamp_Subtract( |
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59 | &the_period->cpu_usage_period_initiated, |
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60 | &used, |
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61 | cpu_since_last_period |
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62 | ); |
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63 | |
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64 | return true; |
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65 | } |
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66 | |
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67 | static void _Rate_monotonic_Release_postponed_job( |
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68 | Rate_monotonic_Control *the_period, |
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69 | Thread_Control *owner, |
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70 | rtems_interval next_length, |
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71 | ISR_lock_Context *lock_context |
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72 | ) |
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73 | { |
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74 | Per_CPU_Control *cpu_self; |
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75 | Thread_queue_Context queue_context; |
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76 | |
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77 | --the_period->postponed_jobs; |
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78 | _Scheduler_Release_job( |
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79 | owner, |
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80 | &the_period->Priority, |
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81 | the_period->latest_deadline, |
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82 | &queue_context |
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83 | ); |
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84 | |
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85 | cpu_self = _Thread_Dispatch_disable_critical( lock_context ); |
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86 | _Rate_monotonic_Release( the_period, lock_context ); |
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87 | _Thread_Priority_update( &queue_context ); |
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88 | _Thread_Dispatch_direct( cpu_self ); |
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89 | } |
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90 | |
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91 | static void _Rate_monotonic_Release_job( |
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92 | Rate_monotonic_Control *the_period, |
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93 | Thread_Control *owner, |
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94 | rtems_interval next_length, |
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95 | ISR_lock_Context *lock_context |
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96 | ) |
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97 | { |
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98 | Per_CPU_Control *cpu_self; |
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99 | Thread_queue_Context queue_context; |
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100 | uint64_t deadline; |
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101 | |
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102 | cpu_self = _Thread_Dispatch_disable_critical( lock_context ); |
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103 | |
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104 | deadline = _Watchdog_Per_CPU_insert_ticks( |
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105 | &the_period->Timer, |
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106 | cpu_self, |
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107 | next_length |
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108 | ); |
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109 | _Scheduler_Release_job( |
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110 | owner, |
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111 | &the_period->Priority, |
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112 | deadline, |
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113 | &queue_context |
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114 | ); |
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115 | |
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116 | _Rate_monotonic_Release( the_period, lock_context ); |
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117 | _Thread_Priority_update( &queue_context ); |
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118 | _Thread_Dispatch_enable( cpu_self ); |
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119 | } |
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120 | |
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121 | void _Rate_monotonic_Restart( |
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122 | Rate_monotonic_Control *the_period, |
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123 | Thread_Control *owner, |
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124 | ISR_lock_Context *lock_context |
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125 | ) |
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126 | { |
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127 | /* |
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128 | * Set the starting point and the CPU time used for the statistics. |
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129 | */ |
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130 | _TOD_Get_uptime( &the_period->time_period_initiated ); |
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131 | _Thread_Get_CPU_time_used( owner, &the_period->cpu_usage_period_initiated ); |
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132 | |
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133 | _Rate_monotonic_Release_job( |
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134 | the_period, |
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135 | owner, |
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136 | the_period->next_length, |
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137 | lock_context |
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138 | ); |
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139 | } |
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140 | |
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141 | static void _Rate_monotonic_Update_statistics( |
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142 | Rate_monotonic_Control *the_period |
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143 | ) |
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144 | { |
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145 | Timestamp_Control executed; |
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146 | Timestamp_Control since_last_period; |
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147 | Rate_monotonic_Statistics *stats; |
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148 | bool valid_status; |
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149 | |
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150 | /* |
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151 | * Assume we are only called in states where it is appropriate |
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152 | * to update the statistics. This should only be RATE_MONOTONIC_ACTIVE |
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153 | * and RATE_MONOTONIC_EXPIRED. |
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154 | */ |
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155 | |
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156 | /* |
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157 | * Update the counts. |
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158 | */ |
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159 | stats = &the_period->Statistics; |
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160 | stats->count++; |
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161 | |
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162 | if ( the_period->state == RATE_MONOTONIC_EXPIRED ) |
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163 | stats->missed_count++; |
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164 | |
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165 | /* |
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166 | * Grab status for time statistics. |
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167 | */ |
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168 | valid_status = |
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169 | _Rate_monotonic_Get_status( the_period, &since_last_period, &executed ); |
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170 | if (!valid_status) |
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171 | return; |
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172 | |
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173 | /* |
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174 | * Update CPU time |
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175 | */ |
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176 | _Timestamp_Add_to( &stats->total_cpu_time, &executed ); |
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177 | |
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178 | if ( _Timestamp_Less_than( &executed, &stats->min_cpu_time ) ) |
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179 | stats->min_cpu_time = executed; |
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180 | |
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181 | if ( _Timestamp_Greater_than( &executed, &stats->max_cpu_time ) ) |
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182 | stats->max_cpu_time = executed; |
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183 | |
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184 | /* |
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185 | * Update Wall time |
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186 | */ |
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187 | _Timestamp_Add_to( &stats->total_wall_time, &since_last_period ); |
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188 | |
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189 | if ( _Timestamp_Less_than( &since_last_period, &stats->min_wall_time ) ) |
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190 | stats->min_wall_time = since_last_period; |
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191 | |
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192 | if ( _Timestamp_Greater_than( &since_last_period, &stats->max_wall_time ) ) |
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193 | stats->max_wall_time = since_last_period; |
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194 | } |
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195 | |
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196 | static rtems_status_code _Rate_monotonic_Get_status_for_state( |
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197 | rtems_rate_monotonic_period_states state |
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198 | ) |
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199 | { |
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200 | switch ( state ) { |
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201 | case RATE_MONOTONIC_INACTIVE: |
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202 | return RTEMS_NOT_DEFINED; |
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203 | case RATE_MONOTONIC_EXPIRED: |
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204 | return RTEMS_TIMEOUT; |
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205 | default: |
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206 | _Assert( state == RATE_MONOTONIC_ACTIVE ); |
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207 | return RTEMS_SUCCESSFUL; |
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208 | } |
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209 | } |
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210 | |
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211 | static rtems_status_code _Rate_monotonic_Activate( |
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212 | Rate_monotonic_Control *the_period, |
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213 | rtems_interval length, |
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214 | Thread_Control *executing, |
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215 | ISR_lock_Context *lock_context |
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216 | ) |
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217 | { |
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218 | the_period->postponed_jobs = 0; |
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219 | the_period->state = RATE_MONOTONIC_ACTIVE; |
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220 | the_period->next_length = length; |
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221 | _Rate_monotonic_Restart( the_period, executing, lock_context ); |
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222 | return RTEMS_SUCCESSFUL; |
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223 | } |
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224 | |
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225 | static rtems_status_code _Rate_monotonic_Block_while_active( |
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226 | Rate_monotonic_Control *the_period, |
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227 | rtems_interval length, |
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228 | Thread_Control *executing, |
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229 | ISR_lock_Context *lock_context |
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230 | ) |
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231 | { |
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232 | Per_CPU_Control *cpu_self; |
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233 | bool success; |
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234 | |
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235 | /* |
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236 | * Update statistics from the concluding period. |
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237 | */ |
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238 | _Rate_monotonic_Update_statistics( the_period ); |
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239 | |
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240 | /* |
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241 | * This tells the _Rate_monotonic_Timeout that this task is |
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242 | * in the process of blocking on the period and that we |
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243 | * may be changing the length of the next period. |
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244 | */ |
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245 | the_period->next_length = length; |
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246 | executing->Wait.return_argument = the_period; |
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247 | _Thread_Wait_flags_set( executing, RATE_MONOTONIC_INTEND_TO_BLOCK ); |
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248 | |
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249 | cpu_self = _Thread_Dispatch_disable_critical( lock_context ); |
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250 | _Rate_monotonic_Release( the_period, lock_context ); |
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251 | |
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252 | _Thread_Set_state( executing, STATES_WAITING_FOR_PERIOD ); |
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253 | |
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254 | success = _Thread_Wait_flags_try_change_acquire( |
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255 | executing, |
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256 | RATE_MONOTONIC_INTEND_TO_BLOCK, |
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257 | RATE_MONOTONIC_BLOCKED |
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258 | ); |
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259 | if ( !success ) { |
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260 | _Assert( |
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261 | _Thread_Wait_flags_get( executing ) == RATE_MONOTONIC_READY_AGAIN |
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262 | ); |
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263 | _Thread_Unblock( executing ); |
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264 | } |
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265 | |
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266 | _Thread_Dispatch_direct( cpu_self ); |
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267 | return RTEMS_SUCCESSFUL; |
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268 | } |
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269 | |
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270 | /* |
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271 | * There are two possible cases: one is that the previous deadline is missed, |
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272 | * The other is that the number of postponed jobs is not 0, but the current |
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273 | * deadline is still not expired, i.e., state = RATE_MONOTONIC_ACTIVE. |
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274 | */ |
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275 | static rtems_status_code _Rate_monotonic_Block_while_expired( |
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276 | Rate_monotonic_Control *the_period, |
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277 | rtems_interval length, |
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278 | Thread_Control *executing, |
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279 | ISR_lock_Context *lock_context |
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280 | ) |
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281 | { |
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282 | /* |
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283 | * No matter the just finished jobs in time or not, |
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284 | * they are actually missing their deadlines already. |
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285 | */ |
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286 | the_period->state = RATE_MONOTONIC_EXPIRED; |
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287 | |
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288 | /* |
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289 | * Update statistics from the concluding period |
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290 | */ |
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291 | _Rate_monotonic_Update_statistics( the_period ); |
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292 | |
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293 | the_period->state = RATE_MONOTONIC_ACTIVE; |
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294 | the_period->next_length = length; |
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295 | |
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296 | _Rate_monotonic_Release_postponed_job( |
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297 | the_period, |
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298 | executing, |
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299 | length, |
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300 | lock_context |
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301 | ); |
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302 | return RTEMS_TIMEOUT; |
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303 | } |
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304 | |
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305 | rtems_status_code rtems_rate_monotonic_period( |
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306 | rtems_id id, |
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307 | rtems_interval length |
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308 | ) |
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309 | { |
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310 | Rate_monotonic_Control *the_period; |
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311 | ISR_lock_Context lock_context; |
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312 | Thread_Control *executing; |
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313 | rtems_status_code status; |
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314 | rtems_rate_monotonic_period_states state; |
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315 | |
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316 | the_period = _Rate_monotonic_Get( id, &lock_context ); |
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317 | if ( the_period == NULL ) { |
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318 | return RTEMS_INVALID_ID; |
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319 | } |
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320 | |
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321 | executing = _Thread_Executing; |
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322 | if ( executing != the_period->owner ) { |
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323 | _ISR_lock_ISR_enable( &lock_context ); |
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324 | return RTEMS_NOT_OWNER_OF_RESOURCE; |
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325 | } |
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326 | |
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327 | _Rate_monotonic_Acquire_critical( the_period, &lock_context ); |
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328 | |
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329 | state = the_period->state; |
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330 | |
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331 | if ( length == RTEMS_PERIOD_STATUS ) { |
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332 | status = _Rate_monotonic_Get_status_for_state( state ); |
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333 | _Rate_monotonic_Release( the_period, &lock_context ); |
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334 | } else { |
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335 | switch ( state ) { |
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336 | case RATE_MONOTONIC_ACTIVE: |
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337 | |
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338 | if( the_period->postponed_jobs > 0 ){ |
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339 | /* |
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340 | * If the number of postponed jobs is not 0, it means the |
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341 | * previous postponed instance is finished without exceeding |
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342 | * the current period deadline. |
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343 | * |
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344 | * Do nothing on the watchdog deadline assignment but release the |
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345 | * next remaining postponed job. |
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346 | */ |
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347 | status = _Rate_monotonic_Block_while_expired( |
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348 | the_period, |
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349 | length, |
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350 | executing, |
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351 | &lock_context |
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352 | ); |
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353 | }else{ |
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354 | /* |
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355 | * Normal case that no postponed jobs and no expiration, so wait for |
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356 | * the period and update the deadline of watchdog accordingly. |
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357 | */ |
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358 | status = _Rate_monotonic_Block_while_active( |
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359 | the_period, |
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360 | length, |
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361 | executing, |
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362 | &lock_context |
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363 | ); |
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364 | } |
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365 | break; |
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366 | case RATE_MONOTONIC_INACTIVE: |
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367 | status = _Rate_monotonic_Activate( |
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368 | the_period, |
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369 | length, |
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370 | executing, |
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371 | &lock_context |
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372 | ); |
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373 | break; |
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374 | default: |
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375 | /* |
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376 | * As now this period was already TIMEOUT, there must be at least one |
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377 | * postponed job recorded by the watchdog. The one which exceeded |
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378 | * the previous deadlines was just finished. |
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379 | * |
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380 | * Maybe there is more than one job postponed due to the preemption or |
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381 | * the previous finished job. |
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382 | */ |
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383 | _Assert( state == RATE_MONOTONIC_EXPIRED ); |
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384 | status = _Rate_monotonic_Block_while_expired( |
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385 | the_period, |
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386 | length, |
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387 | executing, |
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388 | &lock_context |
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389 | ); |
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390 | break; |
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391 | } |
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392 | } |
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393 | |
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394 | return status; |
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395 | } |
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