1 | /* |
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2 | * scheduler.c - Core scheduler implementation. |
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3 | * |
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4 | * Author Alain Greiner (2016) |
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5 | * |
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6 | * Copyright (c) UPMC Sorbonne Universites |
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7 | * |
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8 | * This file is part of ALMOS-MKH. |
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9 | * |
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10 | * ALMOS-MKH. is free software; you can redistribute it and/or modify it |
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11 | * under the terms of the GNU General Public License as published by |
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12 | * the Free Software Foundation; version 2.0 of the License. |
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13 | * |
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14 | * ALMOS-MKH. is distributed in the hope that it will be useful, but |
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15 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
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16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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17 | * General Public License for more details. |
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18 | * |
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19 | * You should have received a copy of the GNU General Public License |
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20 | * along with ALMOS-MKH.; if not, write to the Free Software Foundation, |
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21 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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22 | */ |
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23 | |
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24 | #include <kernel_config.h> |
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25 | #include <hal_types.h> |
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26 | #include <hal_irqmask.h> |
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27 | #include <hal_context.h> |
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28 | #include <printk.h> |
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29 | #include <list.h> |
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30 | #include <core.h> |
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31 | #include <thread.h> |
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32 | #include <chdev.h> |
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33 | #include <scheduler.h> |
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34 | |
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35 | /////////////////////////////////////////////////////////////////////////////////////////// |
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36 | // Extern global variables |
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37 | /////////////////////////////////////////////////////////////////////////////////////////// |
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38 | |
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39 | extern chdev_directory_t chdev_dir; // allocated in kernel_init.c file |
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40 | |
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41 | |
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42 | //////////////////////////////// |
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43 | void sched_init( core_t * core ) |
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44 | { |
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45 | scheduler_t * sched = &core->scheduler; |
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46 | |
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47 | sched->u_threads_nr = 0; |
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48 | sched->k_threads_nr = 0; |
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49 | |
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50 | sched->current = CURRENT_THREAD; |
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51 | sched->idle = NULL; // initialized in kernel_init() |
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52 | sched->u_last = NULL; // initialized in sched_register_thread() |
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53 | sched->k_last = NULL; // initialized in sched_register_thread() |
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54 | |
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55 | // initialise threads lists |
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56 | list_root_init( &sched->u_root ); |
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57 | list_root_init( &sched->k_root ); |
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58 | |
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59 | } // end sched_init() |
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60 | |
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61 | //////////////////////////////////////////// |
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62 | void sched_register_thread( core_t * core, |
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63 | thread_t * thread ) |
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64 | { |
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65 | scheduler_t * sched = &core->scheduler; |
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66 | thread_type_t type = thread->type; |
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67 | |
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68 | // take lock protecting sheduler lists |
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69 | spinlock_lock( &sched->lock ); |
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70 | |
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71 | if( type == THREAD_USER ) |
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72 | { |
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73 | // register thread in scheduler user list |
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74 | list_add_last( &sched->u_root , &thread->sched_list ); |
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75 | sched->u_threads_nr++; |
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76 | |
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77 | // initialize u_last field if first user thread |
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78 | if( sched->u_last == NULL ) sched->u_last = &thread->sched_list; |
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79 | } |
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80 | else // kernel thread |
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81 | { |
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82 | // register thread in scheduler kernel list |
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83 | list_add_last( &sched->k_root , &thread->sched_list ); |
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84 | sched->k_threads_nr++; |
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85 | |
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86 | // initialize k_last field if first kernel thread |
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87 | if( sched->k_last == NULL ) sched->k_last = &thread->sched_list; |
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88 | } |
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89 | |
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90 | // release lock |
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91 | spinlock_unlock( &sched->lock ); |
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92 | |
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93 | } // end sched_register() |
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94 | |
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95 | ///////////////////////////////////////////// |
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96 | void sched_remove_thread( thread_t * thread ) |
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97 | { |
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98 | core_t * core = thread->core; |
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99 | scheduler_t * sched = &core->scheduler; |
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100 | thread_type_t type = thread->type; |
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101 | |
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102 | // take lock protecting sheduler lists |
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103 | spinlock_lock( &sched->lock ); |
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104 | |
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105 | if( type == THREAD_USER ) |
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106 | { |
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107 | // remove thread from user list |
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108 | list_unlink( &thread->sched_list ); |
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109 | sched->u_threads_nr--; |
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110 | |
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111 | // reset the u_last field if list empty |
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112 | if( sched->u_threads_nr == 0 ) sched->u_last = NULL; |
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113 | } |
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114 | else // kernel thread |
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115 | { |
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116 | // remove thread from kernel list |
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117 | list_unlink( &thread->sched_list ); |
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118 | sched->k_threads_nr--; |
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119 | |
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120 | // reset the k_last field if list empty |
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121 | if( sched->k_threads_nr == 0 ) sched->k_last = NULL; |
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122 | } |
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123 | |
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124 | // release lock |
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125 | spinlock_unlock( &sched->lock ); |
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126 | |
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127 | } // end sched_remove() |
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128 | |
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129 | /////////////////////////////////////////// |
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130 | void sched_kill_thread( thread_t * thread ) |
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131 | { |
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132 | // check thread locks |
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133 | if( thread_can_yield() == false ) |
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134 | { |
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135 | printk("\n[PANIC] in %s : thread %x in process %x on core[%x][%d]" |
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136 | " did not released all locks\n", |
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137 | __FUNCTION__ , thread->trdid , thread->process->pid, |
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138 | local_cxy , thread->core->lid ); |
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139 | hal_core_sleep(); |
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140 | } |
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141 | |
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142 | // remove thread from scheduler |
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143 | sched_remove_thread( thread ); |
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144 | |
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145 | // reset the THREAD_SIG_KILL signal |
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146 | thread_reset_signal( thread , THREAD_SIG_KILL ); |
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147 | |
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148 | } // end sched_kill_thread() |
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149 | |
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150 | //////////////////////////////////////// |
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151 | thread_t * sched_select( core_t * core ) |
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152 | { |
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153 | thread_t * thread; |
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154 | |
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155 | scheduler_t * sched = &core->scheduler; |
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156 | |
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157 | sched_dmsg("\n[INFO] %s : enter core[%x,%d] / cycle %d\n", |
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158 | __FUNCTION__ , local_cxy , core->lid , hal_time_stamp() ); |
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159 | |
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160 | // take lock protecting sheduler lists |
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161 | spinlock_lock( &sched->lock ); |
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162 | |
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163 | list_entry_t * current; |
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164 | list_entry_t * last; |
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165 | |
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166 | // first : scan the kernel threads list if not empty |
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167 | if( list_is_empty( &sched->k_root ) == false ) |
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168 | { |
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169 | last = sched->k_last; |
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170 | current = sched->k_last; |
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171 | do |
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172 | { |
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173 | // get next entry in kernel list |
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174 | current = list_next( &sched->k_root , current ); |
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175 | |
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176 | // skip the root that does not contain a thread |
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177 | if( current == NULL ) current = sched->k_root.next; |
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178 | |
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179 | // get thread pointer for this entry |
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180 | thread = LIST_ELEMENT( current , thread_t , sched_list ); |
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181 | |
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182 | // return thread if not idle_thread and runnable |
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183 | if( (thread->type != THREAD_IDLE) && (thread->blocked == 0) ) |
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184 | { |
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185 | // release lock |
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186 | spinlock_unlock( &sched->lock ); |
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187 | |
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188 | sched_dmsg("\n[INFO] %s : exit core[%x,%d] / k_thread = %x / cycle %d\n", |
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189 | __FUNCTION__ , local_cxy , core->lid , thread->trdid , hal_time_stamp() ); |
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190 | |
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191 | return thread; |
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192 | } |
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193 | } |
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194 | while( current != last ); |
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195 | } |
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196 | |
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197 | // second : scan the user threads list if not empty |
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198 | if( list_is_empty( &sched->u_root ) == false ) |
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199 | { |
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200 | last = sched->u_last; |
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201 | current = sched->u_last; |
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202 | do |
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203 | { |
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204 | // get next entry in user list |
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205 | current = list_next( &sched->u_root , current ); |
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206 | |
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207 | // skip the root that does not contain a thread |
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208 | if( current == NULL ) current = sched->u_root.next; |
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209 | |
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210 | // get thread pointer for this entry |
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211 | thread = LIST_ELEMENT( current , thread_t , sched_list ); |
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212 | |
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213 | // return thread if runnable |
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214 | if( thread->blocked == 0 ) |
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215 | { |
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216 | // release lock |
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217 | spinlock_unlock( &sched->lock ); |
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218 | |
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219 | sched_dmsg("\n[INFO] %s : exit core[%x,%d] / u_thread = %x / cycle %d\n", |
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220 | __FUNCTION__ , local_cxy , core->lid , thread->trdid , hal_time_stamp() ); |
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221 | return thread; |
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222 | } |
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223 | } |
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224 | while( current != last ); |
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225 | } |
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226 | |
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227 | // release lock |
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228 | spinlock_unlock( &sched->lock ); |
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229 | |
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230 | sched_dmsg("\n[INFO] %s : exit core[%x,%d] / idle = %x / cycle %d\n", |
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231 | __FUNCTION__ , local_cxy , core->lid , sched->idle->trdid , hal_time_stamp() ); |
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232 | |
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233 | // third : return idle thread if no runnable thread |
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234 | return sched->idle; |
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235 | |
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236 | } // end sched_select() |
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237 | |
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238 | ////////////////////////////////////////// |
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239 | void sched_handle_signals( core_t * core ) |
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240 | { |
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241 | list_entry_t * iter; |
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242 | thread_t * thread; |
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243 | scheduler_t * sched = &core->scheduler; |
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244 | |
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245 | sched_dmsg("\n[INFO] %s : enter / thread %x on core[%x,%d]\n", |
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246 | __FUNCTION__, CURRENT_THREAD->trdid , local_cxy , core->lid ); |
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247 | |
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248 | // take lock protecting threads lists |
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249 | spinlock_lock( &sched->lock ); |
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250 | |
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251 | // handle user threads |
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252 | LIST_FOREACH( &sched->u_root , iter ) |
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253 | { |
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254 | thread = LIST_ELEMENT( iter , thread_t , sched_list ); |
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255 | if( thread->signals & THREAD_SIG_KILL ) sched_kill_thread( thread ); |
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256 | } |
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257 | |
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258 | // handle kernel threads |
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259 | LIST_FOREACH( &sched->k_root , iter ) |
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260 | { |
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261 | thread = LIST_ELEMENT( iter , thread_t , sched_list ); |
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262 | if( thread->signals & THREAD_SIG_KILL ) sched_kill_thread( thread ); |
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263 | } |
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264 | |
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265 | // release lock |
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266 | spinlock_unlock( &sched->lock ); |
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267 | |
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268 | sched_dmsg("\n[INFO] %s : exit / thread %x on core[%x,%d]\n", |
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269 | __FUNCTION__, CURRENT_THREAD->trdid , local_cxy , core->lid ); |
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270 | |
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271 | } // end sched_handle_signals() |
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272 | |
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273 | /////////////////////////////////// |
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274 | void sched_yield( thread_t * next ) |
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275 | { |
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276 | reg_t sr_save; |
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277 | |
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278 | thread_t * current = CURRENT_THREAD; |
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279 | core_t * core = current->core; |
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280 | scheduler_t * sched = &core->scheduler; |
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281 | |
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282 | sched_dmsg("\n[INFO] %s : thread %x on core[%x,%d] enter / cycle %d\n", |
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283 | __FUNCTION__, current->trdid, local_cxy, core->lid, hal_time_stamp() ); |
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284 | |
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285 | // check calling thread released all locks |
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286 | assert( (thread_can_yield() == true), __FUNCTION__, "locks not released\n"); |
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287 | |
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288 | // first loop on all threads to handle pending signals |
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289 | sched_handle_signals( core ); |
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290 | |
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291 | // second loop on threads to select next thread if required |
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292 | if( next == NULL ) next = sched_select( core ); |
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293 | |
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294 | // check next thread attached to same core as the calling thread |
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295 | assert( (next->core == current->core), __FUNCTION__ , "next core != current core\n"); |
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296 | |
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297 | // check next thread not blocked |
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298 | assert( (next->blocked == 0), __FUNCTION__ , "next thread is blocked\n"); |
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299 | |
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300 | // switch contexts and update scheduler state if next != current |
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301 | if( next != current ) |
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302 | { |
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303 | sched_dmsg("\n[INFO] %s : trd %x (%s) on core[%x,%d] => trd %x (%s) / cycle %d\n", |
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304 | __FUNCTION__, current->trdid, thread_type_str(current->type), local_cxy, core->lid, |
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305 | next->trdid, thread_type_str(next->type), hal_time_stamp() ); |
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306 | |
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307 | // calling thread desactivate IRQs |
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308 | hal_disable_irq( &sr_save ); |
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309 | |
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310 | // update scheduler |
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311 | if( current->type == THREAD_USER ) sched->u_last = ¤t->sched_list; |
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312 | else sched->k_last = ¤t->sched_list; |
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313 | sched->current = next; |
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314 | |
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315 | // handle FPU |
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316 | if( next->type == THREAD_USER ) |
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317 | { |
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318 | if( next == core->fpu_owner ) hal_fpu_enable(); |
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319 | else hal_fpu_disable(); |
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320 | } |
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321 | |
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322 | // switch contexts |
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323 | hal_cpu_context_save( current->cpu_context ); |
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324 | hal_cpu_context_restore( next->cpu_context ); |
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325 | |
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326 | // restore IRQs when calling thread resume |
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327 | hal_restore_irq( sr_save ); |
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328 | |
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329 | sched_dmsg("\n[INFO] %s : thread %x on core[%x,%d] / cycle %d\n", |
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330 | __FUNCTION__, current->trdid, local_cxy, core->lid, hal_time_stamp() ); |
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331 | } |
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332 | else |
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333 | { |
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334 | sched_dmsg("\n[INFO] %s : thread %x on core[%x,%d] continue / cycle %d\n", |
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335 | __FUNCTION__, current->trdid, local_cxy, core->lid, hal_time_stamp() ); |
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336 | } |
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337 | } // end sched_yield() |
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338 | |
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339 | //////////////////// |
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340 | void sched_display() |
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341 | { |
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342 | list_entry_t * iter; |
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343 | thread_t * thread; |
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344 | uint32_t save_sr; |
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345 | |
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346 | thread_t * current = CURRENT_THREAD; |
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347 | core_t * core = current->core; |
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348 | scheduler_t * sched = &core->scheduler; |
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349 | |
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350 | // get pointers on TXT0 chdev |
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351 | xptr_t txt0_xp = chdev_dir.txt[0]; |
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352 | cxy_t txt0_cxy = GET_CXY( txt0_xp ); |
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353 | chdev_t * txt0_ptr = GET_PTR( txt0_xp ); |
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354 | |
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355 | // get extended pointer on remote TXT0 chdev lock |
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356 | xptr_t lock_xp = XPTR( txt0_cxy , &txt0_ptr->wait_lock ); |
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357 | |
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358 | // get TXT0 lock in busy waiting mode |
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359 | remote_spinlock_lock_busy( lock_xp , &save_sr ); |
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360 | |
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361 | nolock_printk("\n********** scheduler state for core[%x,%d] **********************\n" |
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362 | "kernel_threads = %d / user_threads = %d / current = %x\n", |
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363 | local_cxy , core->lid, |
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364 | sched->k_threads_nr, sched->u_threads_nr, sched->current->trdid ); |
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365 | |
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366 | // display kernel threads |
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367 | LIST_FOREACH( &sched->k_root , iter ) |
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368 | { |
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369 | thread = LIST_ELEMENT( iter , thread_t , sched_list ); |
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370 | nolock_printk(" - type = %s / trdid = %x / pid = %x / func = %x / blocked_vect = %x\n", |
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371 | thread_type_str( thread->type ), thread->trdid, thread->process->pid, |
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372 | thread->entry_func, thread->blocked ); |
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373 | } |
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374 | |
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375 | // display user threads |
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376 | LIST_FOREACH( &sched->u_root , iter ) |
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377 | { |
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378 | thread = LIST_ELEMENT( iter , thread_t , sched_list ); |
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379 | nolock_printk(" - type = %s / trdid = %x / pid = %x / func = %x / blocked_vect = %x\n", |
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380 | thread_type_str( thread->type ), thread->trdid, thread->process->pid, |
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381 | thread->entry_func, thread->blocked ); |
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382 | } |
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383 | |
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384 | // release TXT0 lock |
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385 | remote_spinlock_unlock_busy( lock_xp , save_sr ); |
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386 | |
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387 | } // end sched_display() |
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388 | |
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