[ab1b971] | 1 | // |
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| 2 | // Cforall Version 1.0.0 Copyright (C) 2021 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 | // locks.hfa -- LIBCFATHREAD |
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| 8 | // Runtime locks that used with the runtime thread system. |
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| 9 | // |
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| 10 | // Author : Colby Alexander Parsons |
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| 11 | // Created On : Thu Jan 21 19:46:50 2021 |
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| 12 | // Last Modified By : |
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| 13 | // Last Modified On : |
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| 14 | // Update Count : |
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| 15 | // |
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| 16 | |
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| 17 | #define __cforall_thread__ |
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[43784ac] | 18 | #define _GNU_SOURCE |
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[ab1b971] | 19 | |
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[848439f] | 20 | #include "locks.hfa" |
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[708ae38] | 21 | #include "kernel/private.hfa" |
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[848439f] | 22 | |
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| 23 | #include <kernel.hfa> |
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| 24 | #include <stdlib.hfa> |
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| 25 | |
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[ac5816d] | 26 | //----------------------------------------------------------------------------- |
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| 27 | // info_thread |
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[fd54fef] | 28 | forall(L & | is_blocking_lock(L)) { |
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[ac5816d] | 29 | struct info_thread { |
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[82f4063] | 30 | // used to put info_thread on a dl queue |
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| 31 | inline dlink(info_thread(L)); |
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[ac5816d] | 32 | |
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| 33 | // waiting thread |
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[e84ab3d] | 34 | struct thread$ * t; |
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[ac5816d] | 35 | |
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| 36 | // shadow field |
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| 37 | uintptr_t info; |
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| 38 | |
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| 39 | // lock that is passed to wait() (if one is passed) |
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| 40 | L * lock; |
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| 41 | |
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| 42 | // true when signalled and false when timeout wakes thread |
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| 43 | bool signalled; |
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| 44 | }; |
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[82f4063] | 45 | P9_EMBEDDED( info_thread(L), dlink(info_thread(L)) ) |
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[848439f] | 46 | |
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[e84ab3d] | 47 | void ?{}( info_thread(L) & this, thread$ * t, uintptr_t info, L * l ) { |
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[848439f] | 48 | this.t = t; |
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| 49 | this.info = info; |
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[ac5816d] | 50 | this.lock = l; |
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[848439f] | 51 | } |
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| 52 | |
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[ac5816d] | 53 | void ^?{}( info_thread(L) & this ) {} |
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[848439f] | 54 | } |
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[cad1df1] | 55 | |
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[ac5816d] | 56 | //----------------------------------------------------------------------------- |
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| 57 | // Blocking Locks |
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[848439f] | 58 | void ?{}( blocking_lock & this, bool multi_acquisition, bool strict_owner ) { |
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| 59 | this.lock{}; |
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| 60 | this.blocked_threads{}; |
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| 61 | this.wait_count = 0; |
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| 62 | this.multi_acquisition = multi_acquisition; |
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| 63 | this.strict_owner = strict_owner; |
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| 64 | this.owner = 0p; |
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| 65 | this.recursion_count = 0; |
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| 66 | } |
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| 67 | |
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[cad1df1] | 68 | void ^?{}( blocking_lock & this ) {} |
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[ab1b971] | 69 | |
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[848439f] | 70 | |
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| 71 | void lock( blocking_lock & this ) with( this ) { |
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| 72 | lock( lock __cfaabi_dbg_ctx2 ); |
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[e84ab3d] | 73 | thread$ * thrd = active_thread(); |
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[ac5816d] | 74 | |
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| 75 | // single acquisition lock is held by current thread |
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| 76 | /* paranoid */ verifyf( owner != thrd || multi_acquisition, "Single acquisition lock holder (%p) attempted to reacquire the lock %p resulting in a deadlock.", owner, &this ); |
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| 77 | |
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| 78 | // lock is held by some other thread |
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| 79 | if ( owner != 0p && owner != thrd ) { |
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[82f4063] | 80 | insert_last( blocked_threads, *thrd ); |
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[848439f] | 81 | wait_count++; |
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| 82 | unlock( lock ); |
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[eeb5023] | 83 | park( ); |
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[ac5816d] | 84 | } |
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| 85 | // multi acquisition lock is held by current thread |
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| 86 | else if ( owner == thrd && multi_acquisition ) { |
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[848439f] | 87 | recursion_count++; |
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| 88 | unlock( lock ); |
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[ac5816d] | 89 | } |
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| 90 | // lock isn't held |
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| 91 | else { |
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| 92 | owner = thrd; |
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[848439f] | 93 | recursion_count = 1; |
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| 94 | unlock( lock ); |
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| 95 | } |
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| 96 | } |
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| 97 | |
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| 98 | bool try_lock( blocking_lock & this ) with( this ) { |
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| 99 | bool ret = false; |
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| 100 | lock( lock __cfaabi_dbg_ctx2 ); |
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[ac5816d] | 101 | |
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| 102 | // lock isn't held |
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| 103 | if ( owner == 0p ) { |
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[6a8882c] | 104 | owner = active_thread(); |
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| 105 | recursion_count = 1; |
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[848439f] | 106 | ret = true; |
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[ac5816d] | 107 | } |
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| 108 | // multi acquisition lock is held by current thread |
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| 109 | else if ( owner == active_thread() && multi_acquisition ) { |
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[848439f] | 110 | recursion_count++; |
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| 111 | ret = true; |
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| 112 | } |
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[ac5816d] | 113 | |
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[848439f] | 114 | unlock( lock ); |
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| 115 | return ret; |
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| 116 | } |
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| 117 | |
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[cad1df1] | 118 | void pop_and_set_new_owner( blocking_lock & this ) with( this ) { |
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[e84ab3d] | 119 | thread$ * t = &try_pop_front( blocked_threads ); |
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[cad1df1] | 120 | owner = t; |
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| 121 | recursion_count = ( t ? 1 : 0 ); |
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[f9b68d6] | 122 | if ( t ) wait_count--; |
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[cad1df1] | 123 | unpark( t ); |
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| 124 | } |
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| 125 | |
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| 126 | void unlock( blocking_lock & this ) with( this ) { |
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| 127 | lock( lock __cfaabi_dbg_ctx2 ); |
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[ac5816d] | 128 | /* paranoid */ verifyf( owner != 0p, "Attempt to release lock %p that isn't held", &this ); |
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[22b7579] | 129 | /* paranoid */ verifyf( owner == active_thread() || !strict_owner , "Thread %p other than the owner %p attempted to release owner lock %p", owner, active_thread(), &this ); |
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| 130 | /* paranoid */ verifyf( recursion_count == 1 || multi_acquisition, "Thread %p attempted to release owner lock %p which is not recursive but has a recursive count of %zu", active_thread(), &this, recursion_count ); |
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[ac5816d] | 131 | |
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| 132 | // if recursion count is zero release lock and set new owner if one is waiting |
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[848439f] | 133 | recursion_count--; |
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[ac5816d] | 134 | if ( recursion_count == 0 ) { |
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[cad1df1] | 135 | pop_and_set_new_owner( this ); |
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[848439f] | 136 | } |
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| 137 | unlock( lock ); |
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| 138 | } |
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| 139 | |
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| 140 | size_t wait_count( blocking_lock & this ) with( this ) { |
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| 141 | return wait_count; |
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| 142 | } |
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| 143 | |
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[e84ab3d] | 144 | void on_notify( blocking_lock & this, thread$ * t ) with( this ) { |
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[ac5816d] | 145 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 146 | // lock held |
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| 147 | if ( owner != 0p ) { |
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[82f4063] | 148 | insert_last( blocked_threads, *t ); |
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[848439f] | 149 | wait_count++; |
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| 150 | unlock( lock ); |
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[ac5816d] | 151 | } |
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| 152 | // lock not held |
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| 153 | else { |
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[848439f] | 154 | owner = t; |
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[6a8882c] | 155 | recursion_count = 1; |
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[eeb5023] | 156 | unpark( t ); |
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[848439f] | 157 | unlock( lock ); |
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| 158 | } |
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| 159 | } |
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| 160 | |
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[22b7579] | 161 | size_t on_wait( blocking_lock & this ) with( this ) { |
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[ac5816d] | 162 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 163 | /* paranoid */ verifyf( owner != 0p, "Attempt to release lock %p that isn't held", &this ); |
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| 164 | /* paranoid */ verifyf( owner == active_thread() || !strict_owner, "Thread %p other than the owner %p attempted to release owner lock %p", owner, active_thread(), &this ); |
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| 165 | |
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[22b7579] | 166 | size_t ret = recursion_count; |
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| 167 | |
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[cad1df1] | 168 | pop_and_set_new_owner( this ); |
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[848439f] | 169 | unlock( lock ); |
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[22b7579] | 170 | return ret; |
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| 171 | } |
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| 172 | |
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| 173 | void on_wakeup( blocking_lock & this, size_t recursion ) with( this ) { |
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| 174 | recursion_count = recursion; |
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[848439f] | 175 | } |
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| 176 | |
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[ac5816d] | 177 | //----------------------------------------------------------------------------- |
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| 178 | // alarm node wrapper |
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[fd54fef] | 179 | forall(L & | is_blocking_lock(L)) { |
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[c20533ea] | 180 | struct alarm_node_wrap { |
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| 181 | alarm_node_t alarm_node; |
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| 182 | condition_variable(L) * cond; |
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[90a10e8] | 183 | info_thread(L) * info_thd; |
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[c20533ea] | 184 | }; |
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| 185 | |
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[c457dc41] | 186 | void ?{}( alarm_node_wrap(L) & this, Duration alarm, Duration period, Alarm_Callback callback, condition_variable(L) * c, info_thread(L) * i ) { |
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[c20533ea] | 187 | this.alarm_node{ callback, alarm, period }; |
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[ac5816d] | 188 | this.cond = c; |
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[90a10e8] | 189 | this.info_thd = i; |
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[c20533ea] | 190 | } |
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| 191 | |
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| 192 | void ^?{}( alarm_node_wrap(L) & this ) { } |
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[848439f] | 193 | |
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[c5bbb9b] | 194 | void timeout_handler ( alarm_node_wrap(L) & this ) with( this ) { |
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[ac5816d] | 195 | // This condition_variable member is called from the kernel, and therefore, cannot block, but it can spin. |
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| 196 | lock( cond->lock __cfaabi_dbg_ctx2 ); |
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| 197 | |
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| 198 | // this check is necessary to avoid a race condition since this timeout handler |
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| 199 | // may still be called after a thread has been removed from the queue but |
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| 200 | // before the alarm is unregistered |
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[82f4063] | 201 | if ( (*info_thd)`isListed ) { // is thread on queue |
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[90a10e8] | 202 | info_thd->signalled = false; |
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[ac5816d] | 203 | // remove this thread O(1) |
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[82f4063] | 204 | remove( *info_thd ); |
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[6a8882c] | 205 | cond->count--; |
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[90a10e8] | 206 | if( info_thd->lock ) { |
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[ac5816d] | 207 | // call lock's on_notify if a lock was passed |
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[90a10e8] | 208 | on_notify(*info_thd->lock, info_thd->t); |
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[ac5816d] | 209 | } else { |
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| 210 | // otherwise wake thread |
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[90a10e8] | 211 | unpark( info_thd->t ); |
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[ac5816d] | 212 | } |
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| 213 | } |
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| 214 | unlock( cond->lock ); |
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[848439f] | 215 | } |
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| 216 | |
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[797a193] | 217 | // this casts the alarm node to our wrapped type since we used type erasure |
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[cad1df1] | 218 | void alarm_node_wrap_cast( alarm_node_t & a ) { timeout_handler( (alarm_node_wrap(L) &)a ); } |
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[c20533ea] | 219 | } |
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| 220 | |
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[ac5816d] | 221 | //----------------------------------------------------------------------------- |
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[7f958c4] | 222 | // Synchronization Locks |
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[fd54fef] | 223 | forall(L & | is_blocking_lock(L)) { |
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[c20533ea] | 224 | |
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[7f958c4] | 225 | //----------------------------------------------------------------------------- |
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| 226 | // condition variable |
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[848439f] | 227 | void ?{}( condition_variable(L) & this ){ |
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[eeb5023] | 228 | this.lock{}; |
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| 229 | this.blocked_threads{}; |
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| 230 | this.count = 0; |
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[848439f] | 231 | } |
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| 232 | |
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[cad1df1] | 233 | void ^?{}( condition_variable(L) & this ){ } |
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[848439f] | 234 | |
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[cad1df1] | 235 | void process_popped( condition_variable(L) & this, info_thread(L) & popped ) with( this ) { |
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| 236 | if(&popped != 0p) { |
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[dff1fd1] | 237 | popped.signalled = true; |
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[eeb5023] | 238 | count--; |
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[cad1df1] | 239 | if (popped.lock) { |
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[ac5816d] | 240 | // if lock passed call on_notify |
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| 241 | on_notify(*popped.lock, popped.t); |
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[848439f] | 242 | } else { |
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[ac5816d] | 243 | // otherwise wake thread |
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| 244 | unpark(popped.t); |
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[848439f] | 245 | } |
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| 246 | } |
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[cad1df1] | 247 | } |
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| 248 | |
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| 249 | bool notify_one( condition_variable(L) & this ) with( this ) { |
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| 250 | lock( lock __cfaabi_dbg_ctx2 ); |
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[82f4063] | 251 | bool ret = ! blocked_threads`isEmpty; |
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| 252 | process_popped(this, try_pop_front( blocked_threads )); |
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[848439f] | 253 | unlock( lock ); |
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| 254 | return ret; |
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| 255 | } |
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| 256 | |
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[eeb5023] | 257 | bool notify_all( condition_variable(L) & this ) with(this) { |
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[848439f] | 258 | lock( lock __cfaabi_dbg_ctx2 ); |
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[82f4063] | 259 | bool ret = ! blocked_threads`isEmpty; |
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| 260 | while( ! blocked_threads`isEmpty ) { |
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| 261 | process_popped(this, try_pop_front( blocked_threads )); |
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[848439f] | 262 | } |
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| 263 | unlock( lock ); |
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| 264 | return ret; |
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| 265 | } |
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| 266 | |
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[eeb5023] | 267 | uintptr_t front( condition_variable(L) & this ) with(this) { |
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[82f4063] | 268 | return blocked_threads`isEmpty ? NULL : blocked_threads`first.info; |
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[848439f] | 269 | } |
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| 270 | |
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[22b7579] | 271 | bool empty( condition_variable(L) & this ) with(this) { |
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| 272 | lock( lock __cfaabi_dbg_ctx2 ); |
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[82f4063] | 273 | bool ret = blocked_threads`isEmpty; |
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[22b7579] | 274 | unlock( lock ); |
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| 275 | return ret; |
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| 276 | } |
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[cad1df1] | 277 | |
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| 278 | int counter( condition_variable(L) & this ) with(this) { return count; } |
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[848439f] | 279 | |
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[cad1df1] | 280 | size_t queue_and_get_recursion( condition_variable(L) & this, info_thread(L) * i ) with(this) { |
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[ac5816d] | 281 | // add info_thread to waiting queue |
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[82f4063] | 282 | insert_last( blocked_threads, *i ); |
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[cad1df1] | 283 | count++; |
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| 284 | size_t recursion_count = 0; |
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[ac5816d] | 285 | if (i->lock) { |
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| 286 | // if lock was passed get recursion count to reset to after waking thread |
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[22b7579] | 287 | recursion_count = on_wait( *i->lock ); |
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[cad1df1] | 288 | } |
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| 289 | return recursion_count; |
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[848439f] | 290 | } |
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| 291 | |
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[cad1df1] | 292 | // helper for wait()'s' with no timeout |
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[eeb5023] | 293 | void queue_info_thread( condition_variable(L) & this, info_thread(L) & i ) with(this) { |
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[848439f] | 294 | lock( lock __cfaabi_dbg_ctx2 ); |
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[cad1df1] | 295 | size_t recursion_count = queue_and_get_recursion(this, &i); |
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[848439f] | 296 | unlock( lock ); |
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[ac5816d] | 297 | |
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| 298 | // blocks here |
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| 299 | park( ); |
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| 300 | |
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| 301 | // resets recursion count here after waking |
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[22b7579] | 302 | if (i.lock) on_wakeup(*i.lock, recursion_count); |
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[848439f] | 303 | } |
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| 304 | |
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[ac5816d] | 305 | #define WAIT( u, l ) \ |
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| 306 | info_thread( L ) i = { active_thread(), u, l }; \ |
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| 307 | queue_info_thread( this, i ); |
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| 308 | |
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[eeb5023] | 309 | // helper for wait()'s' with a timeout |
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[afd7faf] | 310 | void queue_info_thread_timeout( condition_variable(L) & this, info_thread(L) & info, Duration t, Alarm_Callback callback ) with(this) { |
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[eeb5023] | 311 | lock( lock __cfaabi_dbg_ctx2 ); |
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[cad1df1] | 312 | size_t recursion_count = queue_and_get_recursion(this, &info); |
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[afd7faf] | 313 | alarm_node_wrap(L) node_wrap = { t, 0`s, callback, &this, &info }; |
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[eeb5023] | 314 | register_self( &node_wrap.alarm_node ); |
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[848439f] | 315 | unlock( lock ); |
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| 316 | |
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[ac5816d] | 317 | // blocks here |
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| 318 | park(); |
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[848439f] | 319 | |
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[ac5816d] | 320 | // unregisters alarm so it doesn't go off if this happens first |
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| 321 | unregister_self( &node_wrap.alarm_node ); |
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[848439f] | 322 | |
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[ac5816d] | 323 | // resets recursion count here after waking |
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[22b7579] | 324 | if (info.lock) on_wakeup(*info.lock, recursion_count); |
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[848439f] | 325 | } |
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| 326 | |
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[ac5816d] | 327 | #define WAIT_TIME( u, l, t ) \ |
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| 328 | info_thread( L ) i = { active_thread(), u, l }; \ |
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[afd7faf] | 329 | queue_info_thread_timeout(this, i, t, alarm_node_wrap_cast ); \ |
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[dff1fd1] | 330 | return i.signalled; |
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[848439f] | 331 | |
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[ac5816d] | 332 | void wait( condition_variable(L) & this ) with(this) { WAIT( 0, 0p ) } |
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| 333 | void wait( condition_variable(L) & this, uintptr_t info ) with(this) { WAIT( info, 0p ) } |
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| 334 | void wait( condition_variable(L) & this, L & l ) with(this) { WAIT( 0, &l ) } |
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| 335 | void wait( condition_variable(L) & this, L & l, uintptr_t info ) with(this) { WAIT( info, &l ) } |
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| 336 | |
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[c457dc41] | 337 | bool wait( condition_variable(L) & this, Duration duration ) with(this) { WAIT_TIME( 0 , 0p , duration ) } |
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| 338 | bool wait( condition_variable(L) & this, uintptr_t info, Duration duration ) with(this) { WAIT_TIME( info, 0p , duration ) } |
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| 339 | bool wait( condition_variable(L) & this, L & l, Duration duration ) with(this) { WAIT_TIME( 0 , &l , duration ) } |
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| 340 | bool wait( condition_variable(L) & this, L & l, uintptr_t info, Duration duration ) with(this) { WAIT_TIME( info, &l , duration ) } |
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[7f958c4] | 341 | |
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| 342 | //----------------------------------------------------------------------------- |
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| 343 | // fast_cond_var |
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| 344 | void ?{}( fast_cond_var(L) & this ){ |
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| 345 | this.blocked_threads{}; |
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| 346 | #ifdef __CFA_DEBUG__ |
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| 347 | this.lock_used = 0p; |
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| 348 | #endif |
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| 349 | } |
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| 350 | void ^?{}( fast_cond_var(L) & this ){ } |
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| 351 | |
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| 352 | bool notify_one( fast_cond_var(L) & this ) with(this) { |
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| 353 | bool ret = ! blocked_threads`isEmpty; |
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| 354 | if ( ret ) { |
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| 355 | info_thread(L) & popped = try_pop_front( blocked_threads ); |
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| 356 | on_notify(*popped.lock, popped.t); |
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| 357 | } |
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| 358 | return ret; |
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| 359 | } |
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| 360 | bool notify_all( fast_cond_var(L) & this ) with(this) { |
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| 361 | bool ret = ! blocked_threads`isEmpty; |
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| 362 | while( ! blocked_threads`isEmpty ) { |
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| 363 | info_thread(L) & popped = try_pop_front( blocked_threads ); |
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| 364 | on_notify(*popped.lock, popped.t); |
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| 365 | } |
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| 366 | return ret; |
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| 367 | } |
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| 368 | |
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| 369 | uintptr_t front( fast_cond_var(L) & this ) with(this) { return blocked_threads`isEmpty ? NULL : blocked_threads`first.info; } |
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| 370 | bool empty ( fast_cond_var(L) & this ) with(this) { return blocked_threads`isEmpty; } |
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| 371 | |
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| 372 | void wait( fast_cond_var(L) & this, L & l ) { |
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| 373 | wait( this, l, 0 ); |
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| 374 | } |
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| 375 | |
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| 376 | void wait( fast_cond_var(L) & this, L & l, uintptr_t info ) with(this) { |
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| 377 | // brand cond lock with lock |
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| 378 | #ifdef __CFA_DEBUG__ |
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| 379 | if ( lock_used == 0p ) lock_used = &l; |
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| 380 | else { assert(lock_used == &l); } |
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| 381 | #endif |
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| 382 | info_thread( L ) i = { active_thread(), info, &l }; |
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| 383 | insert_last( blocked_threads, i ); |
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| 384 | size_t recursion_count = on_wait( *i.lock ); |
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| 385 | park( ); |
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| 386 | on_wakeup(*i.lock, recursion_count); |
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| 387 | } |
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[848439f] | 388 | } |
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[454f478] | 389 | |
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| 390 | //----------------------------------------------------------------------------- |
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| 391 | // Semaphore |
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| 392 | void ?{}( semaphore & this, int count = 1 ) { |
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| 393 | (this.lock){}; |
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| 394 | this.count = count; |
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| 395 | (this.waiting){}; |
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| 396 | } |
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| 397 | void ^?{}(semaphore & this) {} |
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| 398 | |
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| 399 | bool P(semaphore & this) with( this ){ |
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| 400 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 401 | count -= 1; |
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| 402 | if ( count < 0 ) { |
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| 403 | // queue current task |
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| 404 | append( waiting, active_thread() ); |
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| 405 | |
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| 406 | // atomically release spin lock and block |
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| 407 | unlock( lock ); |
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| 408 | park(); |
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| 409 | return true; |
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| 410 | } |
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| 411 | else { |
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| 412 | unlock( lock ); |
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| 413 | return false; |
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| 414 | } |
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| 415 | } |
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| 416 | |
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[e84ab3d] | 417 | thread$ * V (semaphore & this, const bool doUnpark ) with( this ) { |
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| 418 | thread$ * thrd = 0p; |
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[454f478] | 419 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 420 | count += 1; |
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| 421 | if ( count <= 0 ) { |
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| 422 | // remove task at head of waiting list |
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| 423 | thrd = pop_head( waiting ); |
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| 424 | } |
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| 425 | |
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| 426 | unlock( lock ); |
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| 427 | |
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| 428 | // make new owner |
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[22b7579] | 429 | if( doUnpark ) unpark( thrd ); |
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| 430 | |
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| 431 | return thrd; |
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| 432 | } |
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[454f478] | 433 | |
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[22b7579] | 434 | bool V(semaphore & this) with( this ) { |
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[e84ab3d] | 435 | thread$ * thrd = V(this, true); |
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[454f478] | 436 | return thrd != 0p; |
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| 437 | } |
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| 438 | |
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| 439 | bool V(semaphore & this, unsigned diff) with( this ) { |
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[e84ab3d] | 440 | thread$ * thrd = 0p; |
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[454f478] | 441 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 442 | int release = max(-count, (int)diff); |
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| 443 | count += diff; |
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| 444 | for(release) { |
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| 445 | unpark( pop_head( waiting ) ); |
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| 446 | } |
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| 447 | |
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| 448 | unlock( lock ); |
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| 449 | |
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| 450 | return thrd != 0p; |
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| 451 | } |
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