1 |
|
/* |
2 |
|
* Written by Doug Lea with assistance from members of JCP JSR-166 |
3 |
|
* Expert Group and released to the public domain, as explained at |
4 |
< |
* http://creativecommons.org/licenses/publicdomain |
4 |
> |
* http://creativecommons.org/publicdomain/zero/1.0/ |
5 |
|
*/ |
6 |
|
|
7 |
|
package jsr166y; |
17 |
|
* {@link java.util.concurrent.CountDownLatch CountDownLatch} |
18 |
|
* but supporting more flexible usage. |
19 |
|
* |
20 |
< |
* <p> <b>Registration.</b> Unlike the case for other barriers, the |
20 |
> |
* <p><b>Registration.</b> Unlike the case for other barriers, the |
21 |
|
* number of parties <em>registered</em> to synchronize on a phaser |
22 |
|
* may vary over time. Tasks may be registered at any time (using |
23 |
|
* methods {@link #register}, {@link #bulkRegister}, or forms of |
30 |
|
* (However, you can introduce such bookkeeping by subclassing this |
31 |
|
* class.) |
32 |
|
* |
33 |
< |
* <p> <b>Synchronization.</b> Like a {@code CyclicBarrier}, a {@code |
33 |
> |
* <p><b>Synchronization.</b> Like a {@code CyclicBarrier}, a {@code |
34 |
|
* Phaser} may be repeatedly awaited. Method {@link |
35 |
|
* #arriveAndAwaitAdvance} has effect analogous to {@link |
36 |
|
* java.util.concurrent.CyclicBarrier#await CyclicBarrier.await}. Each |
44 |
|
* |
45 |
|
* <ul> |
46 |
|
* |
47 |
< |
* <li> <b>Arrival.</b> Methods {@link #arrive} and |
47 |
> |
* <li><b>Arrival.</b> Methods {@link #arrive} and |
48 |
|
* {@link #arriveAndDeregister} record arrival. These methods |
49 |
|
* do not block, but return an associated <em>arrival phase |
50 |
|
* number</em>; that is, the phase number of the phaser to which |
57 |
|
* flexible than, providing a barrier action to a {@code |
58 |
|
* CyclicBarrier}. |
59 |
|
* |
60 |
< |
* <li> <b>Waiting.</b> Method {@link #awaitAdvance} requires an |
60 |
> |
* <li><b>Waiting.</b> Method {@link #awaitAdvance} requires an |
61 |
|
* argument indicating an arrival phase number, and returns when |
62 |
|
* the phaser advances to (or is already at) a different phase. |
63 |
|
* Unlike similar constructions using {@code CyclicBarrier}, |
74 |
|
* |
75 |
|
* </ul> |
76 |
|
* |
77 |
< |
* <p> <b>Termination.</b> A phaser may enter a <em>termination</em> |
77 |
> |
* <p><b>Termination.</b> A phaser may enter a <em>termination</em> |
78 |
|
* state, that may be checked using method {@link #isTerminated}. Upon |
79 |
|
* termination, all synchronization methods immediately return without |
80 |
< |
* waiting for advance, as indicated by a negative return |
81 |
< |
* value. Similarly, attempts to register upon termination have no |
82 |
< |
* effect. Termination is triggered when an invocation of {@code |
83 |
< |
* onAdvance} returns {@code true}. The default implementation returns |
84 |
< |
* {@code true} if a deregistration has caused the number of |
85 |
< |
* registered parties to become zero. As illustrated below, when |
86 |
< |
* phasers control actions with a fixed number of iterations, it is |
87 |
< |
* often convenient to override this method to cause termination when |
88 |
< |
* the current phase number reaches a threshold. Method {@link |
89 |
< |
* #forceTermination} is also available to abruptly release waiting |
90 |
< |
* threads and allow them to terminate. |
80 |
> |
* waiting for advance, as indicated by a negative return value. |
81 |
> |
* Similarly, attempts to register upon termination have no effect. |
82 |
> |
* Termination is triggered when an invocation of {@code onAdvance} |
83 |
> |
* returns {@code true}. The default implementation returns {@code |
84 |
> |
* true} if a deregistration has caused the number of registered |
85 |
> |
* parties to become zero. As illustrated below, when phasers control |
86 |
> |
* actions with a fixed number of iterations, it is often convenient |
87 |
> |
* to override this method to cause termination when the current phase |
88 |
> |
* number reaches a threshold. Method {@link #forceTermination} is |
89 |
> |
* also available to abruptly release waiting threads and allow them |
90 |
> |
* to terminate. |
91 |
|
* |
92 |
< |
* <p> <b>Tiering.</b> Phasers may be <em>tiered</em> (i.e., |
92 |
> |
* <p><b>Tiering.</b> Phasers may be <em>tiered</em> (i.e., |
93 |
|
* constructed in tree structures) to reduce contention. Phasers with |
94 |
|
* large numbers of parties that would otherwise experience heavy |
95 |
|
* synchronization contention costs may instead be set up so that |
130 |
|
* void runTasks(List<Runnable> tasks) { |
131 |
|
* final Phaser phaser = new Phaser(1); // "1" to register self |
132 |
|
* // create and start threads |
133 |
< |
* for (Runnable task : tasks) { |
133 |
> |
* for (final Runnable task : tasks) { |
134 |
|
* phaser.register(); |
135 |
|
* new Thread() { |
136 |
|
* public void run() { |
193 |
|
* phaser.arriveAndDeregister(); |
194 |
|
* }}</pre> |
195 |
|
* |
196 |
– |
* |
196 |
|
* <p>To create a set of {@code n} tasks using a tree of phasers, you |
197 |
|
* could use code of the following form, assuming a Task class with a |
198 |
|
* constructor accepting a {@code Phaser} that it registers with upon |
236 |
|
*/ |
237 |
|
|
238 |
|
/** |
239 |
< |
* Primary state representation, holding four fields: |
239 |
> |
* Primary state representation, holding four bit-fields: |
240 |
|
* |
241 |
< |
* * unarrived -- the number of parties yet to hit barrier (bits 0-15) |
242 |
< |
* * parties -- the number of parties to wait (bits 16-31) |
243 |
< |
* * phase -- the generation of the barrier (bits 32-62) |
244 |
< |
* * terminated -- set if barrier is terminated (bit 63 / sign) |
241 |
> |
* unarrived -- the number of parties yet to hit barrier (bits 0-15) |
242 |
> |
* parties -- the number of parties to wait (bits 16-31) |
243 |
> |
* phase -- the generation of the barrier (bits 32-62) |
244 |
> |
* terminated -- set if barrier is terminated (bit 63 / sign) |
245 |
|
* |
246 |
|
* Except that a phaser with no registered parties is |
247 |
< |
* distinguished with the otherwise illegal state of having zero |
247 |
> |
* distinguished by the otherwise illegal state of having zero |
248 |
|
* parties and one unarrived parties (encoded as EMPTY below). |
249 |
|
* |
250 |
|
* To efficiently maintain atomicity, these values are packed into |
259 |
|
* parent. |
260 |
|
* |
261 |
|
* The phase of a subphaser is allowed to lag that of its |
262 |
< |
* ancestors until it is actually accessed. Method reconcileState |
263 |
< |
* is usually attempted only only when the number of unarrived |
265 |
< |
* parties appears to be zero, which indicates a potential lag in |
266 |
< |
* updating phase after the root advanced. |
262 |
> |
* ancestors until it is actually accessed -- see method |
263 |
> |
* reconcileState. |
264 |
|
*/ |
265 |
|
private volatile long state; |
266 |
|
|
267 |
|
private static final int MAX_PARTIES = 0xffff; |
268 |
< |
private static final int MAX_PHASE = 0x7fffffff; |
268 |
> |
private static final int MAX_PHASE = Integer.MAX_VALUE; |
269 |
|
private static final int PARTIES_SHIFT = 16; |
270 |
|
private static final int PHASE_SHIFT = 32; |
271 |
|
private static final int UNARRIVED_MASK = 0xffff; // to mask ints |
272 |
|
private static final long PARTIES_MASK = 0xffff0000L; // to mask longs |
273 |
+ |
private static final long COUNTS_MASK = 0xffffffffL; |
274 |
|
private static final long TERMINATION_BIT = 1L << 63; |
275 |
|
|
276 |
|
// some special values |
277 |
|
private static final int ONE_ARRIVAL = 1; |
278 |
|
private static final int ONE_PARTY = 1 << PARTIES_SHIFT; |
279 |
+ |
private static final int ONE_DEREGISTER = ONE_ARRIVAL|ONE_PARTY; |
280 |
|
private static final int EMPTY = 1; |
281 |
|
|
282 |
|
// The following unpacking methods are usually manually inlined |
283 |
|
|
284 |
|
private static int unarrivedOf(long s) { |
285 |
|
int counts = (int)s; |
286 |
< |
return (counts == EMPTY) ? 0 : counts & UNARRIVED_MASK; |
286 |
> |
return (counts == EMPTY) ? 0 : (counts & UNARRIVED_MASK); |
287 |
|
} |
288 |
|
|
289 |
|
private static int partiesOf(long s) { |
291 |
|
} |
292 |
|
|
293 |
|
private static int phaseOf(long s) { |
294 |
< |
return (int) (s >>> PHASE_SHIFT); |
294 |
> |
return (int)(s >>> PHASE_SHIFT); |
295 |
|
} |
296 |
|
|
297 |
|
private static int arrivedOf(long s) { |
344 |
|
* Manually tuned to speed up and minimize race windows for the |
345 |
|
* common case of just decrementing unarrived field. |
346 |
|
* |
347 |
< |
* @param deregister false for arrive, true for arriveAndDeregister |
347 |
> |
* @param adjust value to subtract from state; |
348 |
> |
* ONE_ARRIVAL for arrive, |
349 |
> |
* ONE_DEREGISTER for arriveAndDeregister |
350 |
|
*/ |
351 |
< |
private int doArrive(boolean deregister) { |
351 |
< |
int adj = deregister ? ONE_ARRIVAL|ONE_PARTY : ONE_ARRIVAL; |
351 |
> |
private int doArrive(int adjust) { |
352 |
|
final Phaser root = this.root; |
353 |
|
for (;;) { |
354 |
|
long s = (root == this) ? state : reconcileState(); |
355 |
|
int phase = (int)(s >>> PHASE_SHIFT); |
356 |
– |
int counts = (int)s; |
357 |
– |
int unarrived = (counts & UNARRIVED_MASK) - 1; |
356 |
|
if (phase < 0) |
357 |
|
return phase; |
358 |
< |
else if (counts == EMPTY || unarrived < 0) { |
359 |
< |
if (root == this || reconcileState() == s) |
360 |
< |
throw new IllegalStateException(badArrive(s)); |
361 |
< |
} |
362 |
< |
else if (UNSAFE.compareAndSwapLong(this, stateOffset, s, s-=adj)) { |
363 |
< |
if (unarrived == 0) { |
358 |
> |
int counts = (int)s; |
359 |
> |
int unarrived = (counts == EMPTY) ? 0 : (counts & UNARRIVED_MASK); |
360 |
> |
if (unarrived <= 0) |
361 |
> |
throw new IllegalStateException(badArrive(s)); |
362 |
> |
if (UNSAFE.compareAndSwapLong(this, stateOffset, s, s-=adjust)) { |
363 |
> |
if (unarrived == 1) { |
364 |
|
long n = s & PARTIES_MASK; // base of next state |
365 |
< |
int nextUnarrived = ((int)n) >>> PARTIES_SHIFT; |
366 |
< |
if (root != this) |
367 |
< |
return parent.doArrive(nextUnarrived == 0); |
368 |
< |
if (onAdvance(phase, nextUnarrived)) |
369 |
< |
n |= TERMINATION_BIT; |
370 |
< |
else if (nextUnarrived == 0) |
371 |
< |
n |= EMPTY; |
365 |
> |
int nextUnarrived = (int)n >>> PARTIES_SHIFT; |
366 |
> |
if (root == this) { |
367 |
> |
if (onAdvance(phase, nextUnarrived)) |
368 |
> |
n |= TERMINATION_BIT; |
369 |
> |
else if (nextUnarrived == 0) |
370 |
> |
n |= EMPTY; |
371 |
> |
else |
372 |
> |
n |= nextUnarrived; |
373 |
> |
int nextPhase = (phase + 1) & MAX_PHASE; |
374 |
> |
n |= (long)nextPhase << PHASE_SHIFT; |
375 |
> |
UNSAFE.compareAndSwapLong(this, stateOffset, s, n); |
376 |
> |
releaseWaiters(phase); |
377 |
> |
} |
378 |
> |
else if (nextUnarrived == 0) { // propagate deregistration |
379 |
> |
phase = parent.doArrive(ONE_DEREGISTER); |
380 |
> |
UNSAFE.compareAndSwapLong(this, stateOffset, |
381 |
> |
s, s | EMPTY); |
382 |
> |
} |
383 |
|
else |
384 |
< |
n |= nextUnarrived; |
376 |
< |
n |= ((long)((phase + 1) & MAX_PHASE)) << PHASE_SHIFT; |
377 |
< |
UNSAFE.compareAndSwapLong(this, stateOffset, s, n); |
378 |
< |
releaseWaiters(phase); |
384 |
> |
phase = parent.doArrive(ONE_ARRIVAL); |
385 |
|
} |
386 |
|
return phase; |
387 |
|
} |
396 |
|
*/ |
397 |
|
private int doRegister(int registrations) { |
398 |
|
// adjustment to state |
399 |
< |
long adj = ((long)registrations << PARTIES_SHIFT) | registrations; |
400 |
< |
Phaser par = parent; |
399 |
> |
long adjust = ((long)registrations << PARTIES_SHIFT) | registrations; |
400 |
> |
final Phaser parent = this.parent; |
401 |
|
int phase; |
402 |
|
for (;;) { |
403 |
< |
long s = state; |
403 |
> |
long s = (parent == null) ? state : reconcileState(); |
404 |
|
int counts = (int)s; |
405 |
|
int parties = counts >>> PARTIES_SHIFT; |
406 |
|
int unarrived = counts & UNARRIVED_MASK; |
407 |
|
if (registrations > MAX_PARTIES - parties) |
408 |
|
throw new IllegalStateException(badRegister(s)); |
409 |
< |
else if ((phase = (int)(s >>> PHASE_SHIFT)) < 0) |
409 |
> |
phase = (int)(s >>> PHASE_SHIFT); |
410 |
> |
if (phase < 0) |
411 |
|
break; |
412 |
< |
else if (counts != EMPTY) { // not 1st registration |
413 |
< |
if (par == null || reconcileState() == s) { |
412 |
> |
if (counts != EMPTY) { // not 1st registration |
413 |
> |
if (parent == null || reconcileState() == s) { |
414 |
|
if (unarrived == 0) // wait out advance |
415 |
|
root.internalAwaitAdvance(phase, null); |
416 |
|
else if (UNSAFE.compareAndSwapLong(this, stateOffset, |
417 |
< |
s, s + adj)) |
417 |
> |
s, s + adjust)) |
418 |
|
break; |
419 |
|
} |
420 |
|
} |
421 |
< |
else if (par == null) { // 1st root registration |
422 |
< |
long next = (((long) phase) << PHASE_SHIFT) | adj; |
421 |
> |
else if (parent == null) { // 1st root registration |
422 |
> |
long next = ((long)phase << PHASE_SHIFT) | adjust; |
423 |
|
if (UNSAFE.compareAndSwapLong(this, stateOffset, s, next)) |
424 |
|
break; |
425 |
|
} |
426 |
|
else { |
427 |
|
synchronized (this) { // 1st sub registration |
428 |
|
if (state == s) { // recheck under lock |
429 |
< |
par.doRegister(1); |
430 |
< |
do { // force current phase |
429 |
> |
phase = parent.doRegister(1); |
430 |
> |
if (phase < 0) |
431 |
> |
break; |
432 |
> |
// finish registration whenever parent registration |
433 |
> |
// succeeded, even when racing with termination, |
434 |
> |
// since these are part of the same "transaction". |
435 |
> |
while (!UNSAFE.compareAndSwapLong |
436 |
> |
(this, stateOffset, s, |
437 |
> |
((long)phase << PHASE_SHIFT) | adjust)) { |
438 |
> |
s = state; |
439 |
|
phase = (int)(root.state >>> PHASE_SHIFT); |
440 |
< |
// assert phase < 0 || (int)state == EMPTY; |
441 |
< |
} while (!UNSAFE.compareAndSwapLong |
427 |
< |
(this, stateOffset, state, |
428 |
< |
(((long) phase) << PHASE_SHIFT) | adj)); |
440 |
> |
// assert (int)s == EMPTY; |
441 |
> |
} |
442 |
|
break; |
443 |
|
} |
444 |
|
} |
449 |
|
|
450 |
|
/** |
451 |
|
* Resolves lagged phase propagation from root if necessary. |
452 |
+ |
* Reconciliation normally occurs when root has advanced but |
453 |
+ |
* subphasers have not yet done so, in which case they must finish |
454 |
+ |
* their own advance by setting unarrived to parties (or if |
455 |
+ |
* parties is zero, resetting to unregistered EMPTY state). |
456 |
+ |
* |
457 |
+ |
* @return reconciled state |
458 |
|
*/ |
459 |
|
private long reconcileState() { |
460 |
< |
Phaser rt = root; |
460 |
> |
final Phaser root = this.root; |
461 |
|
long s = state; |
462 |
< |
if (rt != this) { |
463 |
< |
int phase; |
464 |
< |
while ((phase = (int)(rt.state >>> PHASE_SHIFT)) != |
465 |
< |
(int)(s >>> PHASE_SHIFT)) { |
466 |
< |
// assert phase < 0 || unarrivedOf(s) == 0 |
467 |
< |
long t; // to reread s |
468 |
< |
long p = s & PARTIES_MASK; // unshifted parties field |
469 |
< |
long n = (((long) phase) << PHASE_SHIFT) | p; |
470 |
< |
if (phase >= 0) { |
471 |
< |
if (p == 0L) |
472 |
< |
n |= EMPTY; // reset to empty |
473 |
< |
else |
455 |
< |
n |= p >>> PARTIES_SHIFT; // set unarr to parties |
456 |
< |
} |
457 |
< |
if ((t = state) == s && |
458 |
< |
UNSAFE.compareAndSwapLong(this, stateOffset, s, s = n)) |
459 |
< |
break; |
460 |
< |
s = t; |
461 |
< |
} |
462 |
> |
if (root != this) { |
463 |
> |
int phase, p; |
464 |
> |
// CAS to root phase with current parties, tripping unarrived |
465 |
> |
while ((phase = (int)(root.state >>> PHASE_SHIFT)) != |
466 |
> |
(int)(s >>> PHASE_SHIFT) && |
467 |
> |
!UNSAFE.compareAndSwapLong |
468 |
> |
(this, stateOffset, s, |
469 |
> |
s = (((long)phase << PHASE_SHIFT) | |
470 |
> |
((phase < 0) ? (s & COUNTS_MASK) : |
471 |
> |
(((p = (int)s >>> PARTIES_SHIFT) == 0) ? EMPTY : |
472 |
> |
((s & PARTIES_MASK) | p)))))) |
473 |
> |
s = state; |
474 |
|
} |
475 |
|
return s; |
476 |
|
} |
536 |
|
this.evenQ = new AtomicReference<QNode>(); |
537 |
|
this.oddQ = new AtomicReference<QNode>(); |
538 |
|
} |
539 |
< |
this.state = (parties == 0) ? (long) EMPTY : |
540 |
< |
((((long) phase) << PHASE_SHIFT) | |
541 |
< |
(((long) parties) << PARTIES_SHIFT) | |
542 |
< |
((long) parties)); |
539 |
> |
this.state = (parties == 0) ? (long)EMPTY : |
540 |
> |
((long)phase << PHASE_SHIFT) | |
541 |
> |
((long)parties << PARTIES_SHIFT) | |
542 |
> |
((long)parties); |
543 |
|
} |
544 |
|
|
545 |
|
/** |
553 |
|
* |
554 |
|
* @return the arrival phase number to which this registration |
555 |
|
* applied. If this value is negative, then this phaser has |
556 |
< |
* terminated, in which casem registration has no effect. |
556 |
> |
* terminated, in which case registration has no effect. |
557 |
|
* @throws IllegalStateException if attempting to register more |
558 |
|
* than the maximum supported number of parties |
559 |
|
*/ |
575 |
|
* advance to the next phase |
576 |
|
* @return the arrival phase number to which this registration |
577 |
|
* applied. If this value is negative, then this phaser has |
578 |
< |
* terminated, in which casem registration has no effect. |
578 |
> |
* terminated, in which case registration has no effect. |
579 |
|
* @throws IllegalStateException if attempting to register more |
580 |
|
* than the maximum supported number of parties |
581 |
|
* @throws IllegalArgumentException if {@code parties < 0} |
601 |
|
* of unarrived parties would become negative |
602 |
|
*/ |
603 |
|
public int arrive() { |
604 |
< |
return doArrive(false); |
604 |
> |
return doArrive(ONE_ARRIVAL); |
605 |
|
} |
606 |
|
|
607 |
|
/** |
621 |
|
* of registered or unarrived parties would become negative |
622 |
|
*/ |
623 |
|
public int arriveAndDeregister() { |
624 |
< |
return doArrive(true); |
624 |
> |
return doArrive(ONE_DEREGISTER); |
625 |
|
} |
626 |
|
|
627 |
|
/** |
648 |
|
for (;;) { |
649 |
|
long s = (root == this) ? state : reconcileState(); |
650 |
|
int phase = (int)(s >>> PHASE_SHIFT); |
639 |
– |
int counts = (int)s; |
640 |
– |
int unarrived = (counts & UNARRIVED_MASK) - 1; |
651 |
|
if (phase < 0) |
652 |
|
return phase; |
653 |
< |
else if (counts == EMPTY || unarrived < 0) { |
654 |
< |
if (reconcileState() == s) |
655 |
< |
throw new IllegalStateException(badArrive(s)); |
656 |
< |
} |
657 |
< |
else if (UNSAFE.compareAndSwapLong(this, stateOffset, s, |
658 |
< |
s -= ONE_ARRIVAL)) { |
659 |
< |
if (unarrived != 0) |
653 |
> |
int counts = (int)s; |
654 |
> |
int unarrived = (counts == EMPTY) ? 0 : (counts & UNARRIVED_MASK); |
655 |
> |
if (unarrived <= 0) |
656 |
> |
throw new IllegalStateException(badArrive(s)); |
657 |
> |
if (UNSAFE.compareAndSwapLong(this, stateOffset, s, |
658 |
> |
s -= ONE_ARRIVAL)) { |
659 |
> |
if (unarrived > 1) |
660 |
|
return root.internalAwaitAdvance(phase, null); |
661 |
|
if (root != this) |
662 |
|
return parent.arriveAndAwaitAdvance(); |
663 |
|
long n = s & PARTIES_MASK; // base of next state |
664 |
< |
int nextUnarrived = ((int)n) >>> PARTIES_SHIFT; |
664 |
> |
int nextUnarrived = (int)n >>> PARTIES_SHIFT; |
665 |
|
if (onAdvance(phase, nextUnarrived)) |
666 |
|
n |= TERMINATION_BIT; |
667 |
|
else if (nextUnarrived == 0) |
692 |
|
*/ |
693 |
|
public int awaitAdvance(int phase) { |
694 |
|
final Phaser root = this.root; |
695 |
< |
int p = (int)((root == this? state : reconcileState()) >>> PHASE_SHIFT); |
695 |
> |
long s = (root == this) ? state : reconcileState(); |
696 |
> |
int p = (int)(s >>> PHASE_SHIFT); |
697 |
|
if (phase < 0) |
698 |
|
return phase; |
699 |
|
if (p == phase) |
719 |
|
public int awaitAdvanceInterruptibly(int phase) |
720 |
|
throws InterruptedException { |
721 |
|
final Phaser root = this.root; |
722 |
< |
int p = (int)((root == this? state : reconcileState()) >>> PHASE_SHIFT); |
722 |
> |
long s = (root == this) ? state : reconcileState(); |
723 |
> |
int p = (int)(s >>> PHASE_SHIFT); |
724 |
|
if (phase < 0) |
725 |
|
return phase; |
726 |
|
if (p == phase) { |
757 |
|
throws InterruptedException, TimeoutException { |
758 |
|
long nanos = unit.toNanos(timeout); |
759 |
|
final Phaser root = this.root; |
760 |
< |
int p = (int)((root == this? state : reconcileState()) >>> PHASE_SHIFT); |
760 |
> |
long s = (root == this) ? state : reconcileState(); |
761 |
> |
int p = (int)(s >>> PHASE_SHIFT); |
762 |
|
if (phase < 0) |
763 |
|
return phase; |
764 |
|
if (p == phase) { |
786 |
|
final Phaser root = this.root; |
787 |
|
long s; |
788 |
|
while ((s = root.state) >= 0) { |
789 |
< |
long next = (s & ~((long)UNARRIVED_MASK)) | TERMINATION_BIT; |
790 |
< |
if (UNSAFE.compareAndSwapLong(root, stateOffset, s, next)) { |
789 |
> |
if (UNSAFE.compareAndSwapLong(root, stateOffset, |
790 |
> |
s, s | TERMINATION_BIT)) { |
791 |
|
// signal all threads |
792 |
< |
releaseWaiters(0); |
793 |
< |
releaseWaiters(1); |
792 |
> |
releaseWaiters(0); // Waiters on evenQ |
793 |
> |
releaseWaiters(1); // Waiters on oddQ |
794 |
|
return; |
795 |
|
} |
796 |
|
} |
820 |
|
|
821 |
|
/** |
822 |
|
* Returns the number of registered parties that have arrived at |
823 |
< |
* the current phase of this phaser. |
823 |
> |
* the current phase of this phaser. If this phaser has terminated, |
824 |
> |
* the returned value is meaningless and arbitrary. |
825 |
|
* |
826 |
|
* @return the number of arrived parties |
827 |
|
*/ |
831 |
|
|
832 |
|
/** |
833 |
|
* Returns the number of registered parties that have not yet |
834 |
< |
* arrived at the current phase of this phaser. |
834 |
> |
* arrived at the current phase of this phaser. If this phaser has |
835 |
> |
* terminated, the returned value is meaningless and arbitrary. |
836 |
|
* |
837 |
|
* @return the number of unarrived parties |
838 |
|
*/ |
996 |
|
|
997 |
|
/** |
998 |
|
* Possibly blocks and waits for phase to advance unless aborted. |
999 |
< |
* Call only from root node. |
999 |
> |
* Call only on root phaser. |
1000 |
|
* |
1001 |
|
* @param phase current phase |
1002 |
|
* @param node if non-null, the wait node to track interrupt and timeout; |
1004 |
|
* @return current phase |
1005 |
|
*/ |
1006 |
|
private int internalAwaitAdvance(int phase, QNode node) { |
1007 |
+ |
// assert root == this; |
1008 |
|
releaseWaiters(phase-1); // ensure old queue clean |
1009 |
|
boolean queued = false; // true when node is enqueued |
1010 |
|
int lastUnarrived = 0; // to increase spins upon change |
1118 |
|
|
1119 |
|
// Unsafe mechanics |
1120 |
|
|
1121 |
< |
private static final sun.misc.Unsafe UNSAFE = getUnsafe(); |
1122 |
< |
private static final long stateOffset = |
1123 |
< |
objectFieldOffset("state", Phaser.class); |
1108 |
< |
|
1109 |
< |
private static long objectFieldOffset(String field, Class<?> klazz) { |
1121 |
> |
private static final sun.misc.Unsafe UNSAFE; |
1122 |
> |
private static final long stateOffset; |
1123 |
> |
static { |
1124 |
|
try { |
1125 |
< |
return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field)); |
1126 |
< |
} catch (NoSuchFieldException e) { |
1127 |
< |
// Convert Exception to corresponding Error |
1128 |
< |
NoSuchFieldError error = new NoSuchFieldError(field); |
1129 |
< |
error.initCause(e); |
1130 |
< |
throw error; |
1125 |
> |
UNSAFE = getUnsafe(); |
1126 |
> |
Class<?> k = Phaser.class; |
1127 |
> |
stateOffset = UNSAFE.objectFieldOffset |
1128 |
> |
(k.getDeclaredField("state")); |
1129 |
> |
} catch (Exception e) { |
1130 |
> |
throw new Error(e); |
1131 |
|
} |
1132 |
|
} |
1133 |
|
|
1141 |
|
private static sun.misc.Unsafe getUnsafe() { |
1142 |
|
try { |
1143 |
|
return sun.misc.Unsafe.getUnsafe(); |
1144 |
< |
} catch (SecurityException se) { |
1145 |
< |
try { |
1146 |
< |
return java.security.AccessController.doPrivileged |
1147 |
< |
(new java.security |
1148 |
< |
.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
1149 |
< |
public sun.misc.Unsafe run() throws Exception { |
1150 |
< |
java.lang.reflect.Field f = sun.misc |
1151 |
< |
.Unsafe.class.getDeclaredField("theUnsafe"); |
1152 |
< |
f.setAccessible(true); |
1153 |
< |
return (sun.misc.Unsafe) f.get(null); |
1154 |
< |
}}); |
1155 |
< |
} catch (java.security.PrivilegedActionException e) { |
1156 |
< |
throw new RuntimeException("Could not initialize intrinsics", |
1157 |
< |
e.getCause()); |
1158 |
< |
} |
1144 |
> |
} catch (SecurityException tryReflectionInstead) {} |
1145 |
> |
try { |
1146 |
> |
return java.security.AccessController.doPrivileged |
1147 |
> |
(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
1148 |
> |
public sun.misc.Unsafe run() throws Exception { |
1149 |
> |
Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class; |
1150 |
> |
for (java.lang.reflect.Field f : k.getDeclaredFields()) { |
1151 |
> |
f.setAccessible(true); |
1152 |
> |
Object x = f.get(null); |
1153 |
> |
if (k.isInstance(x)) |
1154 |
> |
return k.cast(x); |
1155 |
> |
} |
1156 |
> |
throw new NoSuchFieldError("the Unsafe"); |
1157 |
> |
}}); |
1158 |
> |
} catch (java.security.PrivilegedActionException e) { |
1159 |
> |
throw new RuntimeException("Could not initialize intrinsics", |
1160 |
> |
e.getCause()); |
1161 |
|
} |
1162 |
|
} |
1163 |
|
} |