271 |
|
private static final int PHASE_SHIFT = 32; |
272 |
|
private static final int UNARRIVED_MASK = 0xffff; // to mask ints |
273 |
|
private static final long PARTIES_MASK = 0xffff0000L; // to mask longs |
274 |
+ |
private static final long COUNTS_MASK = 0xffffffffL; |
275 |
|
private static final long TERMINATION_BIT = 1L << 63; |
276 |
|
|
277 |
|
// some special values |
278 |
|
private static final int ONE_ARRIVAL = 1; |
279 |
|
private static final int ONE_PARTY = 1 << PARTIES_SHIFT; |
280 |
+ |
private static final int ONE_DEREGISTER = ONE_ARRIVAL|ONE_PARTY; |
281 |
|
private static final int EMPTY = 1; |
282 |
|
|
283 |
|
// The following unpacking methods are usually manually inlined |
284 |
|
|
285 |
|
private static int unarrivedOf(long s) { |
286 |
|
int counts = (int)s; |
287 |
< |
return (counts == EMPTY) ? 0 : counts & UNARRIVED_MASK; |
287 |
> |
return (counts == EMPTY) ? 0 : (counts & UNARRIVED_MASK); |
288 |
|
} |
289 |
|
|
290 |
|
private static int partiesOf(long s) { |
345 |
|
* Manually tuned to speed up and minimize race windows for the |
346 |
|
* common case of just decrementing unarrived field. |
347 |
|
* |
348 |
< |
* @param deregister false for arrive, true for arriveAndDeregister |
348 |
> |
* @param adjust value to subtract from state; |
349 |
> |
* ONE_ARRIVAL for arrive, |
350 |
> |
* ONE_DEREGISTER for arriveAndDeregister |
351 |
|
*/ |
352 |
< |
private int doArrive(boolean deregister) { |
349 |
< |
int adj = deregister ? ONE_ARRIVAL|ONE_PARTY : ONE_ARRIVAL; |
352 |
> |
private int doArrive(int adjust) { |
353 |
|
final Phaser root = this.root; |
354 |
|
for (;;) { |
355 |
|
long s = (root == this) ? state : reconcileState(); |
356 |
|
int phase = (int)(s >>> PHASE_SHIFT); |
354 |
– |
int counts = (int)s; |
355 |
– |
int unarrived = (counts & UNARRIVED_MASK) - 1; |
357 |
|
if (phase < 0) |
358 |
|
return phase; |
359 |
< |
else if (counts == EMPTY || unarrived < 0) { |
360 |
< |
if (root == this || reconcileState() == s) |
361 |
< |
throw new IllegalStateException(badArrive(s)); |
362 |
< |
} |
363 |
< |
else if (UNSAFE.compareAndSwapLong(this, stateOffset, s, s-=adj)) { |
364 |
< |
if (unarrived == 0) { |
359 |
> |
int counts = (int)s; |
360 |
> |
int unarrived = (counts == EMPTY) ? 0 : (counts & UNARRIVED_MASK); |
361 |
> |
if (unarrived <= 0) |
362 |
> |
throw new IllegalStateException(badArrive(s)); |
363 |
> |
if (UNSAFE.compareAndSwapLong(this, stateOffset, s, s-=adjust)) { |
364 |
> |
if (unarrived == 1) { |
365 |
|
long n = s & PARTIES_MASK; // base of next state |
366 |
|
int nextUnarrived = (int)n >>> PARTIES_SHIFT; |
367 |
< |
if (root != this) |
368 |
< |
return parent.doArrive(nextUnarrived == 0); |
369 |
< |
if (onAdvance(phase, nextUnarrived)) |
370 |
< |
n |= TERMINATION_BIT; |
371 |
< |
else if (nextUnarrived == 0) |
372 |
< |
n |= EMPTY; |
367 |
> |
if (root == this) { |
368 |
> |
if (onAdvance(phase, nextUnarrived)) |
369 |
> |
n |= TERMINATION_BIT; |
370 |
> |
else if (nextUnarrived == 0) |
371 |
> |
n |= EMPTY; |
372 |
> |
else |
373 |
> |
n |= nextUnarrived; |
374 |
> |
int nextPhase = (phase + 1) & MAX_PHASE; |
375 |
> |
n |= (long)nextPhase << PHASE_SHIFT; |
376 |
> |
UNSAFE.compareAndSwapLong(this, stateOffset, s, n); |
377 |
> |
releaseWaiters(phase); |
378 |
> |
} |
379 |
> |
else if (nextUnarrived == 0) { // propagate deregistration |
380 |
> |
phase = parent.doArrive(ONE_DEREGISTER); |
381 |
> |
UNSAFE.compareAndSwapLong(this, stateOffset, |
382 |
> |
s, s | EMPTY); |
383 |
> |
} |
384 |
|
else |
385 |
< |
n |= nextUnarrived; |
374 |
< |
n |= (long)((phase + 1) & MAX_PHASE) << PHASE_SHIFT; |
375 |
< |
UNSAFE.compareAndSwapLong(this, stateOffset, s, n); |
376 |
< |
releaseWaiters(phase); |
385 |
> |
phase = parent.doArrive(ONE_ARRIVAL); |
386 |
|
} |
387 |
|
return phase; |
388 |
|
} |
397 |
|
*/ |
398 |
|
private int doRegister(int registrations) { |
399 |
|
// adjustment to state |
400 |
< |
long adj = ((long)registrations << PARTIES_SHIFT) | registrations; |
400 |
> |
long adjust = ((long)registrations << PARTIES_SHIFT) | registrations; |
401 |
|
final Phaser parent = this.parent; |
402 |
|
int phase; |
403 |
|
for (;;) { |
404 |
< |
long s = state; |
404 |
> |
long s = (parent == null) ? state : reconcileState(); |
405 |
|
int counts = (int)s; |
406 |
|
int parties = counts >>> PARTIES_SHIFT; |
407 |
|
int unarrived = counts & UNARRIVED_MASK; |
408 |
|
if (registrations > MAX_PARTIES - parties) |
409 |
|
throw new IllegalStateException(badRegister(s)); |
410 |
< |
else if ((phase = (int)(s >>> PHASE_SHIFT)) < 0) |
410 |
> |
phase = (int)(s >>> PHASE_SHIFT); |
411 |
> |
if (phase < 0) |
412 |
|
break; |
413 |
< |
else if (counts != EMPTY) { // not 1st registration |
413 |
> |
if (counts != EMPTY) { // not 1st registration |
414 |
|
if (parent == null || reconcileState() == s) { |
415 |
|
if (unarrived == 0) // wait out advance |
416 |
|
root.internalAwaitAdvance(phase, null); |
417 |
|
else if (UNSAFE.compareAndSwapLong(this, stateOffset, |
418 |
< |
s, s + adj)) |
418 |
> |
s, s + adjust)) |
419 |
|
break; |
420 |
|
} |
421 |
|
} |
422 |
|
else if (parent == null) { // 1st root registration |
423 |
< |
long next = ((long)phase << PHASE_SHIFT) | adj; |
423 |
> |
long next = ((long)phase << PHASE_SHIFT) | adjust; |
424 |
|
if (UNSAFE.compareAndSwapLong(this, stateOffset, s, next)) |
425 |
|
break; |
426 |
|
} |
427 |
|
else { |
428 |
|
synchronized (this) { // 1st sub registration |
429 |
|
if (state == s) { // recheck under lock |
430 |
< |
parent.doRegister(1); |
431 |
< |
do { // force current phase |
430 |
> |
phase = parent.doRegister(1); |
431 |
> |
if (phase < 0) |
432 |
> |
break; |
433 |
> |
// finish registration whenever parent registration |
434 |
> |
// succeeded, even when racing with termination, |
435 |
> |
// since these are part of the same "transaction". |
436 |
> |
while (!UNSAFE.compareAndSwapLong |
437 |
> |
(this, stateOffset, s, |
438 |
> |
((long)phase << PHASE_SHIFT) | adjust)) { |
439 |
> |
s = state; |
440 |
|
phase = (int)(root.state >>> PHASE_SHIFT); |
441 |
< |
// assert phase < 0 || (int)state == EMPTY; |
442 |
< |
} while (!UNSAFE.compareAndSwapLong |
425 |
< |
(this, stateOffset, state, |
426 |
< |
((long)phase << PHASE_SHIFT) | adj)); |
441 |
> |
// assert (int)s == EMPTY; |
442 |
> |
} |
443 |
|
break; |
444 |
|
} |
445 |
|
} |
454 |
|
* subphasers have not yet done so, in which case they must finish |
455 |
|
* their own advance by setting unarrived to parties (or if |
456 |
|
* parties is zero, resetting to unregistered EMPTY state). |
441 |
– |
* However, this method may also be called when "floating" |
442 |
– |
* subphasers with possibly some unarrived parties are merely |
443 |
– |
* catching up to current phase, in which case counts are |
444 |
– |
* unaffected. |
457 |
|
* |
458 |
|
* @return reconciled state |
459 |
|
*/ |
461 |
|
final Phaser root = this.root; |
462 |
|
long s = state; |
463 |
|
if (root != this) { |
464 |
< |
int phase, u, p; |
465 |
< |
// CAS root phase with current parties; possibly trip unarrived |
464 |
> |
int phase, p; |
465 |
> |
// CAS to root phase with current parties, tripping unarrived |
466 |
|
while ((phase = (int)(root.state >>> PHASE_SHIFT)) != |
467 |
|
(int)(s >>> PHASE_SHIFT) && |
468 |
|
!UNSAFE.compareAndSwapLong |
469 |
|
(this, stateOffset, s, |
470 |
|
s = (((long)phase << PHASE_SHIFT) | |
471 |
< |
(s & PARTIES_MASK) | |
472 |
< |
((p = (int)s >>> PARTIES_SHIFT) == 0 ? EMPTY : |
473 |
< |
(u = (int)s & UNARRIVED_MASK) == 0 ? p : u)))) |
471 |
> |
((phase < 0) ? (s & COUNTS_MASK) : |
472 |
> |
(((p = (int)s >>> PARTIES_SHIFT) == 0) ? EMPTY : |
473 |
> |
((s & PARTIES_MASK) | p)))))) |
474 |
|
s = state; |
475 |
|
} |
476 |
|
return s; |
602 |
|
* of unarrived parties would become negative |
603 |
|
*/ |
604 |
|
public int arrive() { |
605 |
< |
return doArrive(false); |
605 |
> |
return doArrive(ONE_ARRIVAL); |
606 |
|
} |
607 |
|
|
608 |
|
/** |
622 |
|
* of registered or unarrived parties would become negative |
623 |
|
*/ |
624 |
|
public int arriveAndDeregister() { |
625 |
< |
return doArrive(true); |
625 |
> |
return doArrive(ONE_DEREGISTER); |
626 |
|
} |
627 |
|
|
628 |
|
/** |
649 |
|
for (;;) { |
650 |
|
long s = (root == this) ? state : reconcileState(); |
651 |
|
int phase = (int)(s >>> PHASE_SHIFT); |
640 |
– |
int counts = (int)s; |
641 |
– |
int unarrived = (counts & UNARRIVED_MASK) - 1; |
652 |
|
if (phase < 0) |
653 |
|
return phase; |
654 |
< |
else if (counts == EMPTY || unarrived < 0) { |
655 |
< |
if (reconcileState() == s) |
656 |
< |
throw new IllegalStateException(badArrive(s)); |
657 |
< |
} |
658 |
< |
else if (UNSAFE.compareAndSwapLong(this, stateOffset, s, |
659 |
< |
s -= ONE_ARRIVAL)) { |
660 |
< |
if (unarrived != 0) |
654 |
> |
int counts = (int)s; |
655 |
> |
int unarrived = (counts == EMPTY) ? 0 : (counts & UNARRIVED_MASK); |
656 |
> |
if (unarrived <= 0) |
657 |
> |
throw new IllegalStateException(badArrive(s)); |
658 |
> |
if (UNSAFE.compareAndSwapLong(this, stateOffset, s, |
659 |
> |
s -= ONE_ARRIVAL)) { |
660 |
> |
if (unarrived > 1) |
661 |
|
return root.internalAwaitAdvance(phase, null); |
662 |
|
if (root != this) |
663 |
|
return parent.arriveAndAwaitAdvance(); |
790 |
|
if (UNSAFE.compareAndSwapLong(root, stateOffset, |
791 |
|
s, s | TERMINATION_BIT)) { |
792 |
|
// signal all threads |
793 |
< |
releaseWaiters(0); |
794 |
< |
releaseWaiters(1); |
793 |
> |
releaseWaiters(0); // Waiters on evenQ |
794 |
> |
releaseWaiters(1); // Waiters on oddQ |
795 |
|
return; |
796 |
|
} |
797 |
|
} |
997 |
|
|
998 |
|
/** |
999 |
|
* Possibly blocks and waits for phase to advance unless aborted. |
1000 |
< |
* Call only from root node. |
1000 |
> |
* Call only on root phaser. |
1001 |
|
* |
1002 |
|
* @param phase current phase |
1003 |
|
* @param node if non-null, the wait node to track interrupt and timeout; |
1005 |
|
* @return current phase |
1006 |
|
*/ |
1007 |
|
private int internalAwaitAdvance(int phase, QNode node) { |
1008 |
+ |
// assert root == this; |
1009 |
|
releaseWaiters(phase-1); // ensure old queue clean |
1010 |
|
boolean queued = false; // true when node is enqueued |
1011 |
|
int lastUnarrived = 0; // to increase spins upon change |
1124 |
|
static { |
1125 |
|
try { |
1126 |
|
UNSAFE = getUnsafe(); |
1127 |
< |
Class k = Phaser.class; |
1127 |
> |
Class<?> k = Phaser.class; |
1128 |
|
stateOffset = UNSAFE.objectFieldOffset |
1129 |
|
(k.getDeclaredField("state")); |
1130 |
|
} catch (Exception e) { |