[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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| 21 | #include "kernel_private.hfa" |
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| 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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| 30 | // used to put info_thread on a dl queue (aka sequence) |
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| 31 | inline Seqable; |
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| 32 | |
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| 33 | // waiting thread |
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| 34 | struct $thread * t; |
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| 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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[848439f] | 45 | |
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[ac5816d] | 46 | void ?{}( info_thread(L) & this, $thread * t, uintptr_t info, L * l ) { |
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[cad1df1] | 47 | ((Seqable &) this){}; |
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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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[c131a02] | 54 | |
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| 55 | info_thread(L) *& Back( info_thread(L) * this ) { |
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| 56 | return (info_thread(L) *)Back( (Seqable *)this ); |
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| 57 | } |
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| 58 | |
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| 59 | info_thread(L) *& Next( info_thread(L) * this ) { |
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| 60 | return (info_thread(L) *)Next( (Colable *)this ); |
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| 61 | } |
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[848439f] | 62 | } |
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[cad1df1] | 63 | |
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[ac5816d] | 64 | //----------------------------------------------------------------------------- |
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| 65 | // Blocking Locks |
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[848439f] | 66 | void ?{}( blocking_lock & this, bool multi_acquisition, bool strict_owner ) { |
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| 67 | this.lock{}; |
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| 68 | this.blocked_threads{}; |
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| 69 | this.wait_count = 0; |
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| 70 | this.multi_acquisition = multi_acquisition; |
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| 71 | this.strict_owner = strict_owner; |
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| 72 | this.owner = 0p; |
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| 73 | this.recursion_count = 0; |
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| 74 | } |
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| 75 | |
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[cad1df1] | 76 | void ^?{}( blocking_lock & this ) {} |
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[ab1b971] | 77 | |
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[848439f] | 78 | |
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| 79 | void lock( blocking_lock & this ) with( this ) { |
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| 80 | lock( lock __cfaabi_dbg_ctx2 ); |
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[ac5816d] | 81 | $thread * thrd = active_thread(); |
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| 82 | |
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| 83 | // single acquisition lock is held by current thread |
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| 84 | /* 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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| 85 | |
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| 86 | // lock is held by some other thread |
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| 87 | if ( owner != 0p && owner != thrd ) { |
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| 88 | addTail( blocked_threads, *thrd ); |
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[848439f] | 89 | wait_count++; |
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| 90 | unlock( lock ); |
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[eeb5023] | 91 | park( ); |
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[ac5816d] | 92 | } |
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| 93 | // multi acquisition lock is held by current thread |
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| 94 | else if ( owner == thrd && multi_acquisition ) { |
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[848439f] | 95 | recursion_count++; |
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| 96 | unlock( lock ); |
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[ac5816d] | 97 | } |
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| 98 | // lock isn't held |
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| 99 | else { |
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| 100 | owner = thrd; |
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[848439f] | 101 | recursion_count = 1; |
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| 102 | unlock( lock ); |
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| 103 | } |
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| 104 | } |
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| 105 | |
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| 106 | bool try_lock( blocking_lock & this ) with( this ) { |
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| 107 | bool ret = false; |
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| 108 | lock( lock __cfaabi_dbg_ctx2 ); |
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[ac5816d] | 109 | |
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| 110 | // lock isn't held |
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| 111 | if ( owner == 0p ) { |
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[6a8882c] | 112 | owner = active_thread(); |
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| 113 | recursion_count = 1; |
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[848439f] | 114 | ret = true; |
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[ac5816d] | 115 | } |
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| 116 | // multi acquisition lock is held by current thread |
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| 117 | else if ( owner == active_thread() && multi_acquisition ) { |
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[848439f] | 118 | recursion_count++; |
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| 119 | ret = true; |
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| 120 | } |
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[ac5816d] | 121 | |
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[848439f] | 122 | unlock( lock ); |
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| 123 | return ret; |
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| 124 | } |
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| 125 | |
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[cad1df1] | 126 | void pop_and_set_new_owner( blocking_lock & this ) with( this ) { |
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[c131a02] | 127 | $thread * t = &dropHead( blocked_threads ); |
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[cad1df1] | 128 | owner = t; |
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| 129 | recursion_count = ( t ? 1 : 0 ); |
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| 130 | wait_count--; |
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| 131 | unpark( t ); |
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| 132 | } |
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| 133 | |
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| 134 | void unlock( blocking_lock & this ) with( this ) { |
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| 135 | lock( lock __cfaabi_dbg_ctx2 ); |
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[ac5816d] | 136 | /* paranoid */ verifyf( owner != 0p, "Attempt to release lock %p that isn't held", &this ); |
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[22b7579] | 137 | /* 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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| 138 | /* 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] | 139 | |
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| 140 | // if recursion count is zero release lock and set new owner if one is waiting |
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[848439f] | 141 | recursion_count--; |
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[ac5816d] | 142 | if ( recursion_count == 0 ) { |
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[cad1df1] | 143 | pop_and_set_new_owner( this ); |
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[848439f] | 144 | } |
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| 145 | unlock( lock ); |
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| 146 | } |
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| 147 | |
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| 148 | size_t wait_count( blocking_lock & this ) with( this ) { |
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| 149 | return wait_count; |
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| 150 | } |
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| 151 | |
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[797a193] | 152 | void on_notify( blocking_lock & this, $thread * t ) with( this ) { |
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[ac5816d] | 153 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 154 | // lock held |
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| 155 | if ( owner != 0p ) { |
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[c131a02] | 156 | addTail( blocked_threads, *t ); |
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[848439f] | 157 | wait_count++; |
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| 158 | unlock( lock ); |
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[ac5816d] | 159 | } |
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| 160 | // lock not held |
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| 161 | else { |
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[848439f] | 162 | owner = t; |
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[6a8882c] | 163 | recursion_count = 1; |
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[eeb5023] | 164 | unpark( t ); |
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[848439f] | 165 | unlock( lock ); |
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| 166 | } |
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| 167 | } |
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| 168 | |
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[22b7579] | 169 | size_t on_wait( blocking_lock & this ) with( this ) { |
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[ac5816d] | 170 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 171 | /* paranoid */ verifyf( owner != 0p, "Attempt to release lock %p that isn't held", &this ); |
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| 172 | /* 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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| 173 | |
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[22b7579] | 174 | size_t ret = recursion_count; |
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| 175 | |
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[cad1df1] | 176 | pop_and_set_new_owner( this ); |
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[848439f] | 177 | unlock( lock ); |
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[22b7579] | 178 | return ret; |
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| 179 | } |
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| 180 | |
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| 181 | void on_wakeup( blocking_lock & this, size_t recursion ) with( this ) { |
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| 182 | recursion_count = recursion; |
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[848439f] | 183 | } |
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| 184 | |
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[ac5816d] | 185 | //----------------------------------------------------------------------------- |
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| 186 | // alarm node wrapper |
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[fd54fef] | 187 | forall(L & | is_blocking_lock(L)) { |
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[c20533ea] | 188 | struct alarm_node_wrap { |
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| 189 | alarm_node_t alarm_node; |
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| 190 | condition_variable(L) * cond; |
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[90a10e8] | 191 | info_thread(L) * info_thd; |
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[c20533ea] | 192 | }; |
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| 193 | |
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[c457dc41] | 194 | 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] | 195 | this.alarm_node{ callback, alarm, period }; |
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[ac5816d] | 196 | this.cond = c; |
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[90a10e8] | 197 | this.info_thd = i; |
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[c20533ea] | 198 | } |
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| 199 | |
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| 200 | void ^?{}( alarm_node_wrap(L) & this ) { } |
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[848439f] | 201 | |
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[c5bbb9b] | 202 | void timeout_handler ( alarm_node_wrap(L) & this ) with( this ) { |
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[ac5816d] | 203 | // This condition_variable member is called from the kernel, and therefore, cannot block, but it can spin. |
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| 204 | lock( cond->lock __cfaabi_dbg_ctx2 ); |
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| 205 | |
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| 206 | // this check is necessary to avoid a race condition since this timeout handler |
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| 207 | // may still be called after a thread has been removed from the queue but |
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| 208 | // before the alarm is unregistered |
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[90a10e8] | 209 | if ( listed(info_thd) ) { // is thread on queue |
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| 210 | info_thd->signalled = false; |
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[ac5816d] | 211 | // remove this thread O(1) |
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[90a10e8] | 212 | remove( cond->blocked_threads, *info_thd ); |
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[6a8882c] | 213 | cond->count--; |
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[90a10e8] | 214 | if( info_thd->lock ) { |
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[ac5816d] | 215 | // call lock's on_notify if a lock was passed |
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[90a10e8] | 216 | on_notify(*info_thd->lock, info_thd->t); |
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[ac5816d] | 217 | } else { |
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| 218 | // otherwise wake thread |
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[90a10e8] | 219 | unpark( info_thd->t ); |
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[ac5816d] | 220 | } |
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| 221 | } |
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| 222 | unlock( cond->lock ); |
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[848439f] | 223 | } |
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| 224 | |
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[797a193] | 225 | // this casts the alarm node to our wrapped type since we used type erasure |
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[cad1df1] | 226 | void alarm_node_wrap_cast( alarm_node_t & a ) { timeout_handler( (alarm_node_wrap(L) &)a ); } |
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[c20533ea] | 227 | } |
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| 228 | |
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[ac5816d] | 229 | //----------------------------------------------------------------------------- |
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| 230 | // condition variable |
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[fd54fef] | 231 | forall(L & | is_blocking_lock(L)) { |
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[c20533ea] | 232 | |
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[848439f] | 233 | void ?{}( condition_variable(L) & this ){ |
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[eeb5023] | 234 | this.lock{}; |
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| 235 | this.blocked_threads{}; |
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| 236 | this.count = 0; |
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[848439f] | 237 | } |
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| 238 | |
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[cad1df1] | 239 | void ^?{}( condition_variable(L) & this ){ } |
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[848439f] | 240 | |
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[cad1df1] | 241 | void process_popped( condition_variable(L) & this, info_thread(L) & popped ) with( this ) { |
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| 242 | if(&popped != 0p) { |
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[dff1fd1] | 243 | popped.signalled = true; |
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[eeb5023] | 244 | count--; |
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[cad1df1] | 245 | if (popped.lock) { |
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[ac5816d] | 246 | // if lock passed call on_notify |
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| 247 | on_notify(*popped.lock, popped.t); |
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[848439f] | 248 | } else { |
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[ac5816d] | 249 | // otherwise wake thread |
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| 250 | unpark(popped.t); |
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[848439f] | 251 | } |
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| 252 | } |
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[cad1df1] | 253 | } |
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| 254 | |
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| 255 | bool notify_one( condition_variable(L) & this ) with( this ) { |
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| 256 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 257 | bool ret = !empty(blocked_threads); |
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| 258 | process_popped(this, dropHead( blocked_threads )); |
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[848439f] | 259 | unlock( lock ); |
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| 260 | return ret; |
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| 261 | } |
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| 262 | |
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[eeb5023] | 263 | bool notify_all( condition_variable(L) & this ) with(this) { |
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[848439f] | 264 | lock( lock __cfaabi_dbg_ctx2 ); |
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[cad1df1] | 265 | bool ret = !empty(blocked_threads); |
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| 266 | while( !empty(blocked_threads) ) { |
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| 267 | process_popped(this, dropHead( blocked_threads )); |
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[848439f] | 268 | } |
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| 269 | unlock( lock ); |
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| 270 | return ret; |
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| 271 | } |
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| 272 | |
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[eeb5023] | 273 | uintptr_t front( condition_variable(L) & this ) with(this) { |
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[cad1df1] | 274 | return empty(blocked_threads) ? NULL : head(blocked_threads).info; |
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[848439f] | 275 | } |
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| 276 | |
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[22b7579] | 277 | bool empty( condition_variable(L) & this ) with(this) { |
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| 278 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 279 | bool ret = empty(blocked_threads); |
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| 280 | unlock( lock ); |
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| 281 | return ret; |
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| 282 | } |
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[cad1df1] | 283 | |
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| 284 | int counter( condition_variable(L) & this ) with(this) { return count; } |
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[848439f] | 285 | |
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[cad1df1] | 286 | size_t queue_and_get_recursion( condition_variable(L) & this, info_thread(L) * i ) with(this) { |
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[ac5816d] | 287 | // add info_thread to waiting queue |
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| 288 | addTail( blocked_threads, *i ); |
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[cad1df1] | 289 | count++; |
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| 290 | size_t recursion_count = 0; |
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[ac5816d] | 291 | if (i->lock) { |
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| 292 | // if lock was passed get recursion count to reset to after waking thread |
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[22b7579] | 293 | recursion_count = on_wait( *i->lock ); |
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[cad1df1] | 294 | } |
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| 295 | return recursion_count; |
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[848439f] | 296 | } |
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| 297 | |
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[cad1df1] | 298 | // helper for wait()'s' with no timeout |
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[eeb5023] | 299 | void queue_info_thread( condition_variable(L) & this, info_thread(L) & i ) with(this) { |
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[848439f] | 300 | lock( lock __cfaabi_dbg_ctx2 ); |
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[cad1df1] | 301 | size_t recursion_count = queue_and_get_recursion(this, &i); |
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[848439f] | 302 | unlock( lock ); |
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[ac5816d] | 303 | |
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| 304 | // blocks here |
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| 305 | park( ); |
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| 306 | |
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| 307 | // resets recursion count here after waking |
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[22b7579] | 308 | if (i.lock) on_wakeup(*i.lock, recursion_count); |
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[848439f] | 309 | } |
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| 310 | |
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[ac5816d] | 311 | #define WAIT( u, l ) \ |
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| 312 | info_thread( L ) i = { active_thread(), u, l }; \ |
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| 313 | queue_info_thread( this, i ); |
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| 314 | |
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[eeb5023] | 315 | // helper for wait()'s' with a timeout |
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[afd7faf] | 316 | 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] | 317 | lock( lock __cfaabi_dbg_ctx2 ); |
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[cad1df1] | 318 | size_t recursion_count = queue_and_get_recursion(this, &info); |
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[afd7faf] | 319 | alarm_node_wrap(L) node_wrap = { t, 0`s, callback, &this, &info }; |
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[eeb5023] | 320 | register_self( &node_wrap.alarm_node ); |
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[848439f] | 321 | unlock( lock ); |
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| 322 | |
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[ac5816d] | 323 | // blocks here |
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| 324 | park(); |
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[848439f] | 325 | |
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[ac5816d] | 326 | // unregisters alarm so it doesn't go off if this happens first |
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| 327 | unregister_self( &node_wrap.alarm_node ); |
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[848439f] | 328 | |
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[ac5816d] | 329 | // resets recursion count here after waking |
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[22b7579] | 330 | if (info.lock) on_wakeup(*info.lock, recursion_count); |
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[848439f] | 331 | } |
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| 332 | |
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[ac5816d] | 333 | #define WAIT_TIME( u, l, t ) \ |
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| 334 | info_thread( L ) i = { active_thread(), u, l }; \ |
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[afd7faf] | 335 | queue_info_thread_timeout(this, i, t, alarm_node_wrap_cast ); \ |
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[dff1fd1] | 336 | return i.signalled; |
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[848439f] | 337 | |
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[ac5816d] | 338 | void wait( condition_variable(L) & this ) with(this) { WAIT( 0, 0p ) } |
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| 339 | void wait( condition_variable(L) & this, uintptr_t info ) with(this) { WAIT( info, 0p ) } |
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| 340 | void wait( condition_variable(L) & this, L & l ) with(this) { WAIT( 0, &l ) } |
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| 341 | void wait( condition_variable(L) & this, L & l, uintptr_t info ) with(this) { WAIT( info, &l ) } |
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| 342 | |
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[c457dc41] | 343 | bool wait( condition_variable(L) & this, Duration duration ) with(this) { WAIT_TIME( 0 , 0p , duration ) } |
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| 344 | bool wait( condition_variable(L) & this, uintptr_t info, Duration duration ) with(this) { WAIT_TIME( info, 0p , duration ) } |
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| 345 | bool wait( condition_variable(L) & this, L & l, Duration duration ) with(this) { WAIT_TIME( 0 , &l , duration ) } |
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| 346 | bool wait( condition_variable(L) & this, L & l, uintptr_t info, Duration duration ) with(this) { WAIT_TIME( info, &l , duration ) } |
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[848439f] | 347 | } |
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[454f478] | 348 | |
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| 349 | //----------------------------------------------------------------------------- |
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| 350 | // Semaphore |
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| 351 | void ?{}( semaphore & this, int count = 1 ) { |
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| 352 | (this.lock){}; |
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| 353 | this.count = count; |
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| 354 | (this.waiting){}; |
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| 355 | } |
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| 356 | void ^?{}(semaphore & this) {} |
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| 357 | |
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| 358 | bool P(semaphore & this) with( this ){ |
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| 359 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 360 | count -= 1; |
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| 361 | if ( count < 0 ) { |
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| 362 | // queue current task |
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| 363 | append( waiting, active_thread() ); |
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| 364 | |
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| 365 | // atomically release spin lock and block |
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| 366 | unlock( lock ); |
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| 367 | park(); |
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| 368 | return true; |
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| 369 | } |
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| 370 | else { |
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| 371 | unlock( lock ); |
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| 372 | return false; |
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| 373 | } |
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| 374 | } |
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| 375 | |
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[22b7579] | 376 | $thread * V (semaphore & this, const bool doUnpark ) with( this ) { |
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[454f478] | 377 | $thread * thrd = 0p; |
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| 378 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 379 | count += 1; |
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| 380 | if ( count <= 0 ) { |
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| 381 | // remove task at head of waiting list |
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| 382 | thrd = pop_head( waiting ); |
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| 383 | } |
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| 384 | |
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| 385 | unlock( lock ); |
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| 386 | |
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| 387 | // make new owner |
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[22b7579] | 388 | if( doUnpark ) unpark( thrd ); |
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| 389 | |
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| 390 | return thrd; |
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| 391 | } |
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[454f478] | 392 | |
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[22b7579] | 393 | bool V(semaphore & this) with( this ) { |
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| 394 | $thread * thrd = V(this, true); |
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[454f478] | 395 | return thrd != 0p; |
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| 396 | } |
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| 397 | |
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| 398 | bool V(semaphore & this, unsigned diff) with( this ) { |
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| 399 | $thread * thrd = 0p; |
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| 400 | lock( lock __cfaabi_dbg_ctx2 ); |
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| 401 | int release = max(-count, (int)diff); |
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| 402 | count += diff; |
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| 403 | for(release) { |
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| 404 | unpark( pop_head( waiting ) ); |
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| 405 | } |
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| 406 | |
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| 407 | unlock( lock ); |
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| 408 | |
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| 409 | return thrd != 0p; |
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| 410 | } |
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