source: libcfa/src/concurrency/locks.hfa @ ddd473f

arm-ehjacob/cs343-translationnew-ast-unique-expr
Last change on this file since ddd473f was ddd473f, checked in by Thierry Delisle <tdelisle@…>, 6 months ago

Fix a copy/paste mistake and removed a warning in nodebug

  • Property mode set to 100644
File size: 9.5 KB
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1//
2// Cforall Version 1.0.0 Copyright (C) 2021 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// locks.hfa -- PUBLIC
8// Runtime locks that used with the runtime thread system.
9//
10// Author           : Colby Alexander Parsons
11// Created On       : Thu Jan 21 19:46:50 2021
12// Last Modified By :
13// Last Modified On :
14// Update Count     :
15//
16
17#pragma once
18
19#include <stdbool.h>
20
21#include "bits/weakso_locks.hfa"
22#include "containers/queueLockFree.hfa"
23
24#include "thread.hfa"
25
26#include "time_t.hfa"
27#include "time.hfa"
28
29//-----------------------------------------------------------------------------
30// Semaphores
31
32// '0-nary' semaphore
33// Similar to a counting semaphore except the value of one is never reached
34// as a consequence, a V() that would bring the value to 1 *spins* until
35// a P consumes it
36struct Semaphore0nary {
37        __spinlock_t lock; // needed to protect
38        mpsc_queue($thread) queue;
39};
40
41static inline bool P(Semaphore0nary & this, $thread * thrd) {
42        /* paranoid */ verify(!(thrd->seqable.next));
43        /* paranoid */ verify(!(thrd`next));
44
45        push(this.queue, thrd);
46        return true;
47}
48
49static inline bool P(Semaphore0nary & this) {
50    $thread * thrd = active_thread();
51    P(this, thrd);
52    park();
53    return true;
54}
55
56static inline $thread * V(Semaphore0nary & this, bool doUnpark = true) {
57        $thread * next;
58        lock(this.lock __cfaabi_dbg_ctx2);
59                for (;;) {
60                        next = pop(this.queue);
61                        if (next) break;
62                        Pause();
63                }
64        unlock(this.lock);
65
66        if (doUnpark) unpark(next);
67        return next;
68}
69
70// Wrapper used on top of any sempahore to avoid potential locking
71struct BinaryBenaphore {
72        volatile ssize_t counter;
73};
74
75static inline {
76        void ?{}(BinaryBenaphore & this) { this.counter = 0; }
77        void ?{}(BinaryBenaphore & this, zero_t) { this.counter = 0; }
78        void ?{}(BinaryBenaphore & this, one_t ) { this.counter = 1; }
79
80        // returns true if no blocking needed
81        bool P(BinaryBenaphore & this) {
82                return __atomic_fetch_sub(&this.counter, 1, __ATOMIC_SEQ_CST) > 0;
83        }
84
85        bool tryP(BinaryBenaphore & this) {
86                ssize_t c = this.counter;
87                return (c >= 1) && __atomic_compare_exchange_n(&this.counter, &c, c-1, false, __ATOMIC_SEQ_CST, __ATOMIC_RELAXED);
88        }
89
90        // returns true if notify needed
91        bool V(BinaryBenaphore & this) {
92                ssize_t c = 0;
93                for () {
94                        if (__atomic_compare_exchange_n(&this.counter, &c, c+1, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)) {
95                                if (c == 0) return true;
96                                /* paranoid */ verify(c < 0);
97                                return false;
98                        } else {
99                                if (c == 1) return true;
100                                /* paranoid */ verify(c < 1);
101                                Pause();
102                        }
103                }
104        }
105}
106
107// Binary Semaphore based on the BinaryBenaphore on top of the 0-nary Semaphore
108struct ThreadBenaphore {
109        BinaryBenaphore ben;
110        Semaphore0nary  sem;
111};
112
113static inline void ?{}(ThreadBenaphore & this) {}
114static inline void ?{}(ThreadBenaphore & this, zero_t) { (this.ben){ 0 }; }
115static inline void ?{}(ThreadBenaphore & this, one_t ) { (this.ben){ 1 }; }
116
117static inline bool P(ThreadBenaphore & this)              { return P(this.ben) ? false : P(this.sem); }
118static inline bool tryP(ThreadBenaphore & this)           { return tryP(this.ben); }
119static inline bool P(ThreadBenaphore & this, bool wait)   { return wait ? P(this) : tryP(this); }
120
121static inline $thread * V(ThreadBenaphore & this, bool doUnpark = true) {
122        if (V(this.ben)) return 0p;
123        return V(this.sem, doUnpark);
124}
125
126//-----------------------------------------------------------------------------
127// Semaphore
128struct semaphore {
129        __spinlock_t lock;
130        int count;
131        __queue_t($thread) waiting;
132};
133
134void  ?{}(semaphore & this, int count = 1);
135void ^?{}(semaphore & this);
136bool   P (semaphore & this);
137bool   V (semaphore & this);
138bool   V (semaphore & this, unsigned count);
139$thread * V (semaphore & this, bool );
140
141//----------
142struct single_acquisition_lock {
143        inline blocking_lock;
144};
145
146static inline void  ?{}( single_acquisition_lock & this ) {((blocking_lock &)this){ false, false };}
147static inline void ^?{}( single_acquisition_lock & this ) {}
148static inline void   lock     ( single_acquisition_lock & this ) { lock    ( (blocking_lock &)this ); }
149static inline bool   try_lock ( single_acquisition_lock & this ) { return try_lock( (blocking_lock &)this ); }
150static inline void   unlock   ( single_acquisition_lock & this ) { unlock  ( (blocking_lock &)this ); }
151static inline size_t on_wait  ( single_acquisition_lock & this ) { return on_wait ( (blocking_lock &)this ); }
152static inline void   on_wakeup( single_acquisition_lock & this, size_t v ) { on_wakeup ( (blocking_lock &)this, v ); }
153static inline void   on_notify( single_acquisition_lock & this, struct $thread * t ) { on_notify( (blocking_lock &)this, t ); }
154
155//----------
156struct owner_lock {
157        inline blocking_lock;
158};
159
160static inline void  ?{}( owner_lock & this ) {((blocking_lock &)this){ true, true };}
161static inline void ^?{}( owner_lock & this ) {}
162static inline void   lock     ( owner_lock & this ) { lock    ( (blocking_lock &)this ); }
163static inline bool   try_lock ( owner_lock & this ) { return try_lock( (blocking_lock &)this ); }
164static inline void   unlock   ( owner_lock & this ) { unlock  ( (blocking_lock &)this ); }
165static inline size_t on_wait  ( owner_lock & this ) { return on_wait ( (blocking_lock &)this ); }
166static inline void   on_wakeup( owner_lock & this, size_t v ) { on_wakeup ( (blocking_lock &)this, v ); }
167static inline void   on_notify( owner_lock & this, struct $thread * t ) { on_notify( (blocking_lock &)this, t ); }
168
169struct fast_lock {
170        $thread * volatile owner;
171        ThreadBenaphore sem;
172};
173
174static inline bool $try_lock(fast_lock & this, $thread * thrd) {
175    $thread * exp = 0p;
176    return __atomic_compare_exchange_n(&this.owner, &exp, thrd, false, __ATOMIC_SEQ_CST, __ATOMIC_RELAXED);
177}
178
179static inline void lock( fast_lock & this ) __attribute__((artificial));
180static inline void lock( fast_lock & this ) {
181        $thread * thrd = active_thread();
182        /* paranoid */verify(thrd != this.owner);
183
184        for (;;) {
185                if ($try_lock(this, thrd)) return;
186                P(this.sem);
187        }
188}
189
190static inline bool try_lock( fast_lock & this ) __attribute__((artificial));
191static inline bool try_lock ( fast_lock & this ) {
192        $thread * thrd = active_thread();
193        /* paranoid */ verify(thrd != this.owner);
194        return $try_lock(this, thrd);
195}
196
197static inline $thread * unlock( fast_lock & this ) __attribute__((artificial));
198static inline $thread * unlock( fast_lock & this ) {
199        /* paranoid */ verify(active_thread() == this.owner);
200
201        // open 'owner' before unlocking anyone
202        // so new and unlocked threads don't park incorrectly.
203        // This may require additional fencing on ARM.
204        this.owner = 0p;
205
206        return V(this.sem);
207}
208
209static inline size_t on_wait( fast_lock & this ) { unlock(this); return 0; }
210static inline void on_wakeup( fast_lock & this, size_t ) { lock(this); }
211static inline void on_notify( fast_lock &, struct $thread * t ) { unpark(t); }
212
213struct mcs_node {
214        mcs_node * volatile next;
215        single_sem sem;
216};
217
218static inline void ?{}(mcs_node & this) { this.next = 0p; }
219
220static inline mcs_node * volatile & ?`next ( mcs_node * node ) {
221        return node->next;
222}
223
224struct mcs_lock {
225        mcs_queue(mcs_node) queue;
226};
227
228static inline void lock(mcs_lock & l, mcs_node & n) {
229        if(push(l.queue, &n))
230                wait(n.sem);
231}
232
233static inline void unlock(mcs_lock & l, mcs_node & n) {
234        mcs_node * next = advance(l.queue, &n);
235        if(next) post(next->sem);
236}
237
238//-----------------------------------------------------------------------------
239// is_blocking_lock
240trait is_blocking_lock(L & | sized(L)) {
241        // For synchronization locks to use when acquiring
242        void on_notify( L &, struct $thread * );
243
244        // For synchronization locks to use when releasing
245        size_t on_wait( L & );
246
247        // to set recursion count after getting signalled;
248        void on_wakeup( L &, size_t recursion );
249};
250
251//-----------------------------------------------------------------------------
252// info_thread
253// the info thread is a wrapper around a thread used
254// to store extra data for use in the condition variable
255forall(L & | is_blocking_lock(L)) {
256        struct info_thread;
257
258        // for use by sequence
259        info_thread(L) *& Back( info_thread(L) * this );
260        info_thread(L) *& Next( info_thread(L) * this );
261}
262
263//-----------------------------------------------------------------------------
264// Synchronization Locks
265forall(L & | is_blocking_lock(L)) {
266        struct condition_variable {
267                // Spin lock used for mutual exclusion
268                __spinlock_t lock;
269
270                // List of blocked threads
271                Sequence( info_thread(L) ) blocked_threads;
272
273                // Count of current blocked threads
274                int count;
275        };
276
277        void  ?{}( condition_variable(L) & this );
278        void ^?{}( condition_variable(L) & this );
279
280        bool notify_one( condition_variable(L) & this );
281        bool notify_all( condition_variable(L) & this );
282
283        uintptr_t front( condition_variable(L) & this );
284
285        bool empty  ( condition_variable(L) & this );
286        int  counter( condition_variable(L) & this );
287
288        void wait( condition_variable(L) & this );
289        void wait( condition_variable(L) & this, uintptr_t info );
290        bool wait( condition_variable(L) & this, Duration duration );
291        bool wait( condition_variable(L) & this, uintptr_t info, Duration duration );
292        bool wait( condition_variable(L) & this, Time time );
293        bool wait( condition_variable(L) & this, uintptr_t info, Time time );
294
295        void wait( condition_variable(L) & this, L & l );
296        void wait( condition_variable(L) & this, L & l, uintptr_t info );
297        bool wait( condition_variable(L) & this, L & l, Duration duration );
298        bool wait( condition_variable(L) & this, L & l, uintptr_t info, Duration duration );
299        bool wait( condition_variable(L) & this, L & l, Time time );
300        bool wait( condition_variable(L) & this, L & l, uintptr_t info, Time time );
301}
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