source: libcfa/src/concurrency/locks.hfa@ f8a7fed

ADT arm-eh ast-experimental enum forall-pointer-decay jacob/cs343-translation new-ast-unique-expr pthread-emulation qualifiedEnum
Last change on this file since f8a7fed was 8f5576d5, checked in by Thierry Delisle <tdelisle@…>, 4 years ago

Missed a static inline
  • Property mode set to 100644
File size: 10.3 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) __attribute__((artificial));
42static inline bool P(Semaphore0nary & this, $thread * thrd) {
43 /* paranoid */ verify(!(thrd->seqable.next));
44 /* paranoid */ verify(!(thrd`next));
45
46 push(this.queue, thrd);
47 return true;
48}
49
50static inline bool P(Semaphore0nary & this) __attribute__((artificial));
51static inline bool P(Semaphore0nary & this) {
52 $thread * thrd = active_thread();
53 P(this, thrd);
54 park();
55 return true;
56}
57
58static inline $thread * V(Semaphore0nary & this, const bool doUnpark = true) __attribute__((artificial));
59static inline $thread * V(Semaphore0nary & this, const bool doUnpark = true) {
60 $thread * next;
61 lock(this.lock __cfaabi_dbg_ctx2);
62 for (;;) {
63 next = pop(this.queue);
64 if (next) break;
65 Pause();
66 }
67 unlock(this.lock);
68
69 if (doUnpark) unpark(next);
70 return next;
71}
72
73// Wrapper used on top of any sempahore to avoid potential locking
74struct BinaryBenaphore {
75 volatile ssize_t counter;
76};
77
78static inline {
79 void ?{}(BinaryBenaphore & this) { this.counter = 0; }
80 void ?{}(BinaryBenaphore & this, zero_t) { this.counter = 0; }
81 void ?{}(BinaryBenaphore & this, one_t ) { this.counter = 1; }
82
83 // returns true if no blocking needed
84 bool P(BinaryBenaphore & this) { return __atomic_fetch_sub(&this.counter, 1, __ATOMIC_SEQ_CST) > 0; }
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 P(ThreadBenaphore & this, $thread * t) { return /* P(this.ben) ? false : */ P(this.sem, t ); }
119static inline bool tryP(ThreadBenaphore & this) { return tryP(this.ben); }
120static inline bool P(ThreadBenaphore & this, bool wait) { return wait ? P(this) : tryP(this); }
121
122static inline $thread * V(ThreadBenaphore & this, const bool doUnpark = true) {
123 // if (V(this.ben)) return 0p;
124 return V(this.sem, doUnpark);
125}
126
127//-----------------------------------------------------------------------------
128// Semaphore
129struct semaphore {
130 __spinlock_t lock;
131 int count;
132 __queue_t($thread) waiting;
133};
134
135void ?{}(semaphore & this, int count = 1);
136void ^?{}(semaphore & this);
137bool P (semaphore & this);
138bool V (semaphore & this);
139bool V (semaphore & this, unsigned count);
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 void on_wait ( single_acquisition_lock & this ) { on_wait ( (blocking_lock &)this ); }
152static inline void on_notify ( single_acquisition_lock & this, struct $thread * t ) { on_notify( (blocking_lock &)this, t ); }
153static inline void set_recursion_count( single_acquisition_lock & this, size_t recursion ) { set_recursion_count( (blocking_lock &)this, recursion ); }
154static inline size_t get_recursion_count( single_acquisition_lock & this ) { return get_recursion_count( (blocking_lock &)this ); }
155
156//----------
157struct owner_lock {
158 inline blocking_lock;
159};
160
161static inline void ?{}( owner_lock & this ) {((blocking_lock &)this){ true, true };}
162static inline void ^?{}( owner_lock & this ) {}
163static inline void lock ( owner_lock & this ) { lock ( (blocking_lock &)this ); }
164static inline bool try_lock ( owner_lock & this ) { return try_lock( (blocking_lock &)this ); }
165static inline void unlock ( owner_lock & this ) { unlock ( (blocking_lock &)this ); }
166static inline void on_wait ( owner_lock & this ) { on_wait ( (blocking_lock &)this ); }
167static inline void on_notify( owner_lock & this, struct $thread * t ) { on_notify( (blocking_lock &)this, t ); }
168static inline void set_recursion_count( owner_lock & this, size_t recursion ) { set_recursion_count( (blocking_lock &)this, recursion ); }
169static inline size_t get_recursion_count( owner_lock & this ) { return get_recursion_count( (blocking_lock &)this ); }
170
171struct fast_lock {
172 $thread * volatile owner;
173 ThreadBenaphore sem;
174};
175
176static inline bool $try_lock(fast_lock & this, $thread * thrd) {
177 $thread * exp = 0p;
178 return __atomic_compare_exchange_n(&this.owner, &exp, thrd, false, __ATOMIC_SEQ_CST, __ATOMIC_RELAXED);
179}
180
181static inline void $lock(fast_lock & this, $thread * thrd) {
182 /* paranoid */verify(thrd != this.owner);
183
184 for (;;) {
185 if ($try_lock(this, thrd)) return;
186 P(this.sem, thrd);
187 }
188}
189
190static inline void lock( fast_lock & this ) {
191 $thread * thrd = active_thread();
192 /* paranoid */verify(thrd != this.owner);
193
194 for (;;) {
195 if ($try_lock(this, thrd)) return;
196 P(this.sem);
197 }
198}
199
200static inline void try_lock ( fast_lock & this ) {
201 $thread * thrd = active_thread();
202 /* paranoid */ verify(thrd != this.owner);
203 return $try_lock(this, thrd);
204}
205
206static inline void unlock( fast_lock & this ) {
207 $thread * thrd = active_thread();
208 /* paranoid */ verify(thrd == this.owner);
209 $thread * next = V(this.sem, false); // implicit fence
210 // open 'owner' only after fence
211 this.owner = 0p;
212
213 // Unpark the next person (can be 0p, unpark handles it)
214 unpark(next);
215}
216
217static inline void on_wait( fast_lock & this ) {
218 unlock(this);
219 #warning this is broken
220}
221
222static inline void on_notify( fast_lock & this, struct $thread * t ) {
223 $lock(this, t);
224 #warning this is broken
225}
226
227static inline void set_recursion_count( fast_lock & this, size_t recursion ) {}
228static inline size_t get_recursion_count( fast_lock & this ) { return 0; }
229
230struct mcs_node {
231 mcs_node * volatile next;
232 single_sem sem;
233};
234
235static inline void ?{}(mcs_node & this) { this.next = 0p; }
236
237static inline mcs_node * volatile & ?`next ( mcs_node * node ) {
238 return node->next;
239}
240
241struct mcs_lock {
242 mcs_queue(mcs_node) queue;
243};
244
245static inline void lock(mcs_lock & l, mcs_node & n) {
246 if(push(l.queue, &n))
247 wait(n.sem);
248}
249
250static inline void unlock(mcs_lock & l, mcs_node & n) {
251 mcs_node * next = advance(l.queue, &n);
252 if(next) post(next->sem);
253}
254
255//-----------------------------------------------------------------------------
256// is_blocking_lock
257trait is_blocking_lock(L & | sized(L)) {
258 // For synchronization locks to use when acquiring
259 void on_notify( L &, struct $thread * );
260
261 // For synchronization locks to use when releasing
262 void on_wait( L & );
263
264 // to get recursion count for cond lock to reset after waking
265 size_t get_recursion_count( L & );
266
267 // to set recursion count after getting signalled;
268 void set_recursion_count( L &, size_t recursion );
269};
270
271//-----------------------------------------------------------------------------
272// info_thread
273// the info thread is a wrapper around a thread used
274// to store extra data for use in the condition variable
275forall(L & | is_blocking_lock(L)) {
276 struct info_thread;
277
278 // for use by sequence
279 info_thread(L) *& Back( info_thread(L) * this );
280 info_thread(L) *& Next( info_thread(L) * this );
281}
282
283//-----------------------------------------------------------------------------
284// Synchronization Locks
285forall(L & | is_blocking_lock(L)) {
286 struct condition_variable {
287 // Spin lock used for mutual exclusion
288 __spinlock_t lock;
289
290 // List of blocked threads
291 Sequence( info_thread(L) ) blocked_threads;
292
293 // Count of current blocked threads
294 int count;
295 };
296
297 void ?{}( condition_variable(L) & this );
298 void ^?{}( condition_variable(L) & this );
299
300 bool notify_one( condition_variable(L) & this );
301 bool notify_all( condition_variable(L) & this );
302
303 uintptr_t front( condition_variable(L) & this );
304
305 bool empty ( condition_variable(L) & this );
306 int counter( condition_variable(L) & this );
307
308 void wait( condition_variable(L) & this );
309 void wait( condition_variable(L) & this, uintptr_t info );
310 bool wait( condition_variable(L) & this, Duration duration );
311 bool wait( condition_variable(L) & this, uintptr_t info, Duration duration );
312 bool wait( condition_variable(L) & this, Time time );
313 bool wait( condition_variable(L) & this, uintptr_t info, Time time );
314
315 void wait( condition_variable(L) & this, L & l );
316 void wait( condition_variable(L) & this, L & l, uintptr_t info );
317 bool wait( condition_variable(L) & this, L & l, Duration duration );
318 bool wait( condition_variable(L) & this, L & l, uintptr_t info, Duration duration );
319 bool wait( condition_variable(L) & this, L & l, Time time );
320 bool wait( condition_variable(L) & this, L & l, uintptr_t info, Time time );
321}
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