| 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 -- PUBLIC
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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 | #pragma once
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| 18 |
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| 19 | #include <stdbool.h>
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| 20 | #include <stdio.h>
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| 21 |
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| 22 | #include "bits/weakso_locks.hfa"
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| 23 | #include "containers/queueLockFree.hfa"
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| 24 | #include "containers/list.hfa"
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| 25 |
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| 26 | #include "limits.hfa"
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| 27 | #include "thread.hfa"
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| 28 |
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| 29 | #include "time_t.hfa"
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| 30 | #include "time.hfa"
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| 31 |
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| 32 | //-----------------------------------------------------------------------------
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| 33 | // Semaphore
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| 34 | struct semaphore {
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| 35 | __spinlock_t lock;
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| 36 | int count;
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| 37 | __queue_t(thread$) waiting;
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| 38 | };
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| 39 |
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| 40 | void ?{}(semaphore & this, int count = 1);
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| 41 | void ^?{}(semaphore & this);
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| 42 | bool P (semaphore & this);
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| 43 | bool V (semaphore & this);
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| 44 | bool V (semaphore & this, unsigned count);
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| 45 | thread$ * V (semaphore & this, bool );
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| 46 |
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| 47 | //----------
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| 48 | struct single_acquisition_lock {
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| 49 | inline blocking_lock;
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| 50 | };
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| 51 |
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| 52 | static inline void ?{}( single_acquisition_lock & this ) {((blocking_lock &)this){ false, false };}
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| 53 | static inline void ^?{}( single_acquisition_lock & this ) {}
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| 54 | static inline void lock ( single_acquisition_lock & this ) { lock ( (blocking_lock &)this ); }
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| 55 | static inline bool try_lock ( single_acquisition_lock & this ) { return try_lock( (blocking_lock &)this ); }
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| 56 | static inline void unlock ( single_acquisition_lock & this ) { unlock ( (blocking_lock &)this ); }
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| 57 | static inline size_t on_wait ( single_acquisition_lock & this ) { return on_wait ( (blocking_lock &)this ); }
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| 58 | static inline void on_wakeup( single_acquisition_lock & this, size_t v ) { on_wakeup ( (blocking_lock &)this, v ); }
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| 59 | static inline void on_notify( single_acquisition_lock & this, struct thread$ * t ) { on_notify( (blocking_lock &)this, t ); }
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| 60 |
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| 61 | //----------
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| 62 | struct owner_lock {
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| 63 | inline blocking_lock;
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| 64 | };
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| 65 |
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| 66 | static inline void ?{}( owner_lock & this ) {((blocking_lock &)this){ true, true };}
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| 67 | static inline void ^?{}( owner_lock & this ) {}
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| 68 | static inline void lock ( owner_lock & this ) { lock ( (blocking_lock &)this ); }
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| 69 | static inline bool try_lock ( owner_lock & this ) { return try_lock( (blocking_lock &)this ); }
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| 70 | static inline void unlock ( owner_lock & this ) { unlock ( (blocking_lock &)this ); }
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| 71 | static inline size_t on_wait ( owner_lock & this ) { return on_wait ( (blocking_lock &)this ); }
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| 72 | static inline void on_wakeup( owner_lock & this, size_t v ) { on_wakeup ( (blocking_lock &)this, v ); }
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| 73 | static inline void on_notify( owner_lock & this, struct thread$ * t ) { on_notify( (blocking_lock &)this, t ); }
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| 74 |
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| 75 | //-----------------------------------------------------------------------------
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| 76 | // MCS Lock
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| 77 | struct mcs_node {
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| 78 | mcs_node * volatile next;
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| 79 | single_sem sem;
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| 80 | };
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| 81 |
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| 82 | static inline void ?{}(mcs_node & this) { this.next = 0p; }
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| 83 |
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| 84 | static inline mcs_node * volatile & ?`next ( mcs_node * node ) {
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| 85 | return node->next;
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| 86 | }
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| 87 |
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| 88 | struct mcs_lock {
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| 89 | mcs_queue(mcs_node) queue;
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| 90 | };
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| 91 |
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| 92 | static inline void lock(mcs_lock & l, mcs_node & n) {
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| 93 | if(push(l.queue, &n))
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| 94 | wait(n.sem);
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| 95 | }
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| 96 |
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| 97 | static inline void unlock(mcs_lock & l, mcs_node & n) {
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| 98 | mcs_node * next = advance(l.queue, &n);
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| 99 | if(next) post(next->sem);
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| 100 | }
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| 101 |
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| 102 | //-----------------------------------------------------------------------------
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| 103 | // Linear backoff Spinlock
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| 104 | struct linear_backoff_then_block_lock {
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| 105 | // Spin lock used for mutual exclusion
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| 106 | __spinlock_t spinlock;
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| 107 |
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| 108 | // Current thread owning the lock
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| 109 | struct thread$ * owner;
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| 110 |
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| 111 | // List of blocked threads
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| 112 | dlist( thread$ ) blocked_threads;
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| 113 |
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| 114 | // Used for comparing and exchanging
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| 115 | volatile size_t lock_value;
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| 116 |
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| 117 | // used for linear backoff spinning
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| 118 | int spin_start;
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| 119 | int spin_end;
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| 120 | int spin_count;
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| 121 |
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| 122 | // after unsuccessful linear backoff yield this many times
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| 123 | int yield_count;
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| 124 | };
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| 125 |
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| 126 | static inline void ?{}( linear_backoff_then_block_lock & this, int spin_start, int spin_end, int spin_count, int yield_count ) {
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| 127 | this.spinlock{};
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| 128 | this.blocked_threads{};
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| 129 | this.lock_value = 0;
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| 130 | this.spin_start = spin_start;
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| 131 | this.spin_end = spin_end;
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| 132 | this.spin_count = spin_count;
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| 133 | this.yield_count = yield_count;
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| 134 | }
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| 135 | static inline void ?{}( linear_backoff_then_block_lock & this ) { this{4, 1024, 16, 0}; }
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| 136 | static inline void ^?{}( linear_backoff_then_block_lock & this ) {}
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| 137 | static inline void ?{}( linear_backoff_then_block_lock & this, linear_backoff_then_block_lock this2 ) = void;
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| 138 | static inline void ?=?( linear_backoff_then_block_lock & this, linear_backoff_then_block_lock this2 ) = void;
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| 139 |
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| 140 | static inline bool internal_try_lock(linear_backoff_then_block_lock & this, size_t & compare_val) with(this) {
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| 141 | if (__atomic_compare_exchange_n(&lock_value, &compare_val, 1, false, __ATOMIC_ACQUIRE, __ATOMIC_RELAXED)) {
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| 142 | owner = active_thread();
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| 143 | return true;
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| 144 | }
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| 145 | return false;
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| 146 | }
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| 147 |
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| 148 | static inline bool try_lock(linear_backoff_then_block_lock & this) { size_t compare_val = 0; return internal_try_lock(this, compare_val); }
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| 149 |
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| 150 | static inline bool try_lock_contention(linear_backoff_then_block_lock & this) with(this) {
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| 151 | if (__atomic_exchange_n(&lock_value, 2, __ATOMIC_ACQUIRE) == 0) {
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| 152 | owner = active_thread();
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| 153 | return true;
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| 154 | }
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| 155 | return false;
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| 156 | }
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| 157 |
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| 158 | static inline bool block(linear_backoff_then_block_lock & this) with(this) {
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| 159 | lock( spinlock __cfaabi_dbg_ctx2 );
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| 160 | if (lock_value != 2) {
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| 161 | unlock( spinlock );
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| 162 | return true;
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| 163 | }
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| 164 | insert_last( blocked_threads, *active_thread() );
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| 165 | unlock( spinlock );
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| 166 | park( );
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| 167 | return true;
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| 168 | }
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| 169 |
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| 170 | static inline void lock(linear_backoff_then_block_lock & this) with(this) {
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| 171 | // if owner just return
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| 172 | if (active_thread() == owner) return;
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| 173 | size_t compare_val = 0;
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| 174 | int spin = spin_start;
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| 175 | // linear backoff
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| 176 | for( ;; ) {
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| 177 | compare_val = 0;
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| 178 | if (internal_try_lock(this, compare_val)) return;
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| 179 | if (2 == compare_val) break;
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| 180 | for (int i = 0; i < spin; i++) Pause();
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| 181 | if (spin >= spin_end) break;
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| 182 | spin += spin;
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| 183 | }
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| 184 |
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| 185 | if(2 != compare_val && try_lock_contention(this)) return;
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| 186 | // block until signalled
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| 187 | while (block(this)) if(try_lock_contention(this)) return;
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| 188 | }
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| 189 |
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| 190 | static inline void unlock(linear_backoff_then_block_lock & this) with(this) {
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| 191 | verify(lock_value > 0);
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| 192 | owner = 0p;
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| 193 | if (__atomic_exchange_n(&lock_value, 0, __ATOMIC_RELEASE) == 1) return;
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| 194 | lock( spinlock __cfaabi_dbg_ctx2 );
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| 195 | thread$ * t = &try_pop_front( blocked_threads );
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| 196 | unlock( spinlock );
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| 197 | unpark( t );
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| 198 | }
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| 199 |
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| 200 | static inline void on_notify(linear_backoff_then_block_lock & this, struct thread$ * t ) { unpark(t); }
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| 201 | static inline size_t on_wait(linear_backoff_then_block_lock & this) { unlock(this); return 0; }
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| 202 | static inline void on_wakeup(linear_backoff_then_block_lock & this, size_t recursion ) { lock(this); }
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| 203 |
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| 204 | //-----------------------------------------------------------------------------
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| 205 | // Fast Block Lock
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| 206 |
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| 207 | // High efficiency minimal blocking lock
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| 208 | // - No reacquire for cond var
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| 209 | // - No recursive acquisition
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| 210 | // - No ownership
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| 211 | struct fast_block_lock {
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| 212 | // Spin lock used for mutual exclusion
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| 213 | __spinlock_t lock;
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| 214 |
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| 215 | // List of blocked threads
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| 216 | dlist( thread$ ) blocked_threads;
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| 217 |
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| 218 | bool held:1;
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| 219 | };
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| 220 |
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| 221 | static inline void ?{}( fast_block_lock & this ) with(this) {
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| 222 | lock{};
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| 223 | blocked_threads{};
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| 224 | held = false;
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| 225 | }
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| 226 | static inline void ^?{}( fast_block_lock & this ) {}
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| 227 | static inline void ?{}( fast_block_lock & this, fast_block_lock this2 ) = void;
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| 228 | static inline void ?=?( fast_block_lock & this, fast_block_lock this2 ) = void;
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| 229 |
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| 230 | // if this is called recursively IT WILL DEADLOCK!!!!!
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| 231 | static inline void lock(fast_block_lock & this) with(this) {
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| 232 | lock( lock __cfaabi_dbg_ctx2 );
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| 233 | if (held) {
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| 234 | insert_last( blocked_threads, *active_thread() );
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| 235 | unlock( lock );
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| 236 | park( );
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| 237 | return;
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| 238 | }
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| 239 | held = true;
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| 240 | unlock( lock );
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| 241 | }
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| 242 |
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| 243 | static inline void unlock(fast_block_lock & this) with(this) {
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| 244 | lock( lock __cfaabi_dbg_ctx2 );
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| 245 | /* paranoid */ verifyf( held != false, "Attempt to release lock %p that isn't held", &this );
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| 246 | thread$ * t = &try_pop_front( blocked_threads );
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| 247 | held = ( t ? true : false );
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| 248 | unpark( t );
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| 249 | unlock( lock );
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| 250 | }
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| 251 |
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| 252 | static inline void on_notify(fast_block_lock & this, struct thread$ * t ) { unpark(t); }
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| 253 | static inline size_t on_wait(fast_block_lock & this) { unlock(this); return 0; }
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| 254 | static inline void on_wakeup(fast_block_lock & this, size_t recursion ) { }
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| 255 |
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| 256 | //-----------------------------------------------------------------------------
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| 257 | // is_blocking_lock
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| 258 | trait is_blocking_lock(L & | sized(L)) {
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| 259 | // For synchronization locks to use when acquiring
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| 260 | void on_notify( L &, struct thread$ * );
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| 261 |
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| 262 | // For synchronization locks to use when releasing
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| 263 | size_t on_wait( L & );
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| 264 |
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| 265 | // to set recursion count after getting signalled;
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| 266 | void on_wakeup( L &, size_t recursion );
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| 267 | };
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| 268 |
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| 269 | //-----------------------------------------------------------------------------
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| 270 | // // info_thread
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| 271 | // // the info thread is a wrapper around a thread used
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| 272 | // // to store extra data for use in the condition variable
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| 273 | forall(L & | is_blocking_lock(L)) {
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| 274 | struct info_thread;
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| 275 |
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| 276 | // // for use by sequence
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| 277 | // info_thread(L) *& Back( info_thread(L) * this );
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| 278 | // info_thread(L) *& Next( info_thread(L) * this );
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| 279 | }
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| 280 |
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| 281 | //-----------------------------------------------------------------------------
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| 282 | // Synchronization Locks
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| 283 | forall(L & | is_blocking_lock(L)) {
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| 284 |
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| 285 | //-----------------------------------------------------------------------------
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| 286 | // condition_variable
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| 287 |
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| 288 | // The multi-tool condition variable
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| 289 | // - can pass timeouts to wait for either a signal or timeout
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| 290 | // - can wait without passing a lock
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| 291 | // - can have waiters reacquire different locks while waiting on the same cond var
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| 292 | // - has shadow queue
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| 293 | // - can be signalled outside of critical sections with no locks held
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| 294 | struct condition_variable {
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| 295 | // Spin lock used for mutual exclusion
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| 296 | __spinlock_t lock;
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| 297 |
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| 298 | // List of blocked threads
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| 299 | dlist( info_thread(L) ) blocked_threads;
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| 300 |
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| 301 | // Count of current blocked threads
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| 302 | int count;
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| 303 | };
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| 304 |
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| 305 |
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| 306 | void ?{}( condition_variable(L) & this );
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| 307 | void ^?{}( condition_variable(L) & this );
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| 308 |
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| 309 | bool notify_one( condition_variable(L) & this );
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| 310 | bool notify_all( condition_variable(L) & this );
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| 311 |
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| 312 | uintptr_t front( condition_variable(L) & this );
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| 313 |
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| 314 | bool empty ( condition_variable(L) & this );
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| 315 | int counter( condition_variable(L) & this );
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| 316 |
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| 317 | void wait( condition_variable(L) & this );
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| 318 | void wait( condition_variable(L) & this, uintptr_t info );
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| 319 | bool wait( condition_variable(L) & this, Duration duration );
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| 320 | bool wait( condition_variable(L) & this, uintptr_t info, Duration duration );
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| 321 |
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| 322 | void wait( condition_variable(L) & this, L & l );
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| 323 | void wait( condition_variable(L) & this, L & l, uintptr_t info );
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| 324 | bool wait( condition_variable(L) & this, L & l, Duration duration );
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| 325 | bool wait( condition_variable(L) & this, L & l, uintptr_t info, Duration duration );
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| 326 |
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| 327 | //-----------------------------------------------------------------------------
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| 328 | // fast_cond_var
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| 329 |
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| 330 | // The trimmed and slim condition variable
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| 331 | // - no internal lock so you must hold a lock while using this cond var
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| 332 | // - signalling without holding branded lock is UNSAFE!
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| 333 | // - only allows usage of one lock, cond var is branded after usage
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| 334 | struct fast_cond_var {
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| 335 | // List of blocked threads
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| 336 | dlist( info_thread(L) ) blocked_threads;
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| 337 |
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| 338 | #ifdef __CFA_DEBUG__
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| 339 | L * lock_used;
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| 340 | #endif
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| 341 | };
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| 342 |
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| 343 |
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| 344 | void ?{}( fast_cond_var(L) & this );
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| 345 | void ^?{}( fast_cond_var(L) & this );
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| 346 |
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| 347 | bool notify_one( fast_cond_var(L) & this );
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| 348 | bool notify_all( fast_cond_var(L) & this );
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| 349 |
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| 350 | uintptr_t front( fast_cond_var(L) & this );
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| 351 |
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| 352 | bool empty ( fast_cond_var(L) & this );
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| 353 |
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| 354 | void wait( fast_cond_var(L) & this, L & l );
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| 355 | void wait( fast_cond_var(L) & this, L & l, uintptr_t info );
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| 356 | }
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