[629c95a] | 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 | // channel.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 2022 |
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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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[5e4a830] | 17 | #pragma once |
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| 18 | |
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[4a962d8] | 19 | #include <locks.hfa> |
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[d30e3eb] | 20 | #include <list.hfa> |
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[beeff61e] | 21 | #include "select.hfa" |
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[a45e21c] | 22 | |
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| 23 | // returns true if woken due to shutdown |
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| 24 | // blocks thread on list and releases passed lock |
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[beeff61e] | 25 | static inline bool block( dlist( select_node ) & queue, void * elem_ptr, go_mutex & lock ) { |
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| 26 | select_node sn{ active_thread(), elem_ptr }; |
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| 27 | insert_last( queue, sn ); |
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[a45e21c] | 28 | unlock( lock ); |
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| 29 | park(); |
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[beeff61e] | 30 | return sn.extra == 0p; |
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| 31 | } |
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| 32 | |
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| 33 | // Waituntil support (un)register_select helper routine |
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| 34 | // Sets select node avail if not special OR case and then unlocks |
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| 35 | static inline void __set_avail_then_unlock( select_node & node, go_mutex & mutex_lock ) { |
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| 36 | if ( node.park_counter ) __make_select_node_available( node ); |
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| 37 | unlock( mutex_lock ); |
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[a45e21c] | 38 | } |
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| 39 | |
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| 40 | // void * used for some fields since exceptions don't work with parametric polymorphism currently |
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| 41 | exception channel_closed { |
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| 42 | // on failed insert elem is a ptr to the element attempting to be inserted |
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| 43 | // on failed remove elem ptr is 0p |
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| 44 | // on resumption of a failed insert this elem will be inserted |
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| 45 | // so a user may modify it in the resumption handler |
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| 46 | void * elem; |
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| 47 | |
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| 48 | // pointer to chan that is closed |
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| 49 | void * closed_chan; |
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| 50 | }; |
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| 51 | vtable(channel_closed) channel_closed_vt; |
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| 52 | |
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[ded6c2a6] | 53 | static inline bool is_insert( channel_closed & e ) { return e.elem != 0p; } |
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| 54 | static inline bool is_remove( channel_closed & e ) { return e.elem == 0p; } |
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[3eeeb88] | 55 | |
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[a45e21c] | 56 | // #define CHAN_STATS // define this to get channel stats printed in dtor |
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| 57 | |
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[4a962d8] | 58 | forall( T ) { |
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[d30e3eb] | 59 | |
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[a45e21c] | 60 | struct __attribute__((aligned(128))) channel { |
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| 61 | size_t size, front, back, count; |
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[4a962d8] | 62 | T * buffer; |
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[beeff61e] | 63 | dlist( select_node ) prods, cons; // lists of blocked threads |
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[629c95a] | 64 | go_mutex mutex_lock; // MX lock |
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| 65 | bool closed; // indicates channel close/open |
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[a45e21c] | 66 | #ifdef CHAN_STATS |
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[88b49bb] | 67 | size_t p_blocks, p_ops, c_blocks, c_ops; // counts total ops and ops resulting in a blocked thd |
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[a45e21c] | 68 | #endif |
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[4a962d8] | 69 | }; |
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| 70 | |
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| 71 | static inline void ?{}( channel(T) &c, size_t _size ) with(c) { |
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| 72 | size = _size; |
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| 73 | front = back = count = 0; |
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[beeff61e] | 74 | if ( size != 0 ) buffer = aalloc( size ); |
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[4a962d8] | 75 | prods{}; |
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| 76 | cons{}; |
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| 77 | mutex_lock{}; |
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[a45e21c] | 78 | closed = false; |
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| 79 | #ifdef CHAN_STATS |
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[88b49bb] | 80 | p_blocks = 0; |
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| 81 | p_ops = 0; |
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| 82 | c_blocks = 0; |
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| 83 | c_ops = 0; |
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[a45e21c] | 84 | #endif |
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[4a962d8] | 85 | } |
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| 86 | |
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| 87 | static inline void ?{}( channel(T) &c ){ ((channel(T) &)c){ 0 }; } |
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[a45e21c] | 88 | static inline void ^?{}( channel(T) &c ) with(c) { |
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| 89 | #ifdef CHAN_STATS |
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[88b49bb] | 90 | printf("Channel %p Blocks: %lu,\t\tOperations: %lu,\t%.2f%% of ops blocked\n", &c, p_blocks + c_blocks, p_ops + c_ops, ((double)p_blocks + c_blocks)/(p_ops + c_ops) * 100); |
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| 91 | printf("Channel %p Consumer Blocks: %lu,\tConsumer Ops: %lu,\t%.2f%% of Consumer ops blocked\n", &c, p_blocks, p_ops, ((double)p_blocks)/p_ops * 100); |
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| 92 | printf("Channel %p Producer Blocks: %lu,\tProducer Ops: %lu,\t%.2f%% of Producer ops blocked\n", &c, c_blocks, c_ops, ((double)c_blocks)/c_ops * 100); |
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[a45e21c] | 93 | #endif |
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[88b49bb] | 94 | verifyf( __handle_waituntil_OR( cons ) || __handle_waituntil_OR( prods ) || cons`isEmpty && prods`isEmpty, |
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| 95 | "Attempted to delete channel with waiting threads (Deadlock).\n" ); |
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[beeff61e] | 96 | if ( size != 0 ) delete( buffer ); |
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[a45e21c] | 97 | } |
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[5908fb4] | 98 | static inline size_t get_count( channel(T) & chan ) with(chan) { return __atomic_load_n( &count, __ATOMIC_RELAXED ); } |
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| 99 | static inline size_t get_size( channel(T) & chan ) with(chan) { return __atomic_load_n( &size, __ATOMIC_RELAXED ); } |
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[d30e3eb] | 100 | static inline bool has_waiters( channel(T) & chan ) with(chan) { return !cons`isEmpty || !prods`isEmpty; } |
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| 101 | static inline bool has_waiting_consumers( channel(T) & chan ) with(chan) { return !cons`isEmpty; } |
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| 102 | static inline bool has_waiting_producers( channel(T) & chan ) with(chan) { return !prods`isEmpty; } |
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[4a962d8] | 103 | |
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[a45e21c] | 104 | // closes the channel and notifies all blocked threads |
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| 105 | static inline void close( channel(T) & chan ) with(chan) { |
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| 106 | lock( mutex_lock ); |
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| 107 | closed = true; |
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| 108 | |
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| 109 | // flush waiting consumers and producers |
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| 110 | while ( has_waiting_consumers( chan ) ) { |
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[beeff61e] | 111 | if( !__handle_waituntil_OR( cons ) ) // ensure we only signal special OR case threads when they win the race |
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| 112 | break; // if __handle_waituntil_OR returns false cons is empty so break |
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| 113 | cons`first.extra = 0p; |
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[a45e21c] | 114 | wake_one( cons ); |
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| 115 | } |
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| 116 | while ( has_waiting_producers( chan ) ) { |
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[beeff61e] | 117 | if( !__handle_waituntil_OR( prods ) ) // ensure we only signal special OR case threads when they win the race |
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| 118 | break; // if __handle_waituntil_OR returns false prods is empty so break |
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| 119 | prods`first.extra = 0p; |
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[a45e21c] | 120 | wake_one( prods ); |
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| 121 | } |
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| 122 | unlock(mutex_lock); |
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| 123 | } |
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| 124 | |
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| 125 | static inline void is_closed( channel(T) & chan ) with(chan) { return closed; } |
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| 126 | |
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[beeff61e] | 127 | // used to hand an element to a blocked consumer and signal it |
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| 128 | static inline void __cons_handoff( channel(T) & chan, T & elem ) with(chan) { |
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| 129 | memcpy( cons`first.extra, (void *)&elem, sizeof(T) ); // do waiting consumer work |
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| 130 | wake_one( cons ); |
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| 131 | } |
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| 132 | |
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| 133 | // used to hand an element to a blocked producer and signal it |
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| 134 | static inline void __prods_handoff( channel(T) & chan, T & retval ) with(chan) { |
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| 135 | memcpy( (void *)&retval, prods`first.extra, sizeof(T) ); |
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| 136 | wake_one( prods ); |
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| 137 | } |
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| 138 | |
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[a45e21c] | 139 | static inline void flush( channel(T) & chan, T elem ) with(chan) { |
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| 140 | lock( mutex_lock ); |
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| 141 | while ( count == 0 && !cons`isEmpty ) { |
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[beeff61e] | 142 | __cons_handoff( chan, elem ); |
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[a45e21c] | 143 | } |
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| 144 | unlock( mutex_lock ); |
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| 145 | } |
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| 146 | |
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| 147 | // handles buffer insert |
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| 148 | static inline void __buf_insert( channel(T) & chan, T & elem ) with(chan) { |
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[beeff61e] | 149 | memcpy( (void *)&buffer[back], (void *)&elem, sizeof(T) ); |
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[4a962d8] | 150 | count += 1; |
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| 151 | back++; |
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| 152 | if ( back == size ) back = 0; |
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| 153 | } |
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| 154 | |
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[a45e21c] | 155 | // needed to avoid an extra copy in closed case |
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| 156 | static inline bool __internal_try_insert( channel(T) & chan, T & elem ) with(chan) { |
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| 157 | lock( mutex_lock ); |
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| 158 | #ifdef CHAN_STATS |
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[88b49bb] | 159 | p_ops++; |
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[a45e21c] | 160 | #endif |
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[beeff61e] | 161 | |
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| 162 | ConsEmpty: if ( !cons`isEmpty ) { |
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| 163 | if ( !__handle_waituntil_OR( cons ) ) break ConsEmpty; |
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| 164 | __cons_handoff( chan, elem ); |
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| 165 | unlock( mutex_lock ); |
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| 166 | return true; |
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| 167 | } |
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| 168 | |
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[a45e21c] | 169 | if ( count == size ) { unlock( mutex_lock ); return false; } |
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[beeff61e] | 170 | |
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| 171 | __buf_insert( chan, elem ); |
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[a45e21c] | 172 | unlock( mutex_lock ); |
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| 173 | return true; |
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| 174 | } |
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| 175 | |
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| 176 | // attempts a nonblocking insert |
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| 177 | // returns true if insert was successful, false otherwise |
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| 178 | static inline bool try_insert( channel(T) & chan, T elem ) { return __internal_try_insert( chan, elem ); } |
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| 179 | |
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| 180 | // handles closed case of insert routine |
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| 181 | static inline void __closed_insert( channel(T) & chan, T & elem ) with(chan) { |
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[beeff61e] | 182 | channel_closed except{ &channel_closed_vt, &elem, &chan }; |
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[a45e21c] | 183 | throwResume except; // throw closed resumption |
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| 184 | if ( !__internal_try_insert( chan, elem ) ) throw except; // if try to insert fails (would block), throw termination |
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[d30e3eb] | 185 | } |
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[4a962d8] | 186 | |
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[42b739d7] | 187 | static inline void insert( channel(T) & chan, T elem ) with(chan) { |
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[a45e21c] | 188 | // check for close before acquire mx |
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| 189 | if ( unlikely(closed) ) { |
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| 190 | __closed_insert( chan, elem ); |
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| 191 | return; |
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| 192 | } |
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| 193 | |
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[4a962d8] | 194 | lock( mutex_lock ); |
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| 195 | |
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[a45e21c] | 196 | #ifdef CHAN_STATS |
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[88b49bb] | 197 | if ( !closed ) p_ops++; |
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[a45e21c] | 198 | #endif |
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| 199 | |
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| 200 | // if closed handle |
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| 201 | if ( unlikely(closed) ) { |
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| 202 | unlock( mutex_lock ); |
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| 203 | __closed_insert( chan, elem ); |
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| 204 | return; |
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| 205 | } |
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| 206 | |
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[beeff61e] | 207 | // buffer count must be zero if cons are blocked (also handles zero-size case) |
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| 208 | ConsEmpty: if ( !cons`isEmpty ) { |
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| 209 | if ( !__handle_waituntil_OR( cons ) ) break ConsEmpty; |
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| 210 | __cons_handoff( chan, elem ); |
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[5c931e0] | 211 | unlock( mutex_lock ); |
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[beeff61e] | 212 | return; |
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[5c931e0] | 213 | } |
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| 214 | |
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[4a962d8] | 215 | // wait if buffer is full, work will be completed by someone else |
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[d30e3eb] | 216 | if ( count == size ) { |
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[a45e21c] | 217 | #ifdef CHAN_STATS |
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[88b49bb] | 218 | p_blocks++; |
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[a45e21c] | 219 | #endif |
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| 220 | |
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| 221 | // check for if woken due to close |
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| 222 | if ( unlikely( block( prods, &elem, mutex_lock ) ) ) |
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| 223 | __closed_insert( chan, elem ); |
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[4a962d8] | 224 | return; |
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| 225 | } // if |
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| 226 | |
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[beeff61e] | 227 | __buf_insert( chan, elem ); |
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[4a962d8] | 228 | unlock( mutex_lock ); |
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[a45e21c] | 229 | } |
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[4a962d8] | 230 | |
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[a45e21c] | 231 | // does the buffer remove and potentially does waiting producer work |
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| 232 | static inline void __do_remove( channel(T) & chan, T & retval ) with(chan) { |
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[beeff61e] | 233 | memcpy( (void *)&retval, (void *)&buffer[front], sizeof(T) ); |
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| 234 | count -= 1; |
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| 235 | front = (front + 1) % size; |
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[d30e3eb] | 236 | if (count == size - 1 && !prods`isEmpty ) { |
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[beeff61e] | 237 | if ( !__handle_waituntil_OR( prods ) ) return; |
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| 238 | __buf_insert( chan, *(T *)prods`first.extra ); // do waiting producer work |
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[d30e3eb] | 239 | wake_one( prods ); |
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| 240 | } |
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[4a962d8] | 241 | } |
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[0e16a2d] | 242 | |
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[a45e21c] | 243 | // needed to avoid an extra copy in closed case and single return val case |
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| 244 | static inline bool __internal_try_remove( channel(T) & chan, T & retval ) with(chan) { |
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[0e16a2d] | 245 | lock( mutex_lock ); |
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[a45e21c] | 246 | #ifdef CHAN_STATS |
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[88b49bb] | 247 | c_ops++; |
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[a45e21c] | 248 | #endif |
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[beeff61e] | 249 | |
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| 250 | ZeroSize: if ( size == 0 && !prods`isEmpty ) { |
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| 251 | if ( !__handle_waituntil_OR( prods ) ) break ZeroSize; |
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| 252 | __prods_handoff( chan, retval ); |
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| 253 | unlock( mutex_lock ); |
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| 254 | return true; |
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| 255 | } |
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| 256 | |
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[a45e21c] | 257 | if ( count == 0 ) { unlock( mutex_lock ); return false; } |
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[beeff61e] | 258 | |
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[a45e21c] | 259 | __do_remove( chan, retval ); |
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[0e16a2d] | 260 | unlock( mutex_lock ); |
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[a45e21c] | 261 | return true; |
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[0e16a2d] | 262 | } |
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| 263 | |
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[a45e21c] | 264 | // attempts a nonblocking remove |
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| 265 | // returns [T, true] if insert was successful |
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| 266 | // returns [T, false] if insert was successful (T uninit) |
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| 267 | static inline [T, bool] try_remove( channel(T) & chan ) { |
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[0e16a2d] | 268 | T retval; |
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[beeff61e] | 269 | bool success = __internal_try_remove( chan, retval ); |
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| 270 | return [ retval, success ]; |
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[a45e21c] | 271 | } |
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[0e16a2d] | 272 | |
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[beeff61e] | 273 | static inline T try_remove( channel(T) & chan ) { |
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[a45e21c] | 274 | T retval; |
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| 275 | __internal_try_remove( chan, retval ); |
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[0e16a2d] | 276 | return retval; |
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| 277 | } |
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| 278 | |
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[a45e21c] | 279 | // handles closed case of insert routine |
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| 280 | static inline void __closed_remove( channel(T) & chan, T & retval ) with(chan) { |
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[beeff61e] | 281 | channel_closed except{ &channel_closed_vt, 0p, &chan }; |
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[a45e21c] | 282 | throwResume except; // throw resumption |
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| 283 | if ( !__internal_try_remove( chan, retval ) ) throw except; // if try to remove fails (would block), throw termination |
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[0e16a2d] | 284 | } |
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| 285 | |
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[a45e21c] | 286 | static inline T remove( channel(T) & chan ) with(chan) { |
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| 287 | T retval; |
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| 288 | if ( unlikely(closed) ) { |
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| 289 | __closed_remove( chan, retval ); |
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| 290 | return retval; |
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| 291 | } |
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| 292 | lock( mutex_lock ); |
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[0e16a2d] | 293 | |
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[a45e21c] | 294 | #ifdef CHAN_STATS |
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[88b49bb] | 295 | if ( !closed ) c_ops++; |
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[a45e21c] | 296 | #endif |
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[0e16a2d] | 297 | |
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[a45e21c] | 298 | if ( unlikely(closed) ) { |
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| 299 | unlock( mutex_lock ); |
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| 300 | __closed_remove( chan, retval ); |
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| 301 | return retval; |
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| 302 | } |
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[0e16a2d] | 303 | |
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[a45e21c] | 304 | // have to check for the zero size channel case |
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[beeff61e] | 305 | ZeroSize: if ( size == 0 && !prods`isEmpty ) { |
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| 306 | if ( !__handle_waituntil_OR( prods ) ) break ZeroSize; |
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| 307 | __prods_handoff( chan, retval ); |
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[a45e21c] | 308 | unlock( mutex_lock ); |
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| 309 | return retval; |
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| 310 | } |
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[0e16a2d] | 311 | |
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[a45e21c] | 312 | // wait if buffer is empty, work will be completed by someone else |
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[beeff61e] | 313 | if ( count == 0 ) { |
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[a45e21c] | 314 | #ifdef CHAN_STATS |
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[88b49bb] | 315 | c_blocks++; |
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[a45e21c] | 316 | #endif |
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| 317 | // check for if woken due to close |
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| 318 | if ( unlikely( block( cons, &retval, mutex_lock ) ) ) |
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| 319 | __closed_remove( chan, retval ); |
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| 320 | return retval; |
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| 321 | } |
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[0e16a2d] | 322 | |
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| 323 | // Remove from buffer |
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[a45e21c] | 324 | __do_remove( chan, retval ); |
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[0e16a2d] | 325 | unlock( mutex_lock ); |
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| 326 | return retval; |
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| 327 | } |
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[beeff61e] | 328 | |
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| 329 | /////////////////////////////////////////////////////////////////////////////////////////// |
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| 330 | // The following is support for waituntil (select) statements |
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| 331 | /////////////////////////////////////////////////////////////////////////////////////////// |
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| 332 | static inline bool unregister_chan( channel(T) & chan, select_node & node ) with(chan) { |
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[88b49bb] | 333 | if ( !node`isListed && !node.park_counter ) return false; // handle special OR case |
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[beeff61e] | 334 | lock( mutex_lock ); |
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| 335 | if ( node`isListed ) { // op wasn't performed |
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| 336 | remove( node ); |
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| 337 | unlock( mutex_lock ); |
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| 338 | return false; |
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| 339 | } |
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| 340 | unlock( mutex_lock ); |
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| 341 | |
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[00b046f] | 342 | // only return true when not special OR case and status is SAT |
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| 343 | return !node.park_counter ? false : *node.clause_status == __SELECT_SAT; |
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[beeff61e] | 344 | } |
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| 345 | |
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[6f774be] | 346 | // special case of __handle_waituntil_OR, that does some work to avoid starvation/deadlock case |
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| 347 | static inline bool __handle_pending( dlist( select_node ) & queue, select_node & mine ) { |
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| 348 | while ( !queue`isEmpty ) { |
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| 349 | // if node not a special OR case or if we win the special OR case race break |
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| 350 | if ( !queue`first.clause_status || queue`first.park_counter || __pending_set_other( queue`first, mine, ((unsigned long int)(&(queue`first))) ) ) |
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| 351 | return true; |
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| 352 | |
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| 353 | // our node lost the race when toggling in __pending_set_other |
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| 354 | if ( *mine.clause_status != __SELECT_PENDING ) |
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| 355 | return false; |
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| 356 | |
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| 357 | // otherwise we lost the special OR race so discard node |
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| 358 | try_pop_front( queue ); |
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| 359 | } |
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| 360 | return false; |
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| 361 | } |
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| 362 | |
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[beeff61e] | 363 | // type used by select statement to capture a chan read as the selected operation |
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| 364 | struct chan_read { |
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| 365 | T & ret; |
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[8607a72] | 366 | channel(T) & chan; |
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[beeff61e] | 367 | }; |
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| 368 | |
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| 369 | static inline void ?{}( chan_read(T) & cr, channel(T) & chan, T & ret ) { |
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| 370 | &cr.chan = &chan; |
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| 371 | &cr.ret = &ret; |
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| 372 | } |
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| 373 | static inline chan_read(T) ?<<?( T & ret, channel(T) & chan ) { chan_read(T) cr{ chan, ret }; return cr; } |
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| 374 | |
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| 375 | static inline void __handle_select_closed_read( chan_read(T) & this, select_node & node ) with(this.chan, this) { |
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| 376 | __closed_remove( chan, ret ); |
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| 377 | // if we get here then the insert succeeded |
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| 378 | __make_select_node_available( node ); |
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| 379 | } |
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| 380 | |
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| 381 | static inline bool register_select( chan_read(T) & this, select_node & node ) with(this.chan, this) { |
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| 382 | lock( mutex_lock ); |
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| 383 | node.extra = &ret; // set .extra so that if it == 0p later in on_selected it is due to channel close |
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| 384 | |
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| 385 | #ifdef CHAN_STATS |
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[88b49bb] | 386 | if ( !closed ) c_ops++; |
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[beeff61e] | 387 | #endif |
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| 388 | |
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[c4f411e] | 389 | if ( !node.park_counter ) { |
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| 390 | // are we special case OR and front of cons is also special case OR |
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| 391 | if ( !unlikely(closed) && !prods`isEmpty && prods`first.clause_status && !prods`first.park_counter ) { |
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| 392 | if ( !__make_select_node_pending( node ) ) { |
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| 393 | unlock( mutex_lock ); |
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| 394 | return false; |
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| 395 | } |
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[6f774be] | 396 | |
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| 397 | if ( __handle_pending( prods, node ) ) { |
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[c4f411e] | 398 | __prods_handoff( chan, ret ); |
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[629c95a] | 399 | __make_select_node_sat( node ); // need to to mark SAT now that we know operation is done or else threads could get stuck in __mark_select_node |
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[c4f411e] | 400 | unlock( mutex_lock ); |
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| 401 | return true; |
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| 402 | } |
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[6f774be] | 403 | if ( *node.clause_status == __SELECT_PENDING ) |
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| 404 | __make_select_node_unsat( node ); |
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[c4f411e] | 405 | } |
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| 406 | // check if we can complete operation. If so race to establish winner in special OR case |
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| 407 | if ( count != 0 || !prods`isEmpty || unlikely(closed) ) { |
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| 408 | if ( !__make_select_node_available( node ) ) { // we didn't win the race so give up on registering |
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| 409 | unlock( mutex_lock ); |
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| 410 | return false; |
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| 411 | } |
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[beeff61e] | 412 | } |
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| 413 | } |
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| 414 | |
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| 415 | if ( unlikely(closed) ) { |
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| 416 | unlock( mutex_lock ); |
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| 417 | __handle_select_closed_read( this, node ); |
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| 418 | return true; |
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| 419 | } |
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| 420 | |
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| 421 | // have to check for the zero size channel case |
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| 422 | ZeroSize: if ( size == 0 && !prods`isEmpty ) { |
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| 423 | if ( !__handle_waituntil_OR( prods ) ) break ZeroSize; |
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| 424 | __prods_handoff( chan, ret ); |
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| 425 | __set_avail_then_unlock( node, mutex_lock ); |
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| 426 | return true; |
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| 427 | } |
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| 428 | |
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| 429 | // wait if buffer is empty, work will be completed by someone else |
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| 430 | if ( count == 0 ) { |
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| 431 | #ifdef CHAN_STATS |
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[88b49bb] | 432 | c_blocks++; |
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[beeff61e] | 433 | #endif |
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| 434 | |
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| 435 | insert_last( cons, node ); |
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| 436 | unlock( mutex_lock ); |
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| 437 | return false; |
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| 438 | } |
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| 439 | |
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| 440 | // Remove from buffer |
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| 441 | __do_remove( chan, ret ); |
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| 442 | __set_avail_then_unlock( node, mutex_lock ); |
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| 443 | return true; |
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| 444 | } |
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| 445 | static inline bool unregister_select( chan_read(T) & this, select_node & node ) { return unregister_chan( this.chan, node ); } |
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[70a4ed5] | 446 | static inline void on_selected( chan_read(T) & this, select_node & node ) with(this) { |
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[beeff61e] | 447 | if ( node.extra == 0p ) // check if woken up due to closed channel |
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| 448 | __closed_remove( chan, ret ); |
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| 449 | // This is only reachable if not closed or closed exception was handled |
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| 450 | } |
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| 451 | |
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| 452 | // type used by select statement to capture a chan write as the selected operation |
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| 453 | struct chan_write { |
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| 454 | T elem; |
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[8607a72] | 455 | channel(T) & chan; |
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[beeff61e] | 456 | }; |
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| 457 | |
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| 458 | static inline void ?{}( chan_write(T) & cw, channel(T) & chan, T elem ) { |
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| 459 | &cw.chan = &chan; |
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| 460 | memcpy( (void *)&cw.elem, (void *)&elem, sizeof(T) ); |
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| 461 | } |
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| 462 | static inline chan_write(T) ?>>?( T elem, channel(T) & chan ) { chan_write(T) cw{ chan, elem }; return cw; } |
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| 463 | |
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| 464 | static inline void __handle_select_closed_write( chan_write(T) & this, select_node & node ) with(this.chan, this) { |
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| 465 | __closed_insert( chan, elem ); |
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| 466 | // if we get here then the insert succeeded |
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| 467 | __make_select_node_available( node ); |
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| 468 | } |
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| 469 | |
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| 470 | static inline bool register_select( chan_write(T) & this, select_node & node ) with(this.chan, this) { |
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| 471 | lock( mutex_lock ); |
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| 472 | node.extra = &elem; // set .extra so that if it == 0p later in on_selected it is due to channel close |
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| 473 | |
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| 474 | #ifdef CHAN_STATS |
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[88b49bb] | 475 | if ( !closed ) p_ops++; |
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[beeff61e] | 476 | #endif |
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| 477 | |
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[c4f411e] | 478 | // special OR case handling |
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| 479 | if ( !node.park_counter ) { |
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| 480 | // are we special case OR and front of cons is also special case OR |
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| 481 | if ( !unlikely(closed) && !cons`isEmpty && cons`first.clause_status && !cons`first.park_counter ) { |
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| 482 | if ( !__make_select_node_pending( node ) ) { |
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| 483 | unlock( mutex_lock ); |
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| 484 | return false; |
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| 485 | } |
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[6f774be] | 486 | |
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| 487 | if ( __handle_pending( cons, node ) ) { |
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[c4f411e] | 488 | __cons_handoff( chan, elem ); |
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[629c95a] | 489 | __make_select_node_sat( node ); // need to to mark SAT now that we know operation is done or else threads could get stuck in __mark_select_node |
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[c4f411e] | 490 | unlock( mutex_lock ); |
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| 491 | return true; |
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| 492 | } |
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[6f774be] | 493 | if ( *node.clause_status == __SELECT_PENDING ) |
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| 494 | __make_select_node_unsat( node ); |
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[c4f411e] | 495 | } |
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| 496 | // check if we can complete operation. If so race to establish winner in special OR case |
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| 497 | if ( count != size || !cons`isEmpty || unlikely(closed) ) { |
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| 498 | if ( !__make_select_node_available( node ) ) { // we didn't win the race so give up on registering |
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| 499 | unlock( mutex_lock ); |
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| 500 | return false; |
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| 501 | } |
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[beeff61e] | 502 | } |
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| 503 | } |
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| 504 | |
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| 505 | // if closed handle |
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| 506 | if ( unlikely(closed) ) { |
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| 507 | unlock( mutex_lock ); |
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| 508 | __handle_select_closed_write( this, node ); |
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| 509 | return true; |
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| 510 | } |
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| 511 | |
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| 512 | // handle blocked consumer case via handoff (buffer is implicitly empty) |
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| 513 | ConsEmpty: if ( !cons`isEmpty ) { |
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[cb69fba] | 514 | if ( !__handle_waituntil_OR( cons ) ) break ConsEmpty; |
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[beeff61e] | 515 | __cons_handoff( chan, elem ); |
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| 516 | __set_avail_then_unlock( node, mutex_lock ); |
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| 517 | return true; |
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| 518 | } |
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| 519 | |
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| 520 | // insert node in list if buffer is full, work will be completed by someone else |
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| 521 | if ( count == size ) { |
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| 522 | #ifdef CHAN_STATS |
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[88b49bb] | 523 | p_blocks++; |
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[beeff61e] | 524 | #endif |
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| 525 | |
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| 526 | insert_last( prods, node ); |
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| 527 | unlock( mutex_lock ); |
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| 528 | return false; |
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| 529 | } // if |
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| 530 | |
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| 531 | // otherwise carry out write either via normal insert |
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| 532 | __buf_insert( chan, elem ); |
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| 533 | __set_avail_then_unlock( node, mutex_lock ); |
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| 534 | return true; |
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| 535 | } |
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| 536 | static inline bool unregister_select( chan_write(T) & this, select_node & node ) { return unregister_chan( this.chan, node ); } |
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| 537 | |
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[70a4ed5] | 538 | static inline void on_selected( chan_write(T) & this, select_node & node ) with(this) { |
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[beeff61e] | 539 | if ( node.extra == 0p ) // check if woken up due to closed channel |
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| 540 | __closed_insert( chan, elem ); |
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| 541 | |
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| 542 | // This is only reachable if not closed or closed exception was handled |
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| 543 | } |
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| 544 | |
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[0e16a2d] | 545 | } // forall( T ) |
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[beeff61e] | 546 | |
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| 547 | |
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