[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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[c18bf9e] | 26 | #pragma GCC visibility push(default) |
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| 27 | |
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[ac5816d] | 28 | //----------------------------------------------------------------------------- |
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| 29 | // info_thread |
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[fd54fef] | 30 | forall(L & | is_blocking_lock(L)) { |
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[ac5816d] | 31 | struct info_thread { |
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[82f4063] | 32 | // used to put info_thread on a dl queue |
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| 33 | inline dlink(info_thread(L)); |
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[ac5816d] | 34 | |
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| 35 | // waiting thread |
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[e84ab3d] | 36 | struct thread$ * t; |
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[ac5816d] | 37 | |
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| 38 | // shadow field |
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| 39 | uintptr_t info; |
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| 40 | |
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| 41 | // lock that is passed to wait() (if one is passed) |
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| 42 | L * lock; |
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| 43 | |
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| 44 | // true when signalled and false when timeout wakes thread |
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| 45 | bool signalled; |
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| 46 | }; |
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[82f4063] | 47 | P9_EMBEDDED( info_thread(L), dlink(info_thread(L)) ) |
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[848439f] | 48 | |
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[e84ab3d] | 49 | void ?{}( info_thread(L) & this, thread$ * t, uintptr_t info, L * l ) { |
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[848439f] | 50 | this.t = t; |
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| 51 | this.info = info; |
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[ac5816d] | 52 | this.lock = l; |
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[848439f] | 53 | } |
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| 54 | |
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[ac5816d] | 55 | void ^?{}( info_thread(L) & this ) {} |
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[848439f] | 56 | } |
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[cad1df1] | 57 | |
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[ac5816d] | 58 | //----------------------------------------------------------------------------- |
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| 59 | // Blocking Locks |
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[848439f] | 60 | void ?{}( blocking_lock & this, bool multi_acquisition, bool strict_owner ) { |
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| 61 | this.lock{}; |
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| 62 | this.blocked_threads{}; |
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| 63 | this.wait_count = 0; |
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| 64 | this.multi_acquisition = multi_acquisition; |
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| 65 | this.strict_owner = strict_owner; |
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| 66 | this.owner = 0p; |
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| 67 | this.recursion_count = 0; |
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| 68 | } |
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| 69 | |
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[cad1df1] | 70 | void ^?{}( blocking_lock & this ) {} |
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[ab1b971] | 71 | |
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[848439f] | 72 | |
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| 73 | void lock( blocking_lock & this ) with( this ) { |
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| 74 | lock( lock __cfaabi_dbg_ctx2 ); |
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[e84ab3d] | 75 | thread$ * thrd = active_thread(); |
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[ac5816d] | 76 | |
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| 77 | // single acquisition lock is held by current thread |
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| 78 | /* 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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| 79 | |
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| 80 | // lock is held by some other thread |
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| 81 | if ( owner != 0p && owner != thrd ) { |
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[82f4063] | 82 | insert_last( blocked_threads, *thrd ); |
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[848439f] | 83 | wait_count++; |
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| 84 | unlock( lock ); |
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[eeb5023] | 85 | park( ); |
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[ac5816d] | 86 | } |
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| 87 | // multi acquisition lock is held by current thread |
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| 88 | else if ( owner == thrd && multi_acquisition ) { |
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[848439f] | 89 | recursion_count++; |
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| 90 | unlock( lock ); |
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[ac5816d] | 91 | } |
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| 92 | // lock isn't held |
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| 93 | else { |
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| 94 | owner = thrd; |
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[848439f] | 95 | recursion_count = 1; |
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| 96 | unlock( lock ); |
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| 97 | } |
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| 98 | } |
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| 99 | |
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| 100 | bool try_lock( blocking_lock & this ) with( this ) { |
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| 101 | bool ret = false; |
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| 102 | lock( lock __cfaabi_dbg_ctx2 ); |
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[ac5816d] | 103 | |
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| 104 | // lock isn't held |
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| 105 | if ( owner == 0p ) { |
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[6a8882c] | 106 | owner = active_thread(); |
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| 107 | recursion_count = 1; |
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[848439f] | 108 | ret = true; |
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[ac5816d] | 109 | } |
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| 110 | // multi acquisition lock is held by current thread |
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| 111 | else if ( owner == active_thread() && multi_acquisition ) { |
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[848439f] | 112 | recursion_count++; |
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| 113 | ret = true; |
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| 114 | } |
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[ac5816d] | 115 | |
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[848439f] | 116 | unlock( lock ); |
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| 117 | return ret; |
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| 118 | } |
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| 119 | |
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[c18bf9e] | 120 | static void pop_and_set_new_owner( blocking_lock & this ) with( this ) { |
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[e84ab3d] | 121 | thread$ * t = &try_pop_front( blocked_threads ); |
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[cad1df1] | 122 | owner = t; |
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| 123 | recursion_count = ( t ? 1 : 0 ); |
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[f9b68d6] | 124 | if ( t ) wait_count--; |
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[cad1df1] | 125 | unpark( t ); |
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| 126 | } |
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| 127 | |
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| 128 | void unlock( blocking_lock & this ) with( this ) { |
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| 129 | lock( lock __cfaabi_dbg_ctx2 ); |
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[ac5816d] | 130 | /* paranoid */ verifyf( owner != 0p, "Attempt to release lock %p that isn't held", &this ); |
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[22b7579] | 131 | /* 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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| 132 | /* 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] | 133 | |
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| 134 | // if recursion count is zero release lock and set new owner if one is waiting |
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[848439f] | 135 | recursion_count--; |
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[ac5816d] | 136 | if ( recursion_count == 0 ) { |
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[cad1df1] | 137 | pop_and_set_new_owner( this ); |
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[848439f] | 138 | } |
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| 139 | unlock( lock ); |
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| 140 | } |
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| 141 | |
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| 142 | size_t wait_count( blocking_lock & this ) with( this ) { |
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| 143 | return wait_count; |
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| 144 | } |
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| 145 | |
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[e84ab3d] | 146 | void on_notify( blocking_lock & this, thread$ * t ) with( this ) { |
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[ac5816d] | 147 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 148 | // lock held |
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| 149 | if ( owner != 0p ) { |
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[82f4063] | 150 | insert_last( blocked_threads, *t ); |
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[848439f] | 151 | wait_count++; |
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| 152 | unlock( lock ); |
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[ac5816d] | 153 | } |
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| 154 | // lock not held |
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| 155 | else { |
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[848439f] | 156 | owner = t; |
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[6a8882c] | 157 | recursion_count = 1; |
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[eeb5023] | 158 | unpark( t ); |
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[848439f] | 159 | unlock( lock ); |
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| 160 | } |
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| 161 | } |
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| 162 | |
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[22b7579] | 163 | size_t on_wait( blocking_lock & this ) with( this ) { |
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[ac5816d] | 164 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 165 | /* paranoid */ verifyf( owner != 0p, "Attempt to release lock %p that isn't held", &this ); |
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| 166 | /* 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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| 167 | |
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[22b7579] | 168 | size_t ret = recursion_count; |
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| 169 | |
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[cad1df1] | 170 | pop_and_set_new_owner( this ); |
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[848439f] | 171 | unlock( lock ); |
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[22b7579] | 172 | return ret; |
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| 173 | } |
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| 174 | |
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| 175 | void on_wakeup( blocking_lock & this, size_t recursion ) with( this ) { |
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| 176 | recursion_count = recursion; |
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[848439f] | 177 | } |
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| 178 | |
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[ac5816d] | 179 | //----------------------------------------------------------------------------- |
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| 180 | // alarm node wrapper |
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[fd54fef] | 181 | forall(L & | is_blocking_lock(L)) { |
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[c20533ea] | 182 | struct alarm_node_wrap { |
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| 183 | alarm_node_t alarm_node; |
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| 184 | condition_variable(L) * cond; |
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[90a10e8] | 185 | info_thread(L) * info_thd; |
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[c20533ea] | 186 | }; |
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| 187 | |
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[c457dc41] | 188 | 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] | 189 | this.alarm_node{ callback, alarm, period }; |
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[ac5816d] | 190 | this.cond = c; |
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[90a10e8] | 191 | this.info_thd = i; |
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[c20533ea] | 192 | } |
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| 193 | |
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| 194 | void ^?{}( alarm_node_wrap(L) & this ) { } |
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[848439f] | 195 | |
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[c18bf9e] | 196 | static void timeout_handler ( alarm_node_wrap(L) & this ) with( this ) { |
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[ac5816d] | 197 | // This condition_variable member is called from the kernel, and therefore, cannot block, but it can spin. |
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| 198 | lock( cond->lock __cfaabi_dbg_ctx2 ); |
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| 199 | |
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| 200 | // this check is necessary to avoid a race condition since this timeout handler |
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| 201 | // may still be called after a thread has been removed from the queue but |
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| 202 | // before the alarm is unregistered |
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[82f4063] | 203 | if ( (*info_thd)`isListed ) { // is thread on queue |
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[90a10e8] | 204 | info_thd->signalled = false; |
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[ac5816d] | 205 | // remove this thread O(1) |
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[82f4063] | 206 | remove( *info_thd ); |
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[6a8882c] | 207 | cond->count--; |
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[90a10e8] | 208 | if( info_thd->lock ) { |
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[ac5816d] | 209 | // call lock's on_notify if a lock was passed |
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[90a10e8] | 210 | on_notify(*info_thd->lock, info_thd->t); |
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[ac5816d] | 211 | } else { |
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| 212 | // otherwise wake thread |
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[90a10e8] | 213 | unpark( info_thd->t ); |
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[ac5816d] | 214 | } |
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| 215 | } |
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| 216 | unlock( cond->lock ); |
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[848439f] | 217 | } |
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| 218 | |
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[797a193] | 219 | // this casts the alarm node to our wrapped type since we used type erasure |
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[c18bf9e] | 220 | static void alarm_node_wrap_cast( alarm_node_t & a ) { timeout_handler( (alarm_node_wrap(L) &)a ); } |
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[c20533ea] | 221 | } |
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| 222 | |
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[ac5816d] | 223 | //----------------------------------------------------------------------------- |
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[7f958c4] | 224 | // Synchronization Locks |
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[fd54fef] | 225 | forall(L & | is_blocking_lock(L)) { |
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[c20533ea] | 226 | |
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[7f958c4] | 227 | //----------------------------------------------------------------------------- |
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| 228 | // condition variable |
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[848439f] | 229 | void ?{}( condition_variable(L) & this ){ |
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[eeb5023] | 230 | this.lock{}; |
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| 231 | this.blocked_threads{}; |
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| 232 | this.count = 0; |
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[848439f] | 233 | } |
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| 234 | |
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[cad1df1] | 235 | void ^?{}( condition_variable(L) & this ){ } |
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[848439f] | 236 | |
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[c18bf9e] | 237 | static void process_popped( condition_variable(L) & this, info_thread(L) & popped ) with( this ) { |
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[cad1df1] | 238 | if(&popped != 0p) { |
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[dff1fd1] | 239 | popped.signalled = true; |
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[eeb5023] | 240 | count--; |
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[cad1df1] | 241 | if (popped.lock) { |
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[ac5816d] | 242 | // if lock passed call on_notify |
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| 243 | on_notify(*popped.lock, popped.t); |
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[848439f] | 244 | } else { |
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[ac5816d] | 245 | // otherwise wake thread |
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| 246 | unpark(popped.t); |
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[848439f] | 247 | } |
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| 248 | } |
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[cad1df1] | 249 | } |
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| 250 | |
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| 251 | bool notify_one( condition_variable(L) & this ) with( this ) { |
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| 252 | lock( lock __cfaabi_dbg_ctx2 ); |
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[82f4063] | 253 | bool ret = ! blocked_threads`isEmpty; |
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| 254 | process_popped(this, try_pop_front( blocked_threads )); |
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[848439f] | 255 | unlock( lock ); |
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| 256 | return ret; |
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| 257 | } |
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| 258 | |
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[eeb5023] | 259 | bool notify_all( condition_variable(L) & this ) with(this) { |
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[848439f] | 260 | lock( lock __cfaabi_dbg_ctx2 ); |
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[82f4063] | 261 | bool ret = ! blocked_threads`isEmpty; |
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| 262 | while( ! blocked_threads`isEmpty ) { |
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| 263 | process_popped(this, try_pop_front( blocked_threads )); |
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[848439f] | 264 | } |
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| 265 | unlock( lock ); |
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| 266 | return ret; |
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| 267 | } |
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| 268 | |
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[eeb5023] | 269 | uintptr_t front( condition_variable(L) & this ) with(this) { |
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[82f4063] | 270 | return blocked_threads`isEmpty ? NULL : blocked_threads`first.info; |
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[848439f] | 271 | } |
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| 272 | |
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[22b7579] | 273 | bool empty( condition_variable(L) & this ) with(this) { |
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| 274 | lock( lock __cfaabi_dbg_ctx2 ); |
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[82f4063] | 275 | bool ret = blocked_threads`isEmpty; |
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[22b7579] | 276 | unlock( lock ); |
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| 277 | return ret; |
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| 278 | } |
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[cad1df1] | 279 | |
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| 280 | int counter( condition_variable(L) & this ) with(this) { return count; } |
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[848439f] | 281 | |
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[c18bf9e] | 282 | static size_t queue_and_get_recursion( condition_variable(L) & this, info_thread(L) * i ) with(this) { |
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[ac5816d] | 283 | // add info_thread to waiting queue |
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[82f4063] | 284 | insert_last( blocked_threads, *i ); |
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[cad1df1] | 285 | count++; |
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| 286 | size_t recursion_count = 0; |
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[ac5816d] | 287 | if (i->lock) { |
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| 288 | // if lock was passed get recursion count to reset to after waking thread |
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[22b7579] | 289 | recursion_count = on_wait( *i->lock ); |
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[cad1df1] | 290 | } |
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| 291 | return recursion_count; |
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[848439f] | 292 | } |
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| 293 | |
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[cad1df1] | 294 | // helper for wait()'s' with no timeout |
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[c18bf9e] | 295 | static void queue_info_thread( condition_variable(L) & this, info_thread(L) & i ) with(this) { |
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[848439f] | 296 | lock( lock __cfaabi_dbg_ctx2 ); |
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[cad1df1] | 297 | size_t recursion_count = queue_and_get_recursion(this, &i); |
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[848439f] | 298 | unlock( lock ); |
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[ac5816d] | 299 | |
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| 300 | // blocks here |
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| 301 | park( ); |
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| 302 | |
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| 303 | // resets recursion count here after waking |
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[22b7579] | 304 | if (i.lock) on_wakeup(*i.lock, recursion_count); |
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[848439f] | 305 | } |
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| 306 | |
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[ac5816d] | 307 | #define WAIT( u, l ) \ |
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| 308 | info_thread( L ) i = { active_thread(), u, l }; \ |
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| 309 | queue_info_thread( this, i ); |
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| 310 | |
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[eeb5023] | 311 | // helper for wait()'s' with a timeout |
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[c18bf9e] | 312 | static 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] | 313 | lock( lock __cfaabi_dbg_ctx2 ); |
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[cad1df1] | 314 | size_t recursion_count = queue_and_get_recursion(this, &info); |
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[afd7faf] | 315 | alarm_node_wrap(L) node_wrap = { t, 0`s, callback, &this, &info }; |
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[eeb5023] | 316 | register_self( &node_wrap.alarm_node ); |
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[848439f] | 317 | unlock( lock ); |
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| 318 | |
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[ac5816d] | 319 | // blocks here |
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| 320 | park(); |
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[848439f] | 321 | |
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[ac5816d] | 322 | // unregisters alarm so it doesn't go off if this happens first |
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| 323 | unregister_self( &node_wrap.alarm_node ); |
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[848439f] | 324 | |
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[ac5816d] | 325 | // resets recursion count here after waking |
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[22b7579] | 326 | if (info.lock) on_wakeup(*info.lock, recursion_count); |
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[848439f] | 327 | } |
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| 328 | |
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[ac5816d] | 329 | #define WAIT_TIME( u, l, t ) \ |
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| 330 | info_thread( L ) i = { active_thread(), u, l }; \ |
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[afd7faf] | 331 | queue_info_thread_timeout(this, i, t, alarm_node_wrap_cast ); \ |
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[dff1fd1] | 332 | return i.signalled; |
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[848439f] | 333 | |
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[ac5816d] | 334 | void wait( condition_variable(L) & this ) with(this) { WAIT( 0, 0p ) } |
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| 335 | void wait( condition_variable(L) & this, uintptr_t info ) with(this) { WAIT( info, 0p ) } |
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| 336 | void wait( condition_variable(L) & this, L & l ) with(this) { WAIT( 0, &l ) } |
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| 337 | void wait( condition_variable(L) & this, L & l, uintptr_t info ) with(this) { WAIT( info, &l ) } |
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| 338 | |
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[c457dc41] | 339 | bool wait( condition_variable(L) & this, Duration duration ) with(this) { WAIT_TIME( 0 , 0p , duration ) } |
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| 340 | bool wait( condition_variable(L) & this, uintptr_t info, Duration duration ) with(this) { WAIT_TIME( info, 0p , duration ) } |
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| 341 | bool wait( condition_variable(L) & this, L & l, Duration duration ) with(this) { WAIT_TIME( 0 , &l , duration ) } |
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| 342 | 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] | 343 | |
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| 344 | //----------------------------------------------------------------------------- |
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| 345 | // fast_cond_var |
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| 346 | void ?{}( fast_cond_var(L) & this ){ |
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[c18bf9e] | 347 | this.blocked_threads{}; |
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[7f958c4] | 348 | #ifdef __CFA_DEBUG__ |
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| 349 | this.lock_used = 0p; |
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| 350 | #endif |
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| 351 | } |
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| 352 | void ^?{}( fast_cond_var(L) & this ){ } |
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| 353 | |
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| 354 | bool notify_one( fast_cond_var(L) & this ) with(this) { |
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| 355 | bool ret = ! blocked_threads`isEmpty; |
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| 356 | if ( ret ) { |
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| 357 | info_thread(L) & popped = try_pop_front( blocked_threads ); |
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| 358 | on_notify(*popped.lock, popped.t); |
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| 359 | } |
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| 360 | return ret; |
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| 361 | } |
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| 362 | bool notify_all( fast_cond_var(L) & this ) with(this) { |
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| 363 | bool ret = ! blocked_threads`isEmpty; |
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| 364 | while( ! blocked_threads`isEmpty ) { |
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| 365 | info_thread(L) & popped = try_pop_front( blocked_threads ); |
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| 366 | on_notify(*popped.lock, popped.t); |
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| 367 | } |
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| 368 | return ret; |
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| 369 | } |
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| 370 | |
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| 371 | uintptr_t front( fast_cond_var(L) & this ) with(this) { return blocked_threads`isEmpty ? NULL : blocked_threads`first.info; } |
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| 372 | bool empty ( fast_cond_var(L) & this ) with(this) { return blocked_threads`isEmpty; } |
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| 373 | |
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| 374 | void wait( fast_cond_var(L) & this, L & l ) { |
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| 375 | wait( this, l, 0 ); |
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| 376 | } |
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| 377 | |
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| 378 | void wait( fast_cond_var(L) & this, L & l, uintptr_t info ) with(this) { |
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| 379 | // brand cond lock with lock |
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| 380 | #ifdef __CFA_DEBUG__ |
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| 381 | if ( lock_used == 0p ) lock_used = &l; |
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| 382 | else { assert(lock_used == &l); } |
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| 383 | #endif |
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| 384 | info_thread( L ) i = { active_thread(), info, &l }; |
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| 385 | insert_last( blocked_threads, i ); |
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| 386 | size_t recursion_count = on_wait( *i.lock ); |
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| 387 | park( ); |
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| 388 | on_wakeup(*i.lock, recursion_count); |
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| 389 | } |
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[848439f] | 390 | } |
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[454f478] | 391 | |
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| 392 | //----------------------------------------------------------------------------- |
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| 393 | // Semaphore |
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| 394 | void ?{}( semaphore & this, int count = 1 ) { |
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| 395 | (this.lock){}; |
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| 396 | this.count = count; |
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| 397 | (this.waiting){}; |
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| 398 | } |
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| 399 | void ^?{}(semaphore & this) {} |
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| 400 | |
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| 401 | bool P(semaphore & this) with( this ){ |
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| 402 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 403 | count -= 1; |
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| 404 | if ( count < 0 ) { |
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| 405 | // queue current task |
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| 406 | append( waiting, active_thread() ); |
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| 407 | |
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| 408 | // atomically release spin lock and block |
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| 409 | unlock( lock ); |
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| 410 | park(); |
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| 411 | return true; |
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| 412 | } |
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| 413 | else { |
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| 414 | unlock( lock ); |
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| 415 | return false; |
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| 416 | } |
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| 417 | } |
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| 418 | |
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[e84ab3d] | 419 | thread$ * V (semaphore & this, const bool doUnpark ) with( this ) { |
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| 420 | thread$ * thrd = 0p; |
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[454f478] | 421 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 422 | count += 1; |
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| 423 | if ( count <= 0 ) { |
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| 424 | // remove task at head of waiting list |
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| 425 | thrd = pop_head( waiting ); |
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| 426 | } |
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| 427 | |
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| 428 | unlock( lock ); |
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| 429 | |
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| 430 | // make new owner |
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[22b7579] | 431 | if( doUnpark ) unpark( thrd ); |
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| 432 | |
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| 433 | return thrd; |
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| 434 | } |
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[454f478] | 435 | |
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[22b7579] | 436 | bool V(semaphore & this) with( this ) { |
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[e84ab3d] | 437 | thread$ * thrd = V(this, true); |
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[454f478] | 438 | return thrd != 0p; |
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| 439 | } |
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| 440 | |
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| 441 | bool V(semaphore & this, unsigned diff) with( this ) { |
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[e84ab3d] | 442 | thread$ * thrd = 0p; |
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[454f478] | 443 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 444 | int release = max(-count, (int)diff); |
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| 445 | count += diff; |
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| 446 | for(release) { |
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| 447 | unpark( pop_head( waiting ) ); |
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| 448 | } |
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| 449 | |
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| 450 | unlock( lock ); |
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| 451 | |
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| 452 | return thrd != 0p; |
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| 453 | } |
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