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package jsr166y; |
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import java.util.concurrent.*; |
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import java.util.Random; |
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import java.util.Collection; |
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import java.util.concurrent.locks.LockSupport; |
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import java.util.concurrent.RejectedExecutionException; |
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/** |
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* A thread managed by a {@link ForkJoinPool}. This class is |
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* subclassable solely for the sake of adding functionality -- there |
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* are no overridable methods dealing with scheduling or execution. |
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* However, you can override initialization and termination methods |
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* surrounding the main task processing loop. If you do create such a |
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* subclass, you will also need to supply a custom {@link |
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* ForkJoinPool.ForkJoinWorkerThreadFactory} to use it in a {@code |
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* ForkJoinPool}. |
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* A thread managed by a {@link ForkJoinPool}, which executes |
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* {@link ForkJoinTask}s. |
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* This class is subclassable solely for the sake of adding |
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* functionality -- there are no overridable methods dealing with |
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* scheduling or execution. However, you can override initialization |
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* and termination methods surrounding the main task processing loop. |
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* If you do create such a subclass, you will also need to supply a |
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* custom {@link ForkJoinPool.ForkJoinWorkerThreadFactory} to use it |
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* in a {@code ForkJoinPool}. |
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* |
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* @since 1.7 |
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* @author Doug Lea |
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/** |
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* Maximum work-stealing queue array size. Must be less than or |
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* equal to 1 << 28 to ensure lack of index wraparound. (This |
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* is less than usual bounds, because we need leftshift by 3 |
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* to be in int range). |
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* equal to 1 << (31 - width of array entry) to ensure lack of |
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* index wraparound. The value is set in the static block |
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* at the end of this file after obtaining width. |
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*/ |
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private static final int MAXIMUM_QUEUE_CAPACITY = 1 << 28; |
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private static final int MAXIMUM_QUEUE_CAPACITY; |
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/** |
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* The pool this thread works in. Accessed directly by ForkJoinTask. |
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private static final int TRIMMED = 0x08; // killed while suspended |
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/** |
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* Number of steals, transferred and reset in pool callbacks pool |
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* when idle Accessed directly by pool. |
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* Number of steals. Directly accessed (and reset) by |
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* pool.tryAccumulateStealCount when idle. |
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*/ |
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int stealCount; |
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|
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|
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/** |
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* The task currently being joined, set only when actively trying |
289 |
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* to helpStealer. Written only by current thread, but read by |
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* others. |
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* to help other stealers in helpJoinTask. Written only by this |
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* thread, but read by others. |
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*/ |
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private volatile ForkJoinTask<?> currentJoin; |
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|
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/** |
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* The task most recently stolen from another worker (or |
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* submission queue). Written only by current thread, but read by |
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* submission queue). Written only by this thread, but read by |
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* others. |
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*/ |
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private volatile ForkJoinTask<?> currentSteal; |
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} |
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/** |
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* Performs additional initialization and starts this thread |
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* Performs additional initialization and starts this thread. |
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*/ |
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final void start(int poolIndex, UncaughtExceptionHandler ueh) { |
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this.poolIndex = poolIndex; |
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/** |
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* Initializes internal state after construction but before |
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* processing any tasks. If you override this method, you must |
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* invoke super.onStart() at the beginning of the method. |
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* invoke {@code super.onStart()} at the beginning of the method. |
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* Initialization requires care: Most fields must have legal |
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* default values, to ensure that attempted accesses from other |
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* threads work correctly even before this thread starts |
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*/ |
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protected void onStart() { |
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int rs = seedGenerator.nextInt(); |
360 |
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seed = rs == 0? 1 : rs; // seed must be nonzero |
360 |
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seed = (rs == 0) ? 1 : rs; // seed must be nonzero |
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|
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// Allocate name string and arrays in this thread |
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String pid = Integer.toString(pool.getPoolNumber()); |
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/** |
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* This method is required to be public, but should never be |
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* called explicitly. It performs the main run loop to execute |
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* ForkJoinTasks. |
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* {@link ForkJoinTask}s. |
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*/ |
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public void run() { |
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Throwable exception = null; |
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// helpers for run() |
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/** |
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* Find and execute tasks and check status while running |
419 |
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* Finds and executes tasks, and checks status while running. |
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*/ |
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private void mainLoop() { |
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boolean ran = false; // true if ran a task on last step |
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} |
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/** |
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* Try to steal a task and execute it |
433 |
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* Tries to steal a task and execute it. |
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* |
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* @return true if ran a task |
436 |
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*/ |
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} |
448 |
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|
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/** |
450 |
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* If a submission exists, try to activate and run it; |
450 |
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* If a submission exists, try to activate and run it. |
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* |
452 |
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* @return true if ran a task |
453 |
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*/ |
454 |
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private boolean tryExecSubmission() { |
455 |
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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 |
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while (p.hasQueuedSubmissions()) { |
460 |
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ForkJoinTask<?> t; int a; |
461 |
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if (active || // inline p.tryIncrementActiveCount |
480 |
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*/ |
481 |
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private void execLocalTasks() { |
482 |
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while (runState == 0) { |
483 |
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ForkJoinTask<?> t = locallyFifo? locallyDeqTask() : popTask(); |
483 |
> |
ForkJoinTask<?> t = locallyFifo ? locallyDeqTask() : popTask(); |
484 |
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if (t != null) |
485 |
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t.quietlyExec(); |
486 |
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else if (sp == base) |
490 |
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|
491 |
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/* |
492 |
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* Intrinsics-based atomic writes for queue slots. These are |
493 |
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* basically the same as methods in AtomicObjectArray, but |
493 |
> |
* basically the same as methods in AtomicReferenceArray, but |
494 |
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* specialized for (1) ForkJoinTask elements (2) requirement that |
495 |
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* nullness and bounds checks have already been performed by |
496 |
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* callers and (3) effective offsets are known not to overflow |
497 |
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* from int to long (because of MAXIMUM_QUEUE_CAPACITY). We don't |
498 |
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* need corresponding version for reads: plain array reads are OK |
499 |
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* because they protected by other volatile reads and are |
499 |
> |
* because they are protected by other volatile reads and are |
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* confirmed by CASes. |
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* |
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* Most uses don't actually call these methods, but instead contain |
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* range. This method is used only during resets and backouts. |
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*/ |
522 |
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private static final void writeSlot(ForkJoinTask<?>[] q, int i, |
523 |
< |
ForkJoinTask<?> t) { |
523 |
> |
ForkJoinTask<?> t) { |
524 |
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UNSAFE.putObjectVolatile(q, (i << qShift) + qBase, t); |
525 |
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} |
526 |
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|
565 |
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|
566 |
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/** |
567 |
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* Tries to take a task from the base of own queue. Assumes active |
568 |
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* status. Called only by current thread. |
568 |
> |
* status. Called only by this thread. |
569 |
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* |
570 |
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* @return a task, or null if none |
571 |
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*/ |
588 |
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|
589 |
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/** |
590 |
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* Returns a popped task, or null if empty. Assumes active status. |
591 |
< |
* Called only by current thread. |
591 |
> |
* Called only by this thread. |
592 |
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*/ |
593 |
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private ForkJoinTask<?> popTask() { |
594 |
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ForkJoinTask<?>[] q = queue; |
601 |
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if (t == null) // lost to stealer |
602 |
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break; |
603 |
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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 |
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* fence. To simplify possible changes, the option |
614 |
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* is left in comments next to the associated |
615 |
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* assignments. |
616 |
+ |
*/ |
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sp = s; // putOrderedInt may encourage more timely write |
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// UNSAFE.putOrderedInt(this, spOffset, s); |
619 |
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return t; |
625 |
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|
626 |
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/** |
627 |
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* Specialized version of popTask to pop only if topmost element |
628 |
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* 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 |
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* |
630 |
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* @param t the task. Caller must ensure non-null. |
631 |
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*/ |
643 |
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} |
644 |
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|
645 |
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/** |
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 |
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ForkJoinTask<?>[] q = queue; |
685 |
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* Computes next value for random victim probe in scan(). Scans |
686 |
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* don't require a very high quality generator, but also not a |
687 |
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* 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 |
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private static final int xorShift(int r) { |
691 |
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r ^= r << 13; |
763 |
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// Run State management |
764 |
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|
765 |
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// 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) |
918 |
|
if (active || |
919 |
|
(active = UNSAFE.compareAndSwapInt(p, poolRunStateOffset, |
920 |
|
a = p.runState, a + 1))) |
921 |
< |
return locallyFifo? locallyDeqTask() : popTask(); |
921 |
> |
return locallyFifo ? locallyDeqTask() : popTask(); |
922 |
|
} |
923 |
|
return null; |
924 |
|
} |
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) { |