1 | // -*- Mode: CFA -*- |
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2 | // |
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3 | // Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo |
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4 | // |
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5 | // The contents of this file are covered under the licence agreement in the |
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6 | // file "LICENCE" distributed with Cforall. |
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7 | // |
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8 | // monitor_desc.c -- |
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9 | // |
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10 | // Author : Thierry Delisle |
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11 | // Created On : Thd Feb 23 12:27:26 2017 |
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12 | // Last Modified By : Thierry Delisle |
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13 | // Last Modified On : -- |
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14 | // Update Count : 0 |
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15 | // |
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16 | |
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17 | #include "monitor" |
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18 | |
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19 | #include <stdlib> |
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20 | |
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21 | #include "kernel_private.h" |
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22 | #include "libhdr.h" |
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23 | |
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24 | //----------------------------------------------------------------------------- |
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25 | // Forward declarations |
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26 | static inline void set_owner( monitor_desc * this, thread_desc * owner ); |
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27 | static inline thread_desc * next_thread( monitor_desc * this ); |
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28 | |
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29 | static inline void lock_all( spinlock ** locks, unsigned short count ); |
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30 | static inline void lock_all( monitor_desc ** source, spinlock ** /*out*/ locks, unsigned short count ); |
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31 | static inline void unlock_all( spinlock ** locks, unsigned short count ); |
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32 | static inline void unlock_all( monitor_desc ** locks, unsigned short count ); |
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33 | |
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34 | static inline void save_recursion ( monitor_desc ** ctx, unsigned int * /*out*/ recursions, unsigned short count ); |
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35 | static inline void restore_recursion( monitor_desc ** ctx, unsigned int * /*in */ recursions, unsigned short count ); |
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36 | |
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37 | static inline thread_desc * check_condition( __condition_criterion_t * ); |
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38 | static inline void brand_condition( condition * ); |
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39 | static inline unsigned short insert_unique( thread_desc ** thrds, unsigned short end, thread_desc * val ); |
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40 | |
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41 | //----------------------------------------------------------------------------- |
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42 | // Enter/Leave routines |
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43 | |
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44 | |
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45 | extern "C" { |
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46 | void __enter_monitor_desc(monitor_desc * this) { |
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47 | lock( &this->lock ); |
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48 | thread_desc * thrd = this_thread(); |
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49 | |
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50 | LIB_DEBUG_PRINT_SAFE("%p Entering %p (o: %p, r: %i)\n", thrd, this, this->owner, this->recursion); |
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51 | |
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52 | if( !this->owner ) { |
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53 | //No one has the monitor, just take it |
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54 | set_owner( this, thrd ); |
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55 | } |
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56 | else if( this->owner == thrd) { |
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57 | //We already have the monitor, just not how many times we took it |
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58 | assert( this->recursion > 0 ); |
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59 | this->recursion += 1; |
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60 | } |
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61 | else { |
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62 | //Some one else has the monitor, wait in line for it |
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63 | append( &this->entry_queue, thrd ); |
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64 | LIB_DEBUG_PRINT_SAFE("%p Blocking on entry\n", thrd); |
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65 | ScheduleInternal( &this->lock ); |
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66 | |
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67 | //ScheduleInternal will unlock spinlock, no need to unlock ourselves |
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68 | return; |
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69 | } |
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70 | |
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71 | unlock( &this->lock ); |
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72 | return; |
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73 | } |
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74 | |
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75 | // leave pseudo code : |
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76 | // TODO |
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77 | void __leave_monitor_desc(monitor_desc * this) { |
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78 | lock( &this->lock ); |
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79 | |
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80 | thread_desc * thrd = this_thread(); |
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81 | |
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82 | LIB_DEBUG_PRINT_SAFE("%p Leaving %p (o: %p, r: %i)\n", thrd, this, this->owner, this->recursion); |
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83 | assertf( thrd == this->owner, "Expected owner to be %p, got %p (r: %i)", thrd, this->owner, this->recursion ); |
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84 | |
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85 | //Leaving a recursion level, decrement the counter |
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86 | this->recursion -= 1; |
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87 | |
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88 | //If we haven't left the last level of recursion |
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89 | //it means we don't need to do anything |
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90 | if( this->recursion != 0) { |
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91 | unlock( &this->lock ); |
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92 | return; |
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93 | } |
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94 | |
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95 | thread_desc * new_owner = next_thread( this ); |
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96 | |
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97 | //We can now let other threads in safely |
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98 | unlock( &this->lock ); |
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99 | |
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100 | LIB_DEBUG_PRINT_SAFE("Next owner is %p\n", new_owner); |
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101 | |
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102 | //We need to wake-up the thread |
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103 | ScheduleThread( new_owner ); |
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104 | } |
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105 | } |
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106 | |
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107 | static inline void enter(monitor_desc ** monitors, int count) { |
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108 | for(int i = 0; i < count; i++) { |
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109 | __enter_monitor_desc( monitors[i] ); |
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110 | } |
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111 | } |
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112 | |
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113 | static inline void leave(monitor_desc ** monitors, int count) { |
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114 | for(int i = count - 1; i >= 0; i--) { |
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115 | __leave_monitor_desc( monitors[i] ); |
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116 | } |
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117 | } |
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118 | |
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119 | void ?{}( monitor_guard_t * this, monitor_desc ** m, int count ) { |
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120 | this->m = m; |
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121 | this->count = count; |
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122 | qsort(this->m, count); |
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123 | enter( this->m, this->count ); |
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124 | |
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125 | this->prev_mntrs = this_thread()->current_monitors; |
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126 | this->prev_count = this_thread()->current_monitor_count; |
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127 | |
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128 | this_thread()->current_monitors = m; |
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129 | this_thread()->current_monitor_count = count; |
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130 | } |
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131 | |
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132 | void ^?{}( monitor_guard_t * this ) { |
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133 | leave( this->m, this->count ); |
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134 | |
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135 | this_thread()->current_monitors = this->prev_mntrs; |
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136 | this_thread()->current_monitor_count = this->prev_count; |
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137 | } |
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138 | |
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139 | void ?{}(__condition_node_t * this, thread_desc * waiting_thread, unsigned short count, uintptr_t user_info ) { |
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140 | this->waiting_thread = waiting_thread; |
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141 | this->count = count; |
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142 | this->next = NULL; |
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143 | this->user_info = user_info; |
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144 | } |
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145 | |
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146 | void ?{}(__condition_criterion_t * this ) { |
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147 | this->ready = false; |
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148 | this->target = NULL; |
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149 | this->owner = NULL; |
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150 | this->next = NULL; |
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151 | } |
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152 | |
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153 | void ?{}(__condition_criterion_t * this, monitor_desc * target, __condition_node_t * owner ) { |
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154 | this->ready = false; |
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155 | this->target = target; |
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156 | this->owner = owner; |
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157 | this->next = NULL; |
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158 | } |
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159 | |
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160 | //----------------------------------------------------------------------------- |
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161 | // Internal scheduling |
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162 | void wait( condition * this, uintptr_t user_info = 0 ) { |
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163 | LIB_DEBUG_PRINT_SAFE("Waiting\n"); |
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164 | |
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165 | brand_condition( this ); |
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166 | |
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167 | //Check that everything is as expected |
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168 | assertf( this->monitors != NULL, "Waiting with no monitors (%p)", this->monitors ); |
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169 | assertf( this->monitor_count != 0, "Waiting with 0 monitors (%i)", this->monitor_count ); |
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170 | assertf( this->monitor_count < 32u, "Excessive monitor count (%i)", this->monitor_count ); |
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171 | |
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172 | unsigned short count = this->monitor_count; |
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173 | unsigned int recursions[ count ]; //Save the current recursion levels to restore them later |
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174 | spinlock * locks [ count ]; //We need to pass-in an array of locks to ScheduleInternal |
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175 | |
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176 | LIB_DEBUG_PRINT_SAFE("count %i\n", count); |
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177 | |
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178 | __condition_node_t waiter = { this_thread(), count, user_info }; |
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179 | |
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180 | __condition_criterion_t criteria[count]; |
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181 | for(int i = 0; i < count; i++) { |
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182 | (&criteria[i]){ this->monitors[i], &waiter }; |
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183 | LIB_DEBUG_PRINT_SAFE( "Criterion %p\n", &criteria[i] ); |
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184 | } |
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185 | |
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186 | waiter.criteria = criteria; |
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187 | append( &this->blocked, &waiter ); |
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188 | |
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189 | lock_all( this->monitors, locks, count ); |
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190 | save_recursion( this->monitors, recursions, count ); |
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191 | //DON'T unlock, ask the kernel to do it |
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192 | |
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193 | //Find the next thread(s) to run |
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194 | unsigned short thread_count = 0; |
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195 | thread_desc * threads[ count ]; |
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196 | for(int i = 0; i < count; i++) { |
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197 | threads[i] = 0; |
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198 | } |
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199 | |
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200 | for( int i = 0; i < count; i++) { |
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201 | thread_desc * new_owner = next_thread( this->monitors[i] ); |
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202 | thread_count = insert_unique( threads, thread_count, new_owner ); |
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203 | } |
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204 | |
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205 | LIB_DEBUG_PRINT_SAFE("Will unblock: "); |
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206 | for(int i = 0; i < thread_count; i++) { |
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207 | LIB_DEBUG_PRINT_SAFE("%p ", threads[i]); |
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208 | } |
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209 | LIB_DEBUG_PRINT_SAFE("\n"); |
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210 | |
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211 | // Everything is ready to go to sleep |
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212 | ScheduleInternal( locks, count, threads, thread_count ); |
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213 | |
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214 | //WE WOKE UP |
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215 | |
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216 | |
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217 | //We are back, restore the owners and recursions |
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218 | lock_all( locks, count ); |
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219 | restore_recursion( this->monitors, recursions, count ); |
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220 | unlock_all( locks, count ); |
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221 | } |
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222 | |
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223 | bool signal( condition * this ) { |
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224 | if( is_empty( this ) ) { |
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225 | LIB_DEBUG_PRINT_SAFE("Nothing to signal\n"); |
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226 | return false; |
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227 | } |
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228 | |
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229 | //Check that everything is as expected |
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230 | assert( this->monitors ); |
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231 | assert( this->monitor_count != 0 ); |
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232 | |
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233 | unsigned short count = this->monitor_count; |
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234 | |
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235 | //Some more checking in debug |
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236 | LIB_DEBUG_DO( |
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237 | thread_desc * this_thrd = this_thread(); |
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238 | if ( this->monitor_count != this_thrd->current_monitor_count ) { |
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239 | abortf( "Signal on condition %p made with different number of monitor(s), expected %i got %i", this, this->monitor_count, this_thrd->current_monitor_count ); |
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240 | } // if |
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241 | |
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242 | for(int i = 0; i < this->monitor_count; i++) { |
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243 | if ( this->monitors[i] != this_thrd->current_monitors[i] ) { |
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244 | abortf( "Signal on condition %p made with different monitor, expected %p got %i", this, this->monitors[i], this_thrd->current_monitors[i] ); |
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245 | } // if |
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246 | } |
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247 | ); |
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248 | |
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249 | //Lock all the monitors |
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250 | lock_all( this->monitors, NULL, count ); |
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251 | LIB_DEBUG_PRINT_SAFE("Signalling"); |
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252 | |
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253 | //Pop the head of the waiting queue |
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254 | __condition_node_t * node = pop_head( &this->blocked ); |
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255 | |
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256 | //Add the thread to the proper AS stack |
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257 | for(int i = 0; i < count; i++) { |
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258 | __condition_criterion_t * crit = &node->criteria[i]; |
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259 | LIB_DEBUG_PRINT_SAFE(" %p", crit->target); |
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260 | assert( !crit->ready ); |
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261 | push( &crit->target->signal_stack, crit ); |
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262 | } |
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263 | |
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264 | LIB_DEBUG_PRINT_SAFE("\n"); |
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265 | |
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266 | //Release |
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267 | unlock_all( this->monitors, count ); |
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268 | |
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269 | return true; |
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270 | } |
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271 | |
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272 | bool signal_block( condition * this ) { |
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273 | if( !this->blocked.head ) { |
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274 | LIB_DEBUG_PRINT_SAFE("Nothing to signal\n"); |
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275 | return false; |
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276 | } |
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277 | |
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278 | //Check that everything is as expected |
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279 | assertf( this->monitors != NULL, "Waiting with no monitors (%p)", this->monitors ); |
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280 | assertf( this->monitor_count != 0, "Waiting with 0 monitors (%i)", this->monitor_count ); |
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281 | |
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282 | unsigned short count = this->monitor_count; |
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283 | unsigned int recursions[ count ]; //Save the current recursion levels to restore them later |
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284 | spinlock * locks [ count ]; //We need to pass-in an array of locks to ScheduleInternal |
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285 | |
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286 | lock_all( this->monitors, locks, count ); |
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287 | |
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288 | //create creteria |
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289 | __condition_node_t waiter = { this_thread(), count, 0 }; |
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290 | |
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291 | __condition_criterion_t criteria[count]; |
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292 | for(int i = 0; i < count; i++) { |
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293 | (&criteria[i]){ this->monitors[i], &waiter }; |
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294 | LIB_DEBUG_PRINT_SAFE( "Criterion %p\n", &criteria[i] ); |
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295 | push( &criteria[i].target->signal_stack, &criteria[i] ); |
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296 | } |
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297 | |
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298 | waiter.criteria = criteria; |
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299 | |
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300 | //save contexts |
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301 | save_recursion( this->monitors, recursions, count ); |
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302 | |
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303 | //Find the thread to run |
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304 | thread_desc * signallee = pop_head( &this->blocked )->waiting_thread; |
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305 | for(int i = 0; i < count; i++) { |
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306 | set_owner( this->monitors[i], signallee ); |
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307 | } |
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308 | |
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309 | LIB_DEBUG_PRINT_SAFE( "Waiting on signal block\n" ); |
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310 | |
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311 | //Everything is ready to go to sleep |
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312 | ScheduleInternal( locks, count, &signallee, 1 ); |
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313 | |
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314 | LIB_DEBUG_PRINT_SAFE( "Back from signal block\n" ); |
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315 | |
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316 | //We are back, restore the owners and recursions |
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317 | lock_all( locks, count ); |
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318 | restore_recursion( this->monitors, recursions, count ); |
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319 | unlock_all( locks, count ); |
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320 | |
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321 | return true; |
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322 | } |
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323 | |
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324 | uintptr_t front( condition * this ) { |
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325 | LIB_DEBUG_DO( |
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326 | if( is_empty(this) ) { |
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327 | abortf( "Attempt to access user data on an empty condition.\n" |
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328 | "Possible cause is not checking if the condition is empty before reading stored data." ); |
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329 | } |
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330 | ); |
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331 | return this->blocked.head->user_info; |
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332 | } |
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333 | |
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334 | //----------------------------------------------------------------------------- |
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335 | // Utilities |
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336 | |
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337 | static inline void set_owner( monitor_desc * this, thread_desc * owner ) { |
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338 | //Pass the monitor appropriately |
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339 | this->owner = owner; |
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340 | |
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341 | //We are passing the monitor to someone else, which means recursion level is not 0 |
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342 | this->recursion = owner ? 1 : 0; |
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343 | } |
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344 | |
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345 | static inline thread_desc * next_thread( monitor_desc * this ) { |
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346 | //Check the signaller stack |
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347 | __condition_criterion_t * urgent = pop( &this->signal_stack ); |
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348 | if( urgent ) { |
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349 | //The signaller stack is not empty, |
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350 | //regardless of if we are ready to baton pass, |
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351 | //we need to set the monitor as in use |
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352 | set_owner( this, urgent->owner->waiting_thread ); |
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353 | |
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354 | return check_condition( urgent ); |
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355 | } |
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356 | |
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357 | // No signaller thread |
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358 | // Get the next thread in the entry_queue |
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359 | thread_desc * new_owner = pop_head( &this->entry_queue ); |
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360 | set_owner( this, new_owner ); |
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361 | |
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362 | return new_owner; |
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363 | } |
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364 | |
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365 | static inline void lock_all( spinlock ** locks, unsigned short count ) { |
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366 | for( int i = 0; i < count; i++ ) { |
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367 | lock( locks[i] ); |
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368 | } |
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369 | } |
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370 | |
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371 | static inline void lock_all( monitor_desc ** source, spinlock ** /*out*/ locks, unsigned short count ) { |
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372 | for( int i = 0; i < count; i++ ) { |
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373 | spinlock * l = &source[i]->lock; |
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374 | lock( l ); |
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375 | if(locks) locks[i] = l; |
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376 | } |
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377 | } |
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378 | |
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379 | static inline void unlock_all( spinlock ** locks, unsigned short count ) { |
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380 | for( int i = 0; i < count; i++ ) { |
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381 | unlock( locks[i] ); |
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382 | } |
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383 | } |
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384 | |
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385 | static inline void unlock_all( monitor_desc ** locks, unsigned short count ) { |
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386 | for( int i = 0; i < count; i++ ) { |
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387 | unlock( &locks[i]->lock ); |
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388 | } |
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389 | } |
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390 | |
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391 | |
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392 | static inline void save_recursion ( monitor_desc ** ctx, unsigned int * /*out*/ recursions, unsigned short count ) { |
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393 | for( int i = 0; i < count; i++ ) { |
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394 | recursions[i] = ctx[i]->recursion; |
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395 | } |
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396 | } |
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397 | |
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398 | static inline void restore_recursion( monitor_desc ** ctx, unsigned int * /*in */ recursions, unsigned short count ) { |
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399 | for( int i = 0; i < count; i++ ) { |
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400 | ctx[i]->recursion = recursions[i]; |
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401 | } |
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402 | } |
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403 | |
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404 | // Function has 2 different behavior |
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405 | // 1 - Marks a monitors as being ready to run |
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406 | // 2 - Checks if all the monitors are ready to run |
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407 | // if so return the thread to run |
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408 | static inline thread_desc * check_condition( __condition_criterion_t * target ) { |
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409 | __condition_node_t * node = target->owner; |
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410 | unsigned short count = node->count; |
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411 | __condition_criterion_t * criteria = node->criteria; |
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412 | |
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413 | bool ready2run = true; |
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414 | |
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415 | for( int i = 0; i < count; i++ ) { |
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416 | |
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417 | LIB_DEBUG_PRINT_SAFE( "Checking %p for %p\n", &criteria[i], target ); |
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418 | if( &criteria[i] == target ) { |
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419 | criteria[i].ready = true; |
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420 | LIB_DEBUG_PRINT_SAFE( "True\n" ); |
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421 | } |
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422 | |
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423 | ready2run = criteria[i].ready && ready2run; |
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424 | } |
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425 | |
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426 | LIB_DEBUG_PRINT_SAFE( "Runing %i\n", ready2run ); |
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427 | return ready2run ? node->waiting_thread : NULL; |
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428 | } |
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429 | |
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430 | static inline void brand_condition( condition * this ) { |
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431 | thread_desc * thrd = this_thread(); |
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432 | if( !this->monitors ) { |
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433 | LIB_DEBUG_PRINT_SAFE("Branding\n"); |
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434 | assertf( thrd->current_monitors != NULL, "No current monitor to brand condition", thrd->current_monitors ); |
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435 | this->monitor_count = thrd->current_monitor_count; |
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436 | |
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437 | this->monitors = malloc( this->monitor_count * sizeof( *this->monitors ) ); |
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438 | for( int i = 0; i < this->monitor_count; i++ ) { |
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439 | this->monitors[i] = thrd->current_monitors[i]; |
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440 | } |
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441 | } |
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442 | } |
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443 | |
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444 | static inline unsigned short insert_unique( thread_desc ** thrds, unsigned short end, thread_desc * val ) { |
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445 | if( !val ) return end; |
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446 | |
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447 | for(int i = 0; i <= end; i++) { |
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448 | if( thrds[i] == val ) return end; |
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449 | } |
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450 | |
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451 | thrds[end] = val; |
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452 | return end + 1; |
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453 | } |
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454 | |
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455 | void ?{}( __condition_blocked_queue_t * this ) { |
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456 | this->head = NULL; |
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457 | this->tail = &this->head; |
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458 | } |
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459 | |
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460 | void append( __condition_blocked_queue_t * this, __condition_node_t * c ) { |
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461 | assert(this->tail != NULL); |
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462 | *this->tail = c; |
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463 | this->tail = &c->next; |
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464 | } |
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465 | |
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466 | __condition_node_t * pop_head( __condition_blocked_queue_t * this ) { |
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467 | __condition_node_t * head = this->head; |
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468 | if( head ) { |
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469 | this->head = head->next; |
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470 | if( !head->next ) { |
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471 | this->tail = &this->head; |
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472 | } |
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473 | head->next = NULL; |
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474 | } |
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475 | return head; |
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476 | } |
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