| 6 |
|
|
| 7 |
|
package jsr166y; |
| 8 |
|
|
| 9 |
– |
import java.util.concurrent.*; |
| 10 |
– |
|
| 9 |
|
import java.util.Random; |
| 10 |
|
import java.util.Collection; |
| 11 |
|
import java.util.concurrent.locks.LockSupport; |
| 12 |
+ |
import java.util.concurrent.RejectedExecutionException; |
| 13 |
|
|
| 14 |
|
/** |
| 15 |
< |
* A thread managed by a {@link ForkJoinPool}. This class is |
| 16 |
< |
* subclassable solely for the sake of adding functionality -- there |
| 17 |
< |
* are no overridable methods dealing with scheduling or execution. |
| 18 |
< |
* However, you can override initialization and termination methods |
| 19 |
< |
* surrounding the main task processing loop. If you do create such a |
| 20 |
< |
* subclass, you will also need to supply a custom {@link |
| 21 |
< |
* ForkJoinPool.ForkJoinWorkerThreadFactory} to use it in a {@code |
| 22 |
< |
* ForkJoinPool}. |
| 15 |
> |
* A thread managed by a {@link ForkJoinPool}, which executes |
| 16 |
> |
* {@link ForkJoinTask}s. |
| 17 |
> |
* This class is subclassable solely for the sake of adding |
| 18 |
> |
* functionality -- there are no overridable methods dealing with |
| 19 |
> |
* scheduling or execution. However, you can override initialization |
| 20 |
> |
* and termination methods surrounding the main task processing loop. |
| 21 |
> |
* If you do create such a subclass, you will also need to supply a |
| 22 |
> |
* custom {@link ForkJoinPool.ForkJoinWorkerThreadFactory} to use it |
| 23 |
> |
* in a {@code ForkJoinPool}. |
| 24 |
|
* |
| 25 |
|
* @since 1.7 |
| 26 |
|
* @author Doug Lea |
| 172 |
|
|
| 173 |
|
/** |
| 174 |
|
* Maximum work-stealing queue array size. Must be less than or |
| 175 |
< |
* equal to 1 << 28 to ensure lack of index wraparound. (This |
| 176 |
< |
* is less than usual bounds, because we need leftshift by 3 |
| 177 |
< |
* to be in int range). |
| 175 |
> |
* equal to 1 << (31 - width of array entry) to ensure lack of |
| 176 |
> |
* index wraparound. The value is set in the static block |
| 177 |
> |
* at the end of this file after obtaining width. |
| 178 |
|
*/ |
| 179 |
< |
private static final int MAXIMUM_QUEUE_CAPACITY = 1 << 28; |
| 179 |
> |
private static final int MAXIMUM_QUEUE_CAPACITY; |
| 180 |
|
|
| 181 |
|
/** |
| 182 |
|
* The pool this thread works in. Accessed directly by ForkJoinTask. |
| 230 |
|
private static final int TRIMMED = 0x08; // killed while suspended |
| 231 |
|
|
| 232 |
|
/** |
| 233 |
< |
* Number of steals, transferred and reset in pool callbacks pool |
| 234 |
< |
* when idle Accessed directly by pool. |
| 233 |
> |
* Number of steals. Directly accessed (and reset) by |
| 234 |
> |
* pool.tryAccumulateStealCount when idle. |
| 235 |
|
*/ |
| 236 |
|
int stealCount; |
| 237 |
|
|
| 286 |
|
|
| 287 |
|
/** |
| 288 |
|
* The task currently being joined, set only when actively trying |
| 289 |
< |
* to helpStealer. Written only by current thread, but read by |
| 290 |
< |
* others. |
| 289 |
> |
* to help other stealers in helpJoinTask. Written only by this |
| 290 |
> |
* thread, but read by others. |
| 291 |
|
*/ |
| 292 |
|
private volatile ForkJoinTask<?> currentJoin; |
| 293 |
|
|
| 294 |
|
/** |
| 295 |
|
* The task most recently stolen from another worker (or |
| 296 |
< |
* submission queue). Written only by current thread, but read by |
| 296 |
> |
* submission queue). Written only by this thread, but read by |
| 297 |
|
* others. |
| 298 |
|
*/ |
| 299 |
|
private volatile ForkJoinTask<?> currentSteal; |
| 313 |
|
} |
| 314 |
|
|
| 315 |
|
/** |
| 316 |
< |
* Performs additional initialization and starts this thread |
| 316 |
> |
* Performs additional initialization and starts this thread. |
| 317 |
|
*/ |
| 318 |
|
final void start(int poolIndex, UncaughtExceptionHandler ueh) { |
| 319 |
|
this.poolIndex = poolIndex; |
| 349 |
|
/** |
| 350 |
|
* Initializes internal state after construction but before |
| 351 |
|
* processing any tasks. If you override this method, you must |
| 352 |
< |
* invoke super.onStart() at the beginning of the method. |
| 352 |
> |
* invoke {@code super.onStart()} at the beginning of the method. |
| 353 |
|
* Initialization requires care: Most fields must have legal |
| 354 |
|
* default values, to ensure that attempted accesses from other |
| 355 |
|
* threads work correctly even before this thread starts |
| 399 |
|
/** |
| 400 |
|
* This method is required to be public, but should never be |
| 401 |
|
* called explicitly. It performs the main run loop to execute |
| 402 |
< |
* ForkJoinTasks. |
| 402 |
> |
* {@link ForkJoinTask}s. |
| 403 |
|
*/ |
| 404 |
|
public void run() { |
| 405 |
|
Throwable exception = null; |
| 416 |
|
// helpers for run() |
| 417 |
|
|
| 418 |
|
/** |
| 419 |
< |
* Find and execute tasks and check status while running |
| 419 |
> |
* Finds and executes tasks, and checks status while running. |
| 420 |
|
*/ |
| 421 |
|
private void mainLoop() { |
| 422 |
|
boolean ran = false; // true if ran a task on last step |
| 430 |
|
} |
| 431 |
|
|
| 432 |
|
/** |
| 433 |
< |
* Try to steal a task and execute it |
| 433 |
> |
* Tries to steal a task and execute it. |
| 434 |
|
* |
| 435 |
|
* @return true if ran a task |
| 436 |
|
*/ |
| 447 |
|
} |
| 448 |
|
|
| 449 |
|
/** |
| 450 |
< |
* If a submission exists, try to activate and run it; |
| 450 |
> |
* If a submission exists, try to activate and run it. |
| 451 |
|
* |
| 452 |
|
* @return true if ran a task |
| 453 |
|
*/ |
| 454 |
|
private boolean tryExecSubmission() { |
| 455 |
|
ForkJoinPool p = pool; |
| 456 |
+ |
// This loop is needed in case attempt to activate fails, in |
| 457 |
+ |
// which case we only retry if there still appears to be a |
| 458 |
+ |
// submission. |
| 459 |
|
while (p.hasQueuedSubmissions()) { |
| 460 |
|
ForkJoinTask<?> t; int a; |
| 461 |
|
if (active || // inline p.tryIncrementActiveCount |
| 490 |
|
|
| 491 |
|
/* |
| 492 |
|
* Intrinsics-based atomic writes for queue slots. These are |
| 493 |
< |
* basically the same as methods in AtomicObjectArray, but |
| 493 |
> |
* basically the same as methods in AtomicReferenceArray, but |
| 494 |
|
* specialized for (1) ForkJoinTask elements (2) requirement that |
| 495 |
|
* nullness and bounds checks have already been performed by |
| 496 |
|
* callers and (3) effective offsets are known not to overflow |
| 497 |
|
* from int to long (because of MAXIMUM_QUEUE_CAPACITY). We don't |
| 498 |
|
* need corresponding version for reads: plain array reads are OK |
| 499 |
< |
* because they protected by other volatile reads and are |
| 499 |
> |
* because they are protected by other volatile reads and are |
| 500 |
|
* confirmed by CASes. |
| 501 |
|
* |
| 502 |
|
* Most uses don't actually call these methods, but instead contain |
| 520 |
|
* range. This method is used only during resets and backouts. |
| 521 |
|
*/ |
| 522 |
|
private static final void writeSlot(ForkJoinTask<?>[] q, int i, |
| 523 |
< |
ForkJoinTask<?> t) { |
| 523 |
> |
ForkJoinTask<?> t) { |
| 524 |
|
UNSAFE.putObjectVolatile(q, (i << qShift) + qBase, t); |
| 525 |
|
} |
| 526 |
|
|
| 565 |
|
|
| 566 |
|
/** |
| 567 |
|
* Tries to take a task from the base of own queue. Assumes active |
| 568 |
< |
* status. Called only by current thread. |
| 568 |
> |
* status. Called only by this thread. |
| 569 |
|
* |
| 570 |
|
* @return a task, or null if none |
| 571 |
|
*/ |
| 588 |
|
|
| 589 |
|
/** |
| 590 |
|
* Returns a popped task, or null if empty. Assumes active status. |
| 591 |
< |
* Called only by current thread. |
| 591 |
> |
* Called only by this thread. |
| 592 |
|
*/ |
| 593 |
|
private ForkJoinTask<?> popTask() { |
| 594 |
|
ForkJoinTask<?>[] q = queue; |
| 601 |
|
if (t == null) // lost to stealer |
| 602 |
|
break; |
| 603 |
|
if (UNSAFE.compareAndSwapObject(q, u, t, null)) { |
| 604 |
+ |
/* |
| 605 |
+ |
* Note: here and in related methods, as a |
| 606 |
+ |
* performance (not correctness) issue, we'd like |
| 607 |
+ |
* to encourage compiler not to arbitrarily |
| 608 |
+ |
* postpone setting sp after successful CAS. |
| 609 |
+ |
* Currently there is no intrinsic for arranging |
| 610 |
+ |
* this, but using Unsafe putOrderedInt may be a |
| 611 |
+ |
* preferable strategy on some compilers even |
| 612 |
+ |
* though its main effect is a pre-, not post- |
| 613 |
+ |
* fence. To simplify possible changes, the option |
| 614 |
+ |
* is left in comments next to the associated |
| 615 |
+ |
* assignments. |
| 616 |
+ |
*/ |
| 617 |
|
sp = s; // putOrderedInt may encourage more timely write |
| 618 |
|
// UNSAFE.putOrderedInt(this, spOffset, s); |
| 619 |
|
return t; |
| 625 |
|
|
| 626 |
|
/** |
| 627 |
|
* Specialized version of popTask to pop only if topmost element |
| 628 |
< |
* is the given task. Called only by current thread while |
| 613 |
< |
* active. |
| 628 |
> |
* is the given task. Called only by this thread while active. |
| 629 |
|
* |
| 630 |
|
* @param t the task. Caller must ensure non-null. |
| 631 |
|
*/ |
| 643 |
|
} |
| 644 |
|
|
| 645 |
|
/** |
| 646 |
< |
* Returns next task or null if empty or contended |
| 646 |
> |
* Returns next task, or null if empty or contended. |
| 647 |
|
*/ |
| 648 |
|
final ForkJoinTask<?> peekTask() { |
| 649 |
|
ForkJoinTask<?>[] q = queue; |
| 685 |
|
* Computes next value for random victim probe in scan(). Scans |
| 686 |
|
* don't require a very high quality generator, but also not a |
| 687 |
|
* crummy one. Marsaglia xor-shift is cheap and works well enough. |
| 688 |
< |
* Note: This is manually inlined in scan() |
| 688 |
> |
* Note: This is manually inlined in scan(). |
| 689 |
|
*/ |
| 690 |
|
private static final int xorShift(int r) { |
| 691 |
|
r ^= r << 13; |
| 763 |
|
// Run State management |
| 764 |
|
|
| 765 |
|
// status check methods used mainly by ForkJoinPool |
| 766 |
< |
final boolean isRunning() { return runState == 0; } |
| 767 |
< |
final boolean isTerminating() { return (runState & TERMINATING) != 0; } |
| 768 |
< |
final boolean isTerminated() { return (runState & TERMINATED) != 0; } |
| 769 |
< |
final boolean isSuspended() { return (runState & SUSPENDED) != 0; } |
| 770 |
< |
final boolean isTrimmed() { return (runState & TRIMMED) != 0; } |
| 766 |
> |
final boolean isRunning() { return runState == 0; } |
| 767 |
> |
final boolean isTerminated() { return (runState & TERMINATED) != 0; } |
| 768 |
> |
final boolean isSuspended() { return (runState & SUSPENDED) != 0; } |
| 769 |
> |
final boolean isTrimmed() { return (runState & TRIMMED) != 0; } |
| 770 |
> |
|
| 771 |
> |
final boolean isTerminating() { |
| 772 |
> |
if ((runState & TERMINATING) != 0) |
| 773 |
> |
return true; |
| 774 |
> |
if (pool.isAtLeastTerminating()) { // propagate pool state |
| 775 |
> |
shutdown(); |
| 776 |
> |
return true; |
| 777 |
> |
} |
| 778 |
> |
return false; |
| 779 |
> |
} |
| 780 |
|
|
| 781 |
|
/** |
| 782 |
|
* Sets state to TERMINATING. Does NOT unpark or interrupt |
| 800 |
|
} |
| 801 |
|
|
| 802 |
|
/** |
| 803 |
< |
* Sets state to TERMINATED. Called only by onTermination() |
| 803 |
> |
* Sets state to TERMINATED. Called only by onTermination(). |
| 804 |
|
*/ |
| 805 |
|
private void setTerminated() { |
| 806 |
|
int s; |
| 870 |
|
*/ |
| 871 |
|
final void cancelTasks() { |
| 872 |
|
ForkJoinTask<?> cj = currentJoin; // try to cancel ongoing tasks |
| 873 |
< |
if (cj != null) { |
| 850 |
< |
currentJoin = null; |
| 873 |
> |
if (cj != null && cj.status >= 0) { |
| 874 |
|
cj.cancelIgnoringExceptions(); |
| 875 |
|
try { |
| 876 |
|
this.interrupt(); // awaken wait |
| 878 |
|
} |
| 879 |
|
} |
| 880 |
|
ForkJoinTask<?> cs = currentSteal; |
| 881 |
< |
if (cs != null) { |
| 859 |
< |
currentSteal = null; |
| 881 |
> |
if (cs != null && cs.status >= 0) |
| 882 |
|
cs.cancelIgnoringExceptions(); |
| 861 |
– |
} |
| 883 |
|
while (base != sp) { |
| 884 |
|
ForkJoinTask<?> t = deqTask(); |
| 885 |
|
if (t != null) |
| 942 |
|
* Possibly runs some tasks and/or blocks, until task is done. |
| 943 |
|
* |
| 944 |
|
* @param joinMe the task to join |
| 945 |
+ |
* @param timed true if use timed wait |
| 946 |
+ |
* @param nanos wait time if timed |
| 947 |
|
*/ |
| 948 |
< |
final void joinTask(ForkJoinTask<?> joinMe) { |
| 948 |
> |
final void joinTask(ForkJoinTask<?> joinMe, boolean timed, long nanos) { |
| 949 |
|
// currentJoin only written by this thread; only need ordered store |
| 950 |
|
ForkJoinTask<?> prevJoin = currentJoin; |
| 951 |
|
UNSAFE.putOrderedObject(this, currentJoinOffset, joinMe); |
| 952 |
< |
if (sp != base) |
| 930 |
< |
localHelpJoinTask(joinMe); |
| 931 |
< |
if (joinMe.status >= 0) |
| 932 |
< |
pool.awaitJoin(joinMe, this); |
| 952 |
> |
pool.awaitJoin(joinMe, this, timed, nanos); |
| 953 |
|
UNSAFE.putOrderedObject(this, currentJoinOffset, prevJoin); |
| 954 |
|
} |
| 955 |
|
|
| 956 |
|
/** |
| 957 |
< |
* Run tasks in local queue until given task is done. |
| 958 |
< |
* |
| 959 |
< |
* @param joinMe the task to join |
| 960 |
< |
*/ |
| 961 |
< |
private void localHelpJoinTask(ForkJoinTask<?> joinMe) { |
| 942 |
< |
int s; |
| 943 |
< |
ForkJoinTask<?>[] q; |
| 944 |
< |
while (joinMe.status >= 0 && (s = sp) != base && (q = queue) != null) { |
| 945 |
< |
int i = (q.length - 1) & --s; |
| 946 |
< |
long u = (i << qShift) + qBase; // raw offset |
| 947 |
< |
ForkJoinTask<?> t = q[i]; |
| 948 |
< |
if (t == null) // lost to a stealer |
| 949 |
< |
break; |
| 950 |
< |
if (UNSAFE.compareAndSwapObject(q, u, t, null)) { |
| 951 |
< |
/* |
| 952 |
< |
* This recheck (and similarly in helpJoinTask) |
| 953 |
< |
* handles cases where joinMe is independently |
| 954 |
< |
* cancelled or forced even though there is other work |
| 955 |
< |
* available. Back out of the pop by putting t back |
| 956 |
< |
* into slot before we commit by writing sp. |
| 957 |
< |
*/ |
| 958 |
< |
if (joinMe.status < 0) { |
| 959 |
< |
UNSAFE.putObjectVolatile(q, u, t); |
| 960 |
< |
break; |
| 961 |
< |
} |
| 962 |
< |
sp = s; |
| 963 |
< |
// UNSAFE.putOrderedInt(this, spOffset, s); |
| 964 |
< |
t.quietlyExec(); |
| 965 |
< |
} |
| 966 |
< |
} |
| 967 |
< |
} |
| 968 |
< |
|
| 969 |
< |
/** |
| 970 |
< |
* Unless terminating, tries to locate and help perform tasks for |
| 971 |
< |
* a stealer of the given task, or in turn one of its stealers. |
| 972 |
< |
* Traces currentSteal->currentJoin links looking for a thread |
| 973 |
< |
* working on a descendant of the given task and with a non-empty |
| 974 |
< |
* queue to steal back and execute tasks from. |
| 957 |
> |
* Tries to locate and help perform tasks for a stealer of the |
| 958 |
> |
* given task, or in turn one of its stealers. Traces |
| 959 |
> |
* currentSteal->currentJoin links looking for a thread working on |
| 960 |
> |
* a descendant of the given task and with a non-empty queue to |
| 961 |
> |
* steal back and execute tasks from. |
| 962 |
|
* |
| 963 |
|
* The implementation is very branchy to cope with potential |
| 964 |
|
* inconsistencies or loops encountering chains that are stale, |
| 968 |
|
* don't work out. |
| 969 |
|
* |
| 970 |
|
* @param joinMe the task to join |
| 971 |
< |
*/ |
| 972 |
< |
final void helpJoinTask(ForkJoinTask<?> joinMe) { |
| 973 |
< |
ForkJoinWorkerThread[] ws; |
| 974 |
< |
int n; |
| 975 |
< |
if (joinMe.status < 0) // already done |
| 976 |
< |
return; |
| 977 |
< |
if ((runState & TERMINATING) != 0) { // cancel if shutting down |
| 978 |
< |
joinMe.cancelIgnoringExceptions(); |
| 979 |
< |
return; |
| 980 |
< |
} |
| 981 |
< |
if ((ws = pool.workers) == null || (n = ws.length) <= 1) |
| 982 |
< |
return; // need at least 2 workers |
| 983 |
< |
|
| 984 |
< |
ForkJoinTask<?> task = joinMe; // base of chain |
| 985 |
< |
ForkJoinWorkerThread thread = this; // thread with stolen task |
| 986 |
< |
for (int d = 0; d < MAX_HELP_DEPTH; ++d) { // chain length |
| 987 |
< |
// Try to find v, the stealer of task, by first using hint |
| 988 |
< |
ForkJoinWorkerThread v = ws[thread.stealHint & (n - 1)]; |
| 989 |
< |
if (v == null || v.currentSteal != task) { |
| 990 |
< |
for (int j = 0; ; ++j) { // search array |
| 991 |
< |
if (j < n) { |
| 992 |
< |
ForkJoinTask<?> vs; |
| 993 |
< |
if ((v = ws[j]) != null && |
| 994 |
< |
(vs = v.currentSteal) != null) { |
| 995 |
< |
if (joinMe.status < 0 || task.status < 0) |
| 996 |
< |
return; // stale or done |
| 997 |
< |
if (vs == task) { |
| 998 |
< |
thread.stealHint = j; |
| 999 |
< |
break; // save hint for next time |
| 971 |
> |
* @param running if false, then must update pool count upon |
| 972 |
> |
* running a task |
| 973 |
> |
* @return value of running on exit |
| 974 |
> |
*/ |
| 975 |
> |
final boolean helpJoinTask(ForkJoinTask<?> joinMe, boolean running) { |
| 976 |
> |
/* |
| 977 |
> |
* Initial checks to (1) abort if terminating; (2) clean out |
| 978 |
> |
* old cancelled tasks from local queue; (3) if joinMe is next |
| 979 |
> |
* task, run it; (4) omit scan if local queue nonempty (since |
| 980 |
> |
* it may contain non-descendents of joinMe). |
| 981 |
> |
*/ |
| 982 |
> |
ForkJoinPool p = pool; |
| 983 |
> |
for (;;) { |
| 984 |
> |
ForkJoinTask<?>[] q; |
| 985 |
> |
int s; |
| 986 |
> |
if (joinMe.status < 0) |
| 987 |
> |
return running; |
| 988 |
> |
else if ((runState & TERMINATING) != 0) { |
| 989 |
> |
joinMe.cancelIgnoringExceptions(); |
| 990 |
> |
return running; |
| 991 |
> |
} |
| 992 |
> |
else if ((s = sp) == base || (q = queue) == null) |
| 993 |
> |
break; // queue empty |
| 994 |
> |
else { |
| 995 |
> |
int i = (q.length - 1) & --s; |
| 996 |
> |
long u = (i << qShift) + qBase; // raw offset |
| 997 |
> |
ForkJoinTask<?> t = q[i]; |
| 998 |
> |
if (t == null) |
| 999 |
> |
break; // lost to a stealer |
| 1000 |
> |
else if (t != joinMe && t.status >= 0) |
| 1001 |
> |
return running; // cannot safely help |
| 1002 |
> |
else if ((running || |
| 1003 |
> |
(running = p.tryIncrementRunningCount())) && |
| 1004 |
> |
UNSAFE.compareAndSwapObject(q, u, t, null)) { |
| 1005 |
> |
sp = s; // putOrderedInt may encourage more timely write |
| 1006 |
> |
// UNSAFE.putOrderedInt(this, spOffset, s); |
| 1007 |
> |
t.quietlyExec(); |
| 1008 |
> |
} |
| 1009 |
> |
} |
| 1010 |
> |
} |
| 1011 |
> |
|
| 1012 |
> |
int n; // worker array size |
| 1013 |
> |
ForkJoinWorkerThread[] ws = p.workers; |
| 1014 |
> |
if (ws != null && (n = ws.length) > 1) { // need at least 2 workers |
| 1015 |
> |
ForkJoinTask<?> task = joinMe; // base of chain |
| 1016 |
> |
ForkJoinWorkerThread thread = this; // thread with stolen task |
| 1017 |
> |
|
| 1018 |
> |
outer:for (int d = 0; d < MAX_HELP_DEPTH; ++d) { // chain length |
| 1019 |
> |
// Try to find v, the stealer of task, by first using hint |
| 1020 |
> |
ForkJoinWorkerThread v = ws[thread.stealHint & (n - 1)]; |
| 1021 |
> |
if (v == null || v.currentSteal != task) { |
| 1022 |
> |
for (int j = 0; ; ++j) { // search array |
| 1023 |
> |
if (j < n) { |
| 1024 |
> |
ForkJoinTask<?> vs; |
| 1025 |
> |
if ((v = ws[j]) != null && |
| 1026 |
> |
(vs = v.currentSteal) != null) { |
| 1027 |
> |
if (joinMe.status < 0) |
| 1028 |
> |
break outer; |
| 1029 |
> |
if (vs == task) { |
| 1030 |
> |
if (task.status < 0) |
| 1031 |
> |
break outer; // stale |
| 1032 |
> |
thread.stealHint = j; |
| 1033 |
> |
break; // save hint for next time |
| 1034 |
> |
} |
| 1035 |
|
} |
| 1036 |
|
} |
| 1037 |
+ |
else |
| 1038 |
+ |
break outer; // no stealer |
| 1039 |
|
} |
| 1016 |
– |
else |
| 1017 |
– |
return; // no stealer |
| 1040 |
|
} |
| 1041 |
< |
} |
| 1042 |
< |
for (;;) { // Try to help v, using specialized form of deqTask |
| 1043 |
< |
if (joinMe.status < 0) |
| 1044 |
< |
return; |
| 1045 |
< |
int b = v.base; |
| 1046 |
< |
ForkJoinTask<?>[] q = v.queue; |
| 1047 |
< |
if (b == v.sp || q == null) |
| 1048 |
< |
break; |
| 1049 |
< |
int i = (q.length - 1) & b; |
| 1050 |
< |
long u = (i << qShift) + qBase; |
| 1051 |
< |
ForkJoinTask<?> t = q[i]; |
| 1052 |
< |
int pid = poolIndex; |
| 1053 |
< |
ForkJoinTask<?> ps = currentSteal; |
| 1054 |
< |
if (task.status < 0) |
| 1055 |
< |
return; // stale or done |
| 1056 |
< |
if (t != null && v.base == b++ && |
| 1057 |
< |
UNSAFE.compareAndSwapObject(q, u, t, null)) { |
| 1058 |
< |
if (joinMe.status < 0) { |
| 1059 |
< |
UNSAFE.putObjectVolatile(q, u, t); |
| 1060 |
< |
return; // back out on cancel |
| 1041 |
> |
|
| 1042 |
> |
// Try to help v, using specialized form of deqTask |
| 1043 |
> |
for (;;) { |
| 1044 |
> |
if (joinMe.status < 0) |
| 1045 |
> |
break outer; |
| 1046 |
> |
int b = v.base; |
| 1047 |
> |
ForkJoinTask<?>[] q = v.queue; |
| 1048 |
> |
if (b == v.sp || q == null) |
| 1049 |
> |
break; // empty |
| 1050 |
> |
int i = (q.length - 1) & b; |
| 1051 |
> |
long u = (i << qShift) + qBase; |
| 1052 |
> |
ForkJoinTask<?> t = q[i]; |
| 1053 |
> |
if (task.status < 0) |
| 1054 |
> |
break outer; // stale |
| 1055 |
> |
if (t != null && |
| 1056 |
> |
(running || |
| 1057 |
> |
(running = p.tryIncrementRunningCount())) && |
| 1058 |
> |
v.base == b++ && |
| 1059 |
> |
UNSAFE.compareAndSwapObject(q, u, t, null)) { |
| 1060 |
> |
if (t != joinMe && joinMe.status < 0) { |
| 1061 |
> |
UNSAFE.putObjectVolatile(q, u, t); |
| 1062 |
> |
break outer; // joinMe cancelled; back out |
| 1063 |
> |
} |
| 1064 |
> |
v.base = b; |
| 1065 |
> |
if (t.status >= 0) { |
| 1066 |
> |
ForkJoinTask<?> ps = currentSteal; |
| 1067 |
> |
int pid = poolIndex; |
| 1068 |
> |
v.stealHint = pid; |
| 1069 |
> |
UNSAFE.putOrderedObject(this, |
| 1070 |
> |
currentStealOffset, t); |
| 1071 |
> |
t.quietlyExec(); |
| 1072 |
> |
UNSAFE.putOrderedObject(this, |
| 1073 |
> |
currentStealOffset, ps); |
| 1074 |
> |
} |
| 1075 |
> |
} |
| 1076 |
> |
else if ((runState & TERMINATING) != 0) { |
| 1077 |
> |
joinMe.cancelIgnoringExceptions(); |
| 1078 |
> |
break outer; |
| 1079 |
|
} |
| 1040 |
– |
v.base = b; |
| 1041 |
– |
v.stealHint = pid; |
| 1042 |
– |
UNSAFE.putOrderedObject(this, currentStealOffset, t); |
| 1043 |
– |
t.quietlyExec(); |
| 1044 |
– |
UNSAFE.putOrderedObject(this, currentStealOffset, ps); |
| 1080 |
|
} |
| 1081 |
+ |
|
| 1082 |
+ |
// Try to descend to find v's stealer |
| 1083 |
+ |
ForkJoinTask<?> next = v.currentJoin; |
| 1084 |
+ |
if (task.status < 0 || next == null || next == task || |
| 1085 |
+ |
joinMe.status < 0) |
| 1086 |
+ |
break; // done, stale, dead-end, or cyclic |
| 1087 |
+ |
task = next; |
| 1088 |
+ |
thread = v; |
| 1089 |
|
} |
| 1047 |
– |
// Try to descend to find v's stealer |
| 1048 |
– |
ForkJoinTask<?> next = v.currentJoin; |
| 1049 |
– |
if (task.status < 0 || next == null || next == task || |
| 1050 |
– |
joinMe.status < 0) |
| 1051 |
– |
return; |
| 1052 |
– |
task = next; |
| 1053 |
– |
thread = v; |
| 1090 |
|
} |
| 1091 |
+ |
return running; |
| 1092 |
|
} |
| 1093 |
|
|
| 1094 |
|
/** |
| 1095 |
+ |
* Implements ForkJoinTask.getSurplusQueuedTaskCount(). |
| 1096 |
|
* Returns an estimate of the number of tasks, offset by a |
| 1097 |
|
* function of number of idle workers. |
| 1098 |
|
* |
| 1195 |
|
if ((s & (s-1)) != 0) |
| 1196 |
|
throw new Error("data type scale not a power of two"); |
| 1197 |
|
qShift = 31 - Integer.numberOfLeadingZeros(s); |
| 1198 |
+ |
MAXIMUM_QUEUE_CAPACITY = 1 << (31 - qShift); |
| 1199 |
|
} |
| 1200 |
|
|
| 1201 |
|
private static long objectFieldOffset(String field, Class<?> klazz) { |
