1 | // |
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2 | // Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo |
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3 | // |
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4 | // The contents of this file are covered under the licence agreement in the |
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5 | // file "LICENCE" distributed with Cforall. |
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6 | // |
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7 | // coroutine -- |
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8 | // |
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9 | // Author : Thierry Delisle |
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10 | // Created On : Mon Nov 28 12:27:26 2016 |
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11 | // Last Modified By : Peter A. Buhr |
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12 | // Last Modified On : Tue Feb 4 12:29:26 2020 |
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13 | // Update Count : 11 |
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14 | // |
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15 | |
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16 | #pragma once |
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17 | |
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18 | #include <assert.h> |
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19 | #include "invoke.h" |
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20 | #include "../exception.hfa" |
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21 | |
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22 | //----------------------------------------------------------------------------- |
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23 | // Exception thrown from resume when a coroutine stack is cancelled. |
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24 | EHM_FORALL_EXCEPTION(CoroutineCancelled, (coroutine_t &), (coroutine_t)) ( |
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25 | coroutine_t * the_coroutine; |
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26 | exception_t * the_exception; |
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27 | ); |
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28 | |
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29 | forall(T &) |
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30 | void copy(CoroutineCancelled(T) * dst, CoroutineCancelled(T) * src); |
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31 | |
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32 | forall(T &) |
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33 | const char * msg(CoroutineCancelled(T) *); |
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34 | |
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35 | //----------------------------------------------------------------------------- |
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36 | // Coroutine trait |
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37 | // Anything that implements this trait can be resumed. |
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38 | // Anything that is resumed is a coroutine. |
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39 | trait is_coroutine(T & | IS_RESUMPTION_EXCEPTION(CoroutineCancelled, (T))) { |
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40 | void main(T & this); |
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41 | $coroutine * get_coroutine(T & this); |
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42 | }; |
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43 | |
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44 | #define DECL_COROUTINE(X) static inline $coroutine* get_coroutine(X& this) { return &this.__cor; } void main(X& this) |
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45 | |
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46 | //----------------------------------------------------------------------------- |
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47 | // Ctors and dtors |
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48 | // void ?{}( coStack_t & this ); |
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49 | // void ^?{}( coStack_t & this ); |
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50 | |
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51 | void ?{}( $coroutine & this, const char name[], void * storage, size_t storageSize ); |
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52 | void ^?{}( $coroutine & this ); |
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53 | |
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54 | static inline void ?{}( $coroutine & this) { this{ "Anonymous Coroutine", 0p, 0 }; } |
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55 | static inline void ?{}( $coroutine & this, size_t stackSize) { this{ "Anonymous Coroutine", 0p, stackSize }; } |
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56 | static inline void ?{}( $coroutine & this, void * storage, size_t storageSize ) { this{ "Anonymous Coroutine", storage, storageSize }; } |
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57 | static inline void ?{}( $coroutine & this, const char name[]) { this{ name, 0p, 0 }; } |
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58 | static inline void ?{}( $coroutine & this, const char name[], size_t stackSize ) { this{ name, 0p, stackSize }; } |
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59 | |
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60 | //----------------------------------------------------------------------------- |
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61 | // Public coroutine API |
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62 | forall(T & | is_coroutine(T) | { EHM_DEFAULT_VTABLE(CoroutineCancelled, (T)); }) |
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63 | void prime(T & cor); |
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64 | |
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65 | static inline struct $coroutine * active_coroutine() { return active_thread()->curr_cor; } |
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66 | |
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67 | //----------------------------------------------------------------------------- |
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68 | // PRIVATE exposed because of inline |
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69 | |
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70 | // Start coroutine routines |
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71 | extern "C" { |
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72 | void __cfactx_invoke_coroutine(void (*main)(void *), void * this); |
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73 | |
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74 | forall(T &) |
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75 | void __cfactx_start(void (*main)(T &), struct $coroutine * cor, T & this, void (*invoke)(void (*main)(void *), void *)); |
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76 | |
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77 | extern void __cfactx_coroutine_unwind(struct _Unwind_Exception * storage, struct $coroutine *) __attribute__ ((__noreturn__)); |
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78 | |
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79 | extern void __cfactx_switch( struct __stack_context_t * from, struct __stack_context_t * to ) asm ("__cfactx_switch"); |
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80 | } |
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81 | |
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82 | // Private wrappers for context switch and stack creation |
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83 | // Wrapper for co |
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84 | static inline void $ctx_switch( $coroutine * src, $coroutine * dst ) __attribute__((nonnull (1, 2))) { |
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85 | // set state of current coroutine to inactive |
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86 | src->state = src->state == Halted ? Halted : Blocked; |
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87 | |
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88 | // get the active thread once |
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89 | $thread * athrd = active_thread(); |
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90 | |
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91 | // Mark the coroutine |
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92 | /* paranoid */ verify( !athrd->corctx_flag ); |
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93 | athrd->corctx_flag = true; |
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94 | |
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95 | // set new coroutine that task is executing |
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96 | athrd->curr_cor = dst; |
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97 | |
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98 | // context switch to specified coroutine |
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99 | /* paranoid */ verify( dst->context.SP ); |
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100 | __cfactx_switch( &src->context, &dst->context ); |
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101 | // when __cfactx_switch returns we are back in the src coroutine |
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102 | |
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103 | /* paranoid */ verify( athrd->corctx_flag ); |
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104 | athrd->corctx_flag = false; |
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105 | |
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106 | // set state of new coroutine to active |
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107 | src->state = Active; |
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108 | |
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109 | if( unlikely(src->cancellation != 0p) ) { |
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110 | __cfactx_coroutine_unwind(src->cancellation, src); |
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111 | } |
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112 | } |
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113 | |
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114 | extern void __stack_prepare( __stack_info_t * this, size_t size /* ignored if storage already allocated */); |
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115 | extern void __stack_clean ( __stack_info_t * this ); |
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116 | |
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117 | |
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118 | // Suspend implementation inlined for performance |
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119 | extern "C" { |
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120 | static inline void __cfactx_suspend(void) { |
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121 | // optimization : read TLS once and reuse it |
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122 | // Safety note: this is preemption safe since if |
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123 | // preemption occurs after this line, the pointer |
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124 | // will also migrate which means this value will |
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125 | // stay in syn with the TLS |
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126 | $coroutine * src = active_coroutine(); |
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127 | |
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128 | assertf( src->last != 0, |
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129 | "Attempt to suspend coroutine \"%.256s\" (%p) that has never been resumed.\n" |
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130 | "Possible cause is a suspend executed in a member called by a coroutine user rather than by the coroutine main.", |
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131 | src->name, src ); |
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132 | assertf( src->last->state != Halted, |
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133 | "Attempt by coroutine \"%.256s\" (%p) to suspend back to terminated coroutine \"%.256s\" (%p).\n" |
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134 | "Possible cause is terminated coroutine's main routine has already returned.", |
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135 | src->name, src, src->last->name, src->last ); |
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136 | |
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137 | $ctx_switch( src, src->last ); |
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138 | } |
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139 | } |
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140 | |
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141 | forall(T & | is_coroutine(T)) |
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142 | void __cfaehm_cancelled_coroutine( |
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143 | T & cor, $coroutine * desc, EHM_DEFAULT_VTABLE(CoroutineCancelled, (T)) ); |
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144 | |
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145 | // Resume implementation inlined for performance |
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146 | forall(T & | is_coroutine(T) | { EHM_DEFAULT_VTABLE(CoroutineCancelled, (T)); }) |
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147 | static inline T & resume(T & cor) { |
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148 | // optimization : read TLS once and reuse it |
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149 | // Safety note: this is preemption safe since if |
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150 | // preemption occurs after this line, the pointer |
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151 | // will also migrate which means this value will |
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152 | // stay in syn with the TLS |
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153 | $coroutine * src = active_coroutine(); |
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154 | $coroutine * dst = get_coroutine(cor); |
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155 | |
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156 | if( unlikely(dst->context.SP == 0p) ) { |
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157 | __stack_prepare(&dst->stack, 65000); |
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158 | __cfactx_start(main, dst, cor, __cfactx_invoke_coroutine); |
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159 | } |
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160 | |
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161 | // not resuming self ? |
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162 | if ( src != dst ) { |
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163 | assertf( dst->state != Halted , |
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164 | "Attempt by coroutine %.256s (%p) to resume terminated coroutine %.256s (%p).\n" |
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165 | "Possible cause is terminated coroutine's main routine has already returned.", |
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166 | src->name, src, dst->name, dst ); |
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167 | |
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168 | // set last resumer |
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169 | dst->last = src; |
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170 | dst->starter = dst->starter ? dst->starter : src; |
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171 | } |
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172 | |
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173 | // always done for performance testing |
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174 | $ctx_switch( src, dst ); |
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175 | if ( unlikely(dst->cancellation) ) { |
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176 | __cfaehm_cancelled_coroutine( cor, dst, _default_vtable ); |
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177 | } |
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178 | |
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179 | return cor; |
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180 | } |
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181 | |
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182 | static inline void resume( $coroutine * dst ) __attribute__((nonnull (1))) { |
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183 | // optimization : read TLS once and reuse it |
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184 | // Safety note: this is preemption safe since if |
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185 | // preemption occurs after this line, the pointer |
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186 | // will also migrate which means this value will |
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187 | // stay in syn with the TLS |
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188 | $coroutine * src = active_coroutine(); |
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189 | |
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190 | // not resuming self ? |
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191 | if ( src != dst ) { |
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192 | assertf( dst->state != Halted , |
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193 | "Attempt by coroutine %.256s (%p) to resume terminated coroutine %.256s (%p).\n" |
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194 | "Possible cause is terminated coroutine's main routine has already returned.", |
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195 | src->name, src, dst->name, dst ); |
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196 | |
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197 | // set last resumer |
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198 | dst->last = src; |
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199 | } |
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200 | |
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201 | // always done for performance testing |
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202 | $ctx_switch( src, dst ); |
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203 | } |
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204 | |
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205 | // Local Variables: // |
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206 | // mode: c // |
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207 | // tab-width: 4 // |
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208 | // End: // |
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