[ViewVC] Diff of: jsr166/jsr166/src/jsr166y/ForkJoinPool.java

Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.132 by jsr166, Fri Oct 12 16:46:37 2012 UTC vs.
Revision 1.145 by jsr166, Mon Nov 19 01:04:24 2012 UTC

#	Line 5 \| Line 5
5		*/
6
7		package jsr166y;
8	+
9		import java.util.ArrayList;
10		import java.util.Arrays;
11		import java.util.Collection;
12		import java.util.Collections;
13		import java.util.List;
13	–	import java.util.Random;
14		import java.util.concurrent.AbstractExecutorService;
15		import java.util.concurrent.Callable;
16		import java.util.concurrent.ExecutorService;
#	Line 18 \| Line 18 \| import java.util.concurrent.Future;
18		import java.util.concurrent.RejectedExecutionException;
19		import java.util.concurrent.RunnableFuture;
20		import java.util.concurrent.TimeUnit;
21	–	import java.util.concurrent.atomic.AtomicInteger;
22	–	import java.util.concurrent.atomic.AtomicLong;
23	–	import java.util.concurrent.locks.AbstractQueuedSynchronizer;
24	–	import java.util.concurrent.locks.Condition;
21
22		/**
23		* An {@link ExecutorService} for running {@link ForkJoinTask}s.
#	Line 41 \| Line 37 \| import java.util.concurrent.locks.Condit
37		* ForkJoinPool}s may also be appropriate for use with event-style
38		* tasks that are never joined.
39		*
40	<	* <p>A {@code ForkJoinPool} is constructed with a given target
41	<	* parallelism level; by default, equal to the number of available
42	<	* processors. The pool attempts to maintain enough active (or
43	<	* available) threads by dynamically adding, suspending, or resuming
44	<	* internal worker threads, even if some tasks are stalled waiting to
45	<	* join others. However, no such adjustments are guaranteed in the
46	<	* face of blocked IO or other unmanaged synchronization. The nested
47	<	* {@link ManagedBlocker} interface enables extension of the kinds of
40	>	* <p>A static {@link #commonPool} is available and appropriate for
41	>	* most applications. The common pool is used by any ForkJoinTask that
42	>	* is not explicitly submitted to a specified pool. Using the common
43	>	* pool normally reduces resource usage (its threads are slowly
44	>	* reclaimed during periods of non-use, and reinstated upon subsequent
45	>	* use).
46	>	*
47	>	* <p>For applications that require separate or custom pools, a {@code
48	>	* ForkJoinPool} may be constructed with a given target parallelism
49	>	* level; by default, equal to the number of available processors. The
50	>	* pool attempts to maintain enough active (or available) threads by
51	>	* dynamically adding, suspending, or resuming internal worker
52	>	* threads, even if some tasks are stalled waiting to join
53	>	* others. However, no such adjustments are guaranteed in the face of
54	>	* blocked IO or other unmanaged synchronization. The nested {@link
55	>	* ManagedBlocker} interface enables extension of the kinds of
56		* synchronization accommodated.
57		*
58		* <p>In addition to execution and lifecycle control methods, this
#	Line 58 \| Line 62 \| import java.util.concurrent.locks.Condit
62		* {@link #toString} returns indications of pool state in a
63		* convenient form for informal monitoring.
64		*
65	<	* <p> As is the case with other ExecutorServices, there are three
65	>	* <p>As is the case with other ExecutorServices, there are three
66		* main task execution methods summarized in the following table.
67		* These are designed to be used primarily by clients not already
68		* engaged in fork/join computations in the current pool. The main
#	Line 93 \| Line 97 \| import java.util.concurrent.locks.Condit
97		* </tr>
98		* </table>
99		*
100	<	* <p><b>Sample Usage.</b> Normally a single {@code ForkJoinPool} is
101	<	* used for all parallel task execution in a program or subsystem.
102	<	* Otherwise, use would not usually outweigh the construction and
103	<	* bookkeeping overhead of creating a large set of threads. For
104	<	* example, a common pool could be used for the {@code SortTasks}
105	<	* illustrated in {@link RecursiveAction}. Because {@code
106	<	* ForkJoinPool} uses threads in {@linkplain java.lang.Thread#isDaemon
107	<	* daemon} mode, there is typically no need to explicitly {@link
108	<	* #shutdown} such a pool upon program exit.
109	<	*
106	<	* <pre> {@code
107	<	* static final ForkJoinPool mainPool = new ForkJoinPool();
108	<	* ...
109	<	* public void sort(long[] array) {
110	<	* mainPool.invoke(new SortTask(array, 0, array.length));
111	<	* }}</pre>
100	>	* <p>The common pool is by default constructed with default
101	>	* parameters, but these may be controlled by setting three {@link
102	>	* System#getProperty properties} with prefix {@code
103	>	* java.util.concurrent.ForkJoinPool.common}: {@code parallelism} --
104	>	* an integer greater than zero, {@code threadFactory} -- the class
105	>	* name of a {@link ForkJoinWorkerThreadFactory}, and {@code
106	>	* exceptionHandler} -- the class name of a {@link
107	>	* java.lang.Thread.UncaughtExceptionHandler
108	>	* Thread.UncaughtExceptionHandler}. Upon any error in establishing
109	>	* these settings, default parameters are used.
110		*
111		* <p><b>Implementation notes</b>: This implementation restricts the
112		* maximum number of running threads to 32767. Attempts to create
#	Line 196 \| Line 194 \| public class ForkJoinPool extends Abstra
194		* WorkQueues are also used in a similar way for tasks submitted
195		* to the pool. We cannot mix these tasks in the same queues used
196		* for work-stealing (this would contaminate lifo/fifo
197	<	* processing). Instead, we loosely associate submission queues
197	>	* processing). Instead, we randomly associate submission queues
198		* with submitting threads, using a form of hashing. The
199		* ThreadLocal Submitter class contains a value initially used as
200		* a hash code for choosing existing queues, but may be randomly
201		* repositioned upon contention with other submitters. In
202	<	* essence, submitters act like workers except that they never
203	<	* take tasks, and they are multiplexed on to a finite number of
204	<	* shared work queues. However, classes are set up so that future
205	<	* extensions could allow submitters to optionally help perform
206	<	* tasks as well. Insertion of tasks in shared mode requires a
207	<	* lock (mainly to protect in the case of resizing) but we use
208	<	* only a simple spinlock (using bits in field runState), because
209	<	* submitters encountering a busy queue move on to try or create
210	<	* other queues -- they block only when creating and registering
211	<	* new queues.
202	>	* essence, submitters act like workers except that they are
203	>	* restricted to executing local tasks that they submitted (or in
204	>	* the case of CountedCompleters, others with the same root task).
205	>	* However, because most shared/external queue operations are more
206	>	* expensive than internal, and because, at steady state, external
207	>	* submitters will compete for CPU with workers, ForkJoinTask.join
208	>	* and related methods disable them from repeatedly helping to
209	>	* process tasks if all workers are active. Insertion of tasks in
210	>	* shared mode requires a lock (mainly to protect in the case of
211	>	* resizing) but we use only a simple spinlock (using bits in
212	>	* field qlock), because submitters encountering a busy queue move
213	>	* on to try or create other queues -- they block only when
214	>	* creating and registering new queues.
215		*
216		* Management
217		* ==========
#	Line 232 \| Line 233 \| public class ForkJoinPool extends Abstra
233		* and their negations (used for thresholding) to fit into 16bit
234		* fields.
235		*
236	<	* Field "runState" contains 32 bits needed to register and
237	<	* deregister WorkQueues, as well as to enable shutdown. It is
238	<	* only modified under a lock (normally briefly held, but
239	<	* occasionally protecting allocations and resizings) but even
240	<	* when locked remains available to check consistency.
236	>	* Field "plock" is a form of sequence lock with a saturating
237	>	* shutdown bit (similarly for per-queue "qlocks"), mainly
238	>	* protecting updates to the workQueues array, as well as to
239	>	* enable shutdown. When used as a lock, it is normally only very
240	>	* briefly held, so is nearly always available after at most a
241	>	* brief spin, but we use a monitor-based backup strategy to
242	>	* blocking when needed.
243		*
244		* Recording WorkQueues. WorkQueues are recorded in the
245	<	* "workQueues" array that is created upon pool construction and
246	<	* expanded if necessary. Updates to the array while recording
247	<	* new workers and unrecording terminated ones are protected from
248	<	* each other by a lock but the array is otherwise concurrently
249	<	* readable, and accessed directly. To simplify index-based
250	<	* operations, the array size is always a power of two, and all
251	<	* readers must tolerate null slots. Shared (submission) queues
252	<	* are at even indices, worker queues at odd indices. Grouping
253	<	* them together in this way simplifies and speeds up task
254	<	* scanning.
245	>	* "workQueues" array that is created upon first use and expanded
246	>	* if necessary. Updates to the array while recording new workers
247	>	* and unrecording terminated ones are protected from each other
248	>	* by a lock but the array is otherwise concurrently readable, and
249	>	* accessed directly. To simplify index-based operations, the
250	>	* array size is always a power of two, and all readers must
251	>	* tolerate null slots. Worker queues are at odd indices Shared
252	>	* (submission) queues are at even indices, up to a maximum of 64
253	>	* slots, to limit growth even if array needs to expand to add
254	>	* more workers. Grouping them together in this way simplifies and
255	>	* speeds up task scanning.
256		*
257		* All worker thread creation is on-demand, triggered by task
258		* submissions, replacement of terminated workers, and/or
#	Line 309 \| Line 313 \| public class ForkJoinPool extends Abstra
313		*
314		* Signalling. We create or wake up workers only when there
315		* appears to be at least one task they might be able to find and
316	<	* execute. When a submission is added or another worker adds a
317	<	* task to a queue that previously had fewer than two tasks, they
318	<	* signal waiting workers (or trigger creation of new ones if
319	<	* fewer than the given parallelism level -- see signalWork).
320	<	* These primary signals are buttressed by signals during rescans;
321	<	* together these cover the signals needed in cases when more
322	<	* tasks are pushed but untaken, and improve performance compared
323	<	* to having one thread wake up all workers.
316	>	* execute. However, many other threads may notice the same task
317	>	* and each signal to wake up a thread that might take it. So in
318	>	* general, pools will be over-signalled. When a submission is
319	>	* added or another worker adds a task to a queue that is
320	>	* apparently empty, they signal waiting workers (or trigger
321	>	* creation of new ones if fewer than the given parallelism level
322	>	* -- see signalWork). These primary signals are buttressed by
323	>	* signals whenever other threads scan for work or do not have a
324	>	* task to process. On most platforms, signalling (unpark)
325	>	* overhead time is noticeably long, and the time between
326	>	* signalling a thread and it actually making progress can be very
327	>	* noticeably long, so it is worth offloading these delays from
328	>	* critical paths as much as possible.
329		*
330		* Trimming workers. To release resources after periods of lack of
331		* use, a worker starting to wait when the pool is quiescent will
332	<	* time out and terminate if the pool has remained quiescent for
333	<	* SHRINK_RATE nanosecs. This will slowly propagate, eventually
334	<	* terminating all workers after long periods of non-use.
332	>	* time out and terminate if the pool has remained quiescent for a
333	>	* given period -- a short period if there are more threads than
334	>	* parallelism, longer as the number of threads decreases. This
335	>	* will slowly propagate, eventually terminating all workers after
336	>	* periods of non-use.
337		*
338		* Shutdown and Termination. A call to shutdownNow atomically sets
339	<	* a runState bit and then (non-atomically) sets each worker's
340	<	* runState status, cancels all unprocessed tasks, and wakes up
339	>	* a plock bit and then (non-atomically) sets each worker's
340	>	* qlock status, cancels all unprocessed tasks, and wakes up
341		* all waiting workers. Detecting whether termination should
342		* commence after a non-abrupt shutdown() call requires more work
343		* and bookkeeping. We need consensus about quiescence (i.e., that
#	Line 354 \| Line 365 \| public class ForkJoinPool extends Abstra
365		* method tryCompensate() may create or re-activate a spare
366		* thread to compensate for blocked joiners until they unblock.
367		*
368	<	* A third form (implemented in tryRemoveAndExec and
369	<	* tryPollForAndExec) amounts to helping a hypothetical
370	<	* compensator: If we can readily tell that a possible action of a
371	<	* compensator is to steal and execute the task being joined, the
372	<	* joining thread can do so directly, without the need for a
373	<	* compensation thread (although at the expense of larger run-time
374	<	* stacks, but the tradeoff is typically worthwhile).
368	>	* A third form (implemented in tryRemoveAndExec) amounts to
369	>	* helping a hypothetical compensator: If we can readily tell that
370	>	* a possible action of a compensator is to steal and execute the
371	>	* task being joined, the joining thread can do so directly,
372	>	* without the need for a compensation thread (although at the
373	>	* expense of larger run-time stacks, but the tradeoff is
374	>	* typically worthwhile).
375		*
376		* The ManagedBlocker extension API can't use helping so relies
377		* only on compensation in method awaitBlocker.
#	Line 395 \| Line 406 \| public class ForkJoinPool extends Abstra
406		* to find work (see MAX_HELP) and fall back to suspending the
407		* worker and if necessary replacing it with another.
408		*
409	+	* Helping actions for CountedCompleters are much simpler: Method
410	+	* helpComplete can take and execute any task with the same root
411	+	* as the task being waited on. However, this still entails some
412	+	* traversal of completer chains, so is less efficient than using
413	+	* CountedCompleters without explicit joins.
414	+	*
415		* It is impossible to keep exactly the target parallelism number
416		* of threads running at any given time. Determining the
417		* existence of conservatively safe helping targets, the
#	Line 416 \| Line 433 \| public class ForkJoinPool extends Abstra
433		* intractable) game with an opponent that may choose the worst
434		* (for us) active thread to stall at any time. We take several
435		* precautions to bound losses (and thus bound gains), mainly in
436	<	* methods tryCompensate and awaitJoin: (1) We only try
437	<	* compensation after attempting enough helping steps (measured
438	<	* via counting and timing) that we have already consumed the
439	<	* estimated cost of creating and activating a new thread. (2) We
440	<	* allow up to 50% of threads to be blocked before initially
441	<	* adding any others, and unless completely saturated, check that
442	<	* some work is available for a new worker before adding. Also, we
443	<	* create up to only 50% more threads until entering a mode that
444	<	* only adds a thread if all others are possibly blocked. All
445	<	* together, this means that we might be half as fast to react,
446	<	* and create half as many threads as possible in the ideal case,
447	<	* but present vastly fewer anomalies in all other cases compared
448	<	* to both more aggressive and more conservative alternatives.
449	<	*
450	<	* Style notes: There is a lot of representation-level coupling
451	<	* among classes ForkJoinPool, ForkJoinWorkerThread, and
452	<	* ForkJoinTask. The fields of WorkQueue maintain data structures
453	<	* managed by ForkJoinPool, so are directly accessed. There is
454	<	* little point trying to reduce this, since any associated future
455	<	* changes in representations will need to be accompanied by
456	<	* algorithmic changes anyway. Several methods intrinsically
457	<	* sprawl because they must accumulate sets of consistent reads of
458	<	* volatiles held in local variables. Methods signalWork() and
459	<	* scan() are the main bottlenecks, so are especially heavily
436	>	* methods tryCompensate and awaitJoin.
437	>	*
438	>	* Common Pool
439	>	* ===========
440	>	*
441	>	* The static commonPool always exists after static
442	>	* initialization. Since it (or any other created pool) need
443	>	* never be used, we minimize initial construction overhead and
444	>	* footprint to the setup of about a dozen fields, with no nested
445	>	* allocation. Most bootstrapping occurs within method
446	>	* fullExternalPush during the first submission to the pool.
447	>	*
448	>	* When external threads submit to the common pool, they can
449	>	* perform some subtask processing (see externalHelpJoin and
450	>	* related methods). We do not need to record whether these
451	>	* submissions are to the common pool -- if not, externalHelpJoin
452	>	* returns quickly (at the most helping to signal some common pool
453	>	* workers). These submitters would otherwise be blocked waiting
454	>	* for completion, so the extra effort (with liberally sprinkled
455	>	* task status checks) in inapplicable cases amounts to an odd
456	>	* form of limited spin-wait before blocking in ForkJoinTask.join.
457	>	*
458	>	* Style notes
459	>	* ===========
460	>	*
461	>	* There is a lot of representation-level coupling among classes
462	>	* ForkJoinPool, ForkJoinWorkerThread, and ForkJoinTask. The
463	>	* fields of WorkQueue maintain data structures managed by
464	>	* ForkJoinPool, so are directly accessed. There is little point
465	>	* trying to reduce this, since any associated future changes in
466	>	* representations will need to be accompanied by algorithmic
467	>	* changes anyway. Several methods intrinsically sprawl because
468	>	* they must accumulate sets of consistent reads of volatiles held
469	>	* in local variables. Methods signalWork() and scan() are the
470	>	* main bottlenecks, so are especially heavily
471		* micro-optimized/mangled. There are lots of inline assignments
472		* (of form "while ((local = field) != 0)") which are usually the
473		* simplest way to ensure the required read orderings (which are
#	Line 447 \| Line 475 \| public class ForkJoinPool extends Abstra
475		* declarations of these locals at the heads of methods or blocks.
476		* There are several occurrences of the unusual "do {} while
477		* (!cas...)" which is the simplest way to force an update of a
478	<	* CAS'ed variable. There are also other coding oddities that help
478	>	* CAS'ed variable. There are also other coding oddities (including
479	>	* several unnecessary-looking hoisted null checks) that help
480		* some methods perform reasonably even when interpreted (not
481		* compiled).
482		*
#	Line 504 \| Line 533 \| public class ForkJoinPool extends Abstra
533		}
534
535		/**
507	–	* A simple non-reentrant lock used for exclusion when managing
508	–	* queues and workers. We use a custom lock so that we can readily
509	–	* probe lock state in constructions that check among alternative
510	–	* actions. The lock is normally only very briefly held, and
511	–	* sometimes treated as a spinlock, but other usages block to
512	–	* reduce overall contention in those cases where locked code
513	–	* bodies perform allocation/resizing.
514	–	*/
515	–	static final class Mutex extends AbstractQueuedSynchronizer {
516	–	public final boolean tryAcquire(int ignore) {
517	–	return compareAndSetState(0, 1);
518	–	}
519	–	public final boolean tryRelease(int ignore) {
520	–	setState(0);
521	–	return true;
522	–	}
523	–	public final void lock() { acquire(0); }
524	–	public final void unlock() { release(0); }
525	–	public final boolean isHeldExclusively() { return getState() == 1; }
526	–	public final Condition newCondition() { return new ConditionObject(); }
527	–	}
528	–
529	–	/**
536		* Class for artificial tasks that are used to replace the target
537		* of local joins if they are removed from an interior queue slot
538		* in WorkQueue.tryRemoveAndExec. We don't need the proxy to
539		* actually do anything beyond having a unique identity.
540		*/
541		static final class EmptyTask extends ForkJoinTask<Void> {
542	+	private static final long serialVersionUID = -7721805057305804111L;
543		EmptyTask() { status = ForkJoinTask.NORMAL; } // force done
544		public final Void getRawResult() { return null; }
545		public final void setRawResult(Void x) {}
#	Line 553 \| Line 560 \| public class ForkJoinPool extends Abstra
560		*
561		* Field "top" is the index (mod array.length) of the next queue
562		* slot to push to or pop from. It is written only by owner thread
563	<	* for push, or under lock for trySharedPush, and accessed by
564	<	* other threads only after reading (volatile) base. Both top and
565	<	* base are allowed to wrap around on overflow, but (top - base)
566	<	* (or more commonly -(base - top) to force volatile read of base
567	<	* before top) still estimates size.
563	>	* for push, or under lock for external/shared push, and accessed
564	>	* by other threads only after reading (volatile) base. Both top
565	>	* and base are allowed to wrap around on overflow, but (top -
566	>	* base) (or more commonly -(base - top) to force volatile read of
567	>	* base before top) still estimates size. The lock ("qlock") is
568	>	* forced to -1 on termination, causing all further lock attempts
569	>	* to fail. (Note: we don't need CAS for termination state because
570	>	* upon pool shutdown, all shared-queues will stop being used
571	>	* anyway.) Nearly all lock bodies are set up so that exceptions
572	>	* within lock bodies are "impossible" (modulo JVM errors that
573	>	* would cause failure anyway.)
574		*
575		* The array slots are read and written using the emulation of
576		* volatiles/atomics provided by Unsafe. Insertions must in
577		* general use putOrderedObject as a form of releasing store to
578		* ensure that all writes to the task object are ordered before
579	<	* its publication in the queue. (Although we can avoid one case
580	<	* of this when locked in trySharedPush.) All removals entail a
581	<	* CAS to null. The array is always a power of two. To ensure
582	<	* safety of Unsafe array operations, all accesses perform
570	<	* explicit null checks and implicit bounds checks via
571	<	* power-of-two masking.
579	>	* its publication in the queue. All removals entail a CAS to
580	>	* null. The array is always a power of two. To ensure safety of
581	>	* Unsafe array operations, all accesses perform explicit null
582	>	* checks and implicit bounds checks via power-of-two masking.
583		*
584		* In addition to basic queuing support, this class contains
585		* fields described elsewhere to control execution. It turns out
586	<	* to work better memory-layout-wise to include them in this
587	<	* class rather than a separate class.
586	>	* to work better memory-layout-wise to include them in this class
587	>	* rather than a separate class.
588		*
589		* Performance on most platforms is very sensitive to placement of
590		* instances of both WorkQueues and their arrays -- we absolutely
#	Line 589 \| Line 600 \| public class ForkJoinPool extends Abstra
600		* support is in place, this padding is dependent on transient
601		* properties of JVM field layout rules.) We also take care in
602		* allocating, sizing and resizing the array. Non-shared queue
603	<	* arrays are initialized (via method growArray) by workers before
604	<	* use. Others are allocated on first use.
603	>	* arrays are initialized by workers before use. Others are
604	>	* allocated on first use.
605		*/
606		static final class WorkQueue {
607		/**
#	Line 613 \| Line 624 \| public class ForkJoinPool extends Abstra
624		*/
625		static final int MAXIMUM_QUEUE_CAPACITY = 1 << 26; // 64M
626
616	–	volatile long totalSteals; // cumulative number of steals
627		int seed; // for random scanning; initialize nonzero
628		volatile int eventCount; // encoded inactivation count; < 0 if inactive
629		int nextWait; // encoded record of next event waiter
620	–	int rescans; // remaining scans until block
621	–	int nsteals; // top-level task executions since last idle
630		final int mode; // lifo, fifo, or shared
631	+	int nsteals; // cumulative number of steals
632		int poolIndex; // index of this queue in pool (or 0)
633		int stealHint; // index of most recent known stealer
634	<	volatile int runState; // 1: locked, -1: terminate; else 0
634	>	volatile int qlock; // 1: locked, -1: terminate; else 0
635		volatile int base; // index of next slot for poll
636		int top; // index of next slot for push
637		ForkJoinTask<?>[] array; // the elements (initially unallocated)
#	Line 644 \| Line 653 \| public class ForkJoinPool extends Abstra
653		}
654
655		/**
647	–	* Returns the approximate number of tasks in the queue.
648	–	*/
649	–	final int queueSize() {
650	–	int n = base - top; // non-owner callers must read base first
651	–	return (n >= 0) ? 0 : -n; // ignore transient negative
652	–	}
653	–
654	–	/**
655	–	* Provides a more accurate estimate of whether this queue has
656	–	* any tasks than does queueSize, by checking whether a
657	–	* near-empty queue has at least one unclaimed task.
658	–	*/
659	–	final boolean isEmpty() {
660	–	ForkJoinTask<?>[] a; int m, s;
661	–	int n = base - (s = top);
662	–	return (n >= 0 \|\|
663	–	(n == -1 &&
664	–	((a = array) == null \|\|
665	–	(m = a.length - 1) < 0 \|\|
666	–	U.getObjectVolatile
667	–	(a, ((m & (s - 1)) << ASHIFT) + ABASE) == null)));
668	–	}
669	–
670	–	/**
656		* Pushes a task. Call only by owner in unshared queues.
657	+	* Cases needing resizing or rejection are relayed to fullPush
658	+	* (that also handles shared queues).
659		*
660		* @param task the task. Caller must ensure non-null.
661		* @throw RejectedExecutionException if array cannot be resized
662		*/
663		final void push(ForkJoinTask<?> task) {
664	<	ForkJoinTask<?>[] a; ForkJoinPool p;
665	<	int s = top, m, n;
666	<	if ((a = array) != null) { // ignore if queue removed
664	>	ForkJoinPool p; ForkJoinTask<?>[] a;
665	>	int s = top, n;
666	>	if ((a = array) != null && a.length > (n = s + 1 - base)) {
667		U.putOrderedObject
668	<	(a, (((m = a.length - 1) & s) << ASHIFT) + ABASE, task);
669	<	if ((n = (top = s + 1) - base) <= 2) {
670	<	if ((p = pool) != null)
671	<	p.signalWork();
685	<	}
686	<	else if (n >= m)
687	<	growArray(true);
668	>	(a, (((a.length - 1) & s) << ASHIFT) + ABASE, task);
669	>	top = s + 1;
670	>	if (n <= 1 && (p = pool) != null)
671	>	p.signalWork(this, 1);
672		}
673	+	else
674	+	fullPush(task, true);
675		}
676
677		/**
678		* Pushes a task if lock is free and array is either big
679	<	* enough or can be resized to be big enough.
679	>	* enough or can be resized to be big enough. Note: a
680	>	* specialization of a common fast path of this method is in
681	>	* ForkJoinPool.externalPush. When called from a FJWT queue,
682	>	* this can fail only if the pool has been shut down or
683	>	* an out of memory error.
684		*
685		* @param task the task. Caller must ensure non-null.
686	<	* @return true if submitted
686	>	* @param owned if true, throw RJE on failure
687		*/
688	<	final boolean trySharedPush(ForkJoinTask<?> task) {
689	<	boolean submitted = false;
690	<	if (runState == 0 && U.compareAndSwapInt(this, RUNSTATE, 0, 1)) {
691	<	ForkJoinTask<?>[] a = array;
692	<	int s = top;
693	<	try {
694	<	if ((a != null && a.length > s + 1 - base) \|\|
695	<	(a = growArray(false)) != null) { // must presize
696	<	int j = (((a.length - 1) & s) << ASHIFT) + ABASE;
697	<	U.putObject(a, (long)j, task); // don't need "ordered"
698	<	top = s + 1;
699	<	submitted = true;
688	>	final boolean fullPush(ForkJoinTask<?> task, boolean owned) {
689	>	ForkJoinPool p; ForkJoinTask<?>[] a;
690	>	if (owned) {
691	>	if (qlock < 0) // must be shutting down
692	>	throw new RejectedExecutionException();
693	>	}
694	>	else if (!U.compareAndSwapInt(this, QLOCK, 0, 1))
695	>	return false;
696	>	try {
697	>	int s = top, oldLen, len;
698	>	if ((a = array) == null)
699	>	a = array = new ForkJoinTask<?>[len=INITIAL_QUEUE_CAPACITY];
700	>	else if ((oldLen = a.length) > s + 1 - base)
701	>	len = oldLen;
702	>	else if ((len = oldLen << 1) > MAXIMUM_QUEUE_CAPACITY)
703	>	throw new RejectedExecutionException("Capacity exceeded");
704	>	else {
705	>	int oldMask, b;
706	>	ForkJoinTask<?>[] oldA = a;
707	>	a = array = new ForkJoinTask<?>[len];
708	>	if ((oldMask = oldLen - 1) >= 0 && s - (b = base) > 0) {
709	>	int mask = len - 1;
710	>	do {
711	>	ForkJoinTask<?> x;
712	>	int oldj = ((b & oldMask) << ASHIFT) + ABASE;
713	>	int j = ((b & mask) << ASHIFT) + ABASE;
714	>	x = (ForkJoinTask<?>)
715	>	U.getObjectVolatile(oldA, oldj);
716	>	if (x != null &&
717	>	U.compareAndSwapObject(oldA, oldj, x, null))
718	>	U.putObjectVolatile(a, j, x);
719	>	} while (++b != s);
720		}
711	–	} finally {
712	–	runState = 0; // unlock
721		}
722	+	U.putOrderedObject
723	+	(a, (((len - 1) & s) << ASHIFT) + ABASE, task);
724	+	top = s + 1;
725	+	} finally {
726	+	if (!owned)
727	+	qlock = 0;
728		}
729	<	return submitted;
729	>	if ((p = pool) != null)
730	>	p.signalWork(this, 1);
731	>	return true;
732		}
733
734		/**
735		* Takes next task, if one exists, in LIFO order. Call only
736	<	* by owner in unshared queues. (We do not have a shared
721	<	* version of this method because it is never needed.)
736	>	* by owner in unshared queues.
737		*/
738		final ForkJoinTask<?> pop() {
739		ForkJoinTask<?>[] a; ForkJoinTask<?> t; int m;
#	Line 773 \| Line 788 \| public class ForkJoinPool extends Abstra
788		else if (base == b) {
789		if (b + 1 == top)
790		break;
791	<	Thread.yield(); // wait for lagging update
791	>	Thread.yield(); // wait for lagging update (very rare)
792		}
793		}
794		return null;
#	Line 800 \| Line 815 \| public class ForkJoinPool extends Abstra
815
816		/**
817		* Pops the given task only if it is at the current top.
818	+	* (A shared version is available only via FJP.tryExternalUnpush)
819		*/
820		final boolean tryUnpush(ForkJoinTask<?> t) {
821		ForkJoinTask<?>[] a; int s;
#	Line 813 \| Line 829 \| public class ForkJoinPool extends Abstra
829		}
830
831		/**
816	–	* Polls the given task only if it is at the current base.
817	–	*/
818	–	final boolean pollFor(ForkJoinTask<?> task) {
819	–	ForkJoinTask<?>[] a; int b;
820	–	if ((b = base) - top < 0 && (a = array) != null) {
821	–	int j = (((a.length - 1) & b) << ASHIFT) + ABASE;
822	–	if (U.getObjectVolatile(a, j) == task && base == b &&
823	–	U.compareAndSwapObject(a, j, task, null)) {
824	–	base = b + 1;
825	–	return true;
826	–	}
827	–	}
828	–	return false;
829	–	}
830	–
831	–	/**
832	–	* Initializes or doubles the capacity of array. Call either
833	–	* by owner or with lock held -- it is OK for base, but not
834	–	* top, to move while resizings are in progress.
835	–	*
836	–	* @param rejectOnFailure if true, throw exception if capacity
837	–	* exceeded (relayed ultimately to user); else return null.
838	–	*/
839	–	final ForkJoinTask<?>[] growArray(boolean rejectOnFailure) {
840	–	ForkJoinTask<?>[] oldA = array;
841	–	int size = oldA != null ? oldA.length << 1 : INITIAL_QUEUE_CAPACITY;
842	–	if (size <= MAXIMUM_QUEUE_CAPACITY) {
843	–	int oldMask, t, b;
844	–	ForkJoinTask<?>[] a = array = new ForkJoinTask<?>[size];
845	–	if (oldA != null && (oldMask = oldA.length - 1) >= 0 &&
846	–	(t = top) - (b = base) > 0) {
847	–	int mask = size - 1;
848	–	do {
849	–	ForkJoinTask<?> x;
850	–	int oldj = ((b & oldMask) << ASHIFT) + ABASE;
851	–	int j = ((b & mask) << ASHIFT) + ABASE;
852	–	x = (ForkJoinTask<?>)U.getObjectVolatile(oldA, oldj);
853	–	if (x != null &&
854	–	U.compareAndSwapObject(oldA, oldj, x, null))
855	–	U.putObjectVolatile(a, j, x);
856	–	} while (++b != t);
857	–	}
858	–	return a;
859	–	}
860	–	else if (!rejectOnFailure)
861	–	return null;
862	–	else
863	–	throw new RejectedExecutionException("Queue capacity exceeded");
864	–	}
865	–
866	–	/**
832		* Removes and cancels all known tasks, ignoring any exceptions.
833		*/
834		final void cancelAll() {
#	Line 887 \| Line 852 \| public class ForkJoinPool extends Abstra
852		return seed = r ^= r << 5;
853		}
854
855	<	// Execution methods
855	>	/**
856	>	* Provides a more accurate estimate of size than (top - base)
857	>	* by ordering reads and checking whether a near-empty queue
858	>	* has at least one unclaimed task.
859	>	*/
860	>	final int queueSize() {
861	>	ForkJoinTask<?>[] a; int k, s, n;
862	>	return ((n = base - (s = top)) < 0 &&
863	>	(n != -1 \|\|
864	>	((a = array) != null && (k = a.length) > 0 &&
865	>	U.getObject
866	>	(a, (long)((((k - 1) & (s - 1)) << ASHIFT) + ABASE)) != null))) ?
867	>	-n : 0;
868	>	}
869	>
870	>	// Specialized execution methods
871
872		/**
873		* Pops and runs tasks until empty.
#	Line 916 \| Line 896 \| public class ForkJoinPool extends Abstra
896		}
897
898		/**
899	<	* If present, removes from queue and executes the given task, or
900	<	* any other cancelled task. Returns (true) immediately on any CAS
899	>	* If present, removes from queue and executes the given task,
900	>	* or any other cancelled task. Returns (true) on any CAS
901		* or consistency check failure so caller can retry.
902		*
903	<	* @return 0 if no progress can be made, else positive
924	<	* (this unusual convention simplifies use with tryHelpStealer.)
903	>	* @return false if no progress can be made, else true;
904		*/
905	<	final int tryRemoveAndExec(ForkJoinTask<?> task) {
906	<	int stat = 1;
928	<	boolean removed = false, empty = true;
905	>	final boolean tryRemoveAndExec(ForkJoinTask<?> task) {
906	>	boolean stat = true, removed = false, empty = true;
907		ForkJoinTask<?>[] a; int m, s, b, n;
908		if ((a = array) != null && (m = a.length - 1) >= 0 &&
909		(n = (s = top) - (b = base)) > 0) {
#	Line 955 \| Line 933 \| public class ForkJoinPool extends Abstra
933		}
934		if (--n == 0) {
935		if (!empty && base == b)
936	<	stat = 0;
936	>	stat = false;
937		break;
938		}
939		}
#	Line 966 \| Line 944 \| public class ForkJoinPool extends Abstra
944		}
945
946		/**
947	+	* Polls for and executes the given task or any other task in
948	+	* its CountedCompleter computation
949	+	*/
950	+	final boolean pollAndExecCC(ForkJoinTask<?> root) {
951	+	ForkJoinTask<?>[] a; int b; Object o;
952	+	outer: while ((b = base) - top < 0 && (a = array) != null) {
953	+	long j = (((a.length - 1) & b) << ASHIFT) + ABASE;
954	+	if ((o = U.getObject(a, j)) == null \|\|
955	+	!(o instanceof CountedCompleter))
956	+	break;
957	+	for (CountedCompleter<?> t = (CountedCompleter<?>)o, r = t;;) {
958	+	if (r == root) {
959	+	if (base == b &&
960	+	U.compareAndSwapObject(a, j, t, null)) {
961	+	base = b + 1;
962	+	t.doExec();
963	+	return true;
964	+	}
965	+	else
966	+	break; // restart
967	+	}
968	+	if ((r = r.completer) == null)
969	+	break outer; // not part of root computation
970	+	}
971	+	}
972	+	return false;
973	+	}
974	+
975	+	/**
976		* Executes a top-level task and any local tasks remaining
977		* after execution.
978		*/
979		final void runTask(ForkJoinTask<?> t) {
980		if (t != null) {
981	<	currentSteal = t;
982	<	t.doExec();
981	>	(currentSteal = t).doExec();
982	>	currentSteal = null;
983	>	if (++nsteals < 0) { // spill on overflow
984	>	ForkJoinPool p;
985	>	if ((p = pool) != null)
986	>	p.collectStealCount(this);
987	>	}
988		if (top != base) { // process remaining local tasks
989		if (mode == 0)
990		popAndExecAll();
991		else
992		pollAndExecAll();
993		}
982	–	++nsteals;
983	–	currentSteal = null;
994		}
995		}
996
#	Line 990 \| Line 1000 \| public class ForkJoinPool extends Abstra
1000		final void runSubtask(ForkJoinTask<?> t) {
1001		if (t != null) {
1002		ForkJoinTask<?> ps = currentSteal;
1003	<	currentSteal = t;
994	<	t.doExec();
1003	>	(currentSteal = t).doExec();
1004		currentSteal = ps;
1005		}
1006		}
#	Line 1026 \| Line 1035 \| public class ForkJoinPool extends Abstra
1035
1036		// Unsafe mechanics
1037		private static final sun.misc.Unsafe U;
1038	<	private static final long RUNSTATE;
1038	>	private static final long QLOCK;
1039		private static final int ABASE;
1040		private static final int ASHIFT;
1041		static {
#	Line 1035 \| Line 1044 \| public class ForkJoinPool extends Abstra
1044		U = getUnsafe();
1045		Class<?> k = WorkQueue.class;
1046		Class<?> ak = ForkJoinTask[].class;
1047	<	RUNSTATE = U.objectFieldOffset
1048	<	(k.getDeclaredField("runState"));
1047	>	QLOCK = U.objectFieldOffset
1048	>	(k.getDeclaredField("qlock"));
1049		ABASE = U.arrayBaseOffset(ak);
1050		s = U.arrayIndexScale(ak);
1051		} catch (Exception e) {
#	Line 1051 \| Line 1060 \| public class ForkJoinPool extends Abstra
1060		/**
1061		* Per-thread records for threads that submit to pools. Currently
1062		* holds only pseudo-random seed / index that is used to choose
1063	<	* submission queues in method doSubmit. In the future, this may
1063	>	* submission queues in method externalPush. In the future, this may
1064		* also incorporate a means to implement different task rejection
1065		* and resubmission policies.
1066		*
#	Line 1059 \| Line 1068 \| public class ForkJoinPool extends Abstra
1068		* the same way but are initialized and updated using slightly
1069		* different mechanics. Both are initialized using the same
1070		* approach as in class ThreadLocal, where successive values are
1071	<	* unlikely to collide with previous values. This is done during
1072	<	* registration for workers, but requires a separate AtomicInteger
1073	<	* for submitters. Seeds are then randomly modified upon
1065	<	* collisions using xorshifts, which requires a non-zero seed.
1071	>	* unlikely to collide with previous values. Seeds are then
1072	>	* randomly modified upon collisions using xorshifts, which
1073	>	* requires a non-zero seed.
1074		*/
1075		static final class Submitter {
1076		int seed;
1077	<	Submitter() {
1070	<	int s = nextSubmitterSeed.getAndAdd(SEED_INCREMENT);
1071	<	seed = (s == 0) ? 1 : s; // ensure non-zero
1072	<	}
1077	>	Submitter(int s) { seed = s; }
1078		}
1079
1080	<	/** ThreadLocal class for Submitters */
1081	<	static final class ThreadSubmitter extends ThreadLocal<Submitter> {
1082	<	public Submitter initialValue() { return new Submitter(); }
1078	<	}
1080	>	/** Property prefix for constructing common pool */
1081	>	private static final String propPrefix =
1082	>	"java.util.concurrent.ForkJoinPool.common.";
1083
1084		// static fields (initialized in static initializer below)
1085
#	Line 1087 \| Line 1091 \| public class ForkJoinPool extends Abstra
1091		defaultForkJoinWorkerThreadFactory;
1092
1093		/**
1094	<	* Generator for assigning sequence numbers as pool names.
1094	>	* Common (static) pool. Non-null for public use unless a static
1095	>	* construction exception, but internal usages null-check on use
1096	>	* to paranoically avoid potential initialization circularities
1097	>	* as well as to simplify generated code.
1098		*/
1099	<	private static final AtomicInteger poolNumberGenerator;
1093	<
1094	<	/**
1095	<	* Generator for initial hashes/seeds for submitters. Accessed by
1096	<	* Submitter class constructor.
1097	<	*/
1098	<	static final AtomicInteger nextSubmitterSeed;
1099	>	static final ForkJoinPool commonPool;
1100
1101		/**
1102		* Permission required for callers of methods that may start or
#	Line 1107 \| Line 1108 \| public class ForkJoinPool extends Abstra
1108		* Per-thread submission bookkeeping. Shared across all pools
1109		* to reduce ThreadLocal pollution and because random motion
1110		* to avoid contention in one pool is likely to hold for others.
1111	+	* Lazily initialized on first submission (but null-checked
1112	+	* in other contexts to avoid unnecessary initialization).
1113	+	*/
1114	+	static final ThreadLocal<Submitter> submitters;
1115	+
1116	+	/**
1117	+	* Common pool parallelism. Must equal commonPool.parallelism.
1118		*/
1119	<	private static final ThreadSubmitter submitters;
1119	>	static final int commonPoolParallelism;
1120	>
1121	>	/**
1122	>	* Sequence number for creating workerNamePrefix.
1123	>	*/
1124	>	private static int poolNumberSequence;
1125	>
1126	>	/**
1127	>	* Return the next sequence number. We don't expect this to
1128	>	* ever contend so use simple builtin sync.
1129	>	*/
1130	>	private static final synchronized int nextPoolId() {
1131	>	return ++poolNumberSequence;
1132	>	}
1133
1134		// static constants
1135
1136		/**
1137	<	* The wakeup interval (in nanoseconds) for a worker waiting for a
1138	<	* task when the pool is quiescent to instead try to shrink the
1139	<	* number of workers. The exact value does not matter too
1140	<	* much. It must be short enough to release resources during
1141	<	* sustained periods of idleness, but not so short that threads
1142	<	* are continually re-created.
1137	>	* Initial timeout value (in nanoseconds) for the thread
1138	>	* triggering quiescence to park waiting for new work. On timeout,
1139	>	* the thread will instead try to shrink the number of
1140	>	* workers. The value should be large enough to avoid overly
1141	>	* aggressive shrinkage during most transient stalls (long GCs
1142	>	* etc).
1143		*/
1144	<	private static final long SHRINK_RATE =
1124	<	4L * 1000L * 1000L * 1000L; // 4 seconds
1144	>	private static final long IDLE_TIMEOUT = 2000L * 1000L * 1000L; // 2sec
1145
1146		/**
1147	<	* The timeout value for attempted shrinkage, includes
1128	<	* some slop to cope with system timer imprecision.
1147	>	* Timeout value when there are more threads than parallelism level
1148		*/
1149	<	private static final long SHRINK_TIMEOUT = SHRINK_RATE - (SHRINK_RATE / 10);
1149	>	private static final long FAST_IDLE_TIMEOUT = 200L * 1000L * 1000L;
1150
1151		/**
1152		* The maximum stolen->joining link depth allowed in method
1153	<	* tryHelpStealer. Must be a power of two. This value also
1135	<	* controls the maximum number of times to try to help join a task
1136	<	* without any apparent progress or change in pool state before
1137	<	* giving up and blocking (see awaitJoin). Depths for legitimate
1153	>	* tryHelpStealer. Must be a power of two. Depths for legitimate
1154		* chains are unbounded, but we use a fixed constant to avoid
1155		* (otherwise unchecked) cycles and to bound staleness of
1156		* traversal parameters at the expense of sometimes blocking when
#	Line 1143 \| Line 1159 \| public class ForkJoinPool extends Abstra
1159		private static final int MAX_HELP = 64;
1160
1161		/**
1146	–	* Secondary time-based bound (in nanosecs) for helping attempts
1147	–	* before trying compensated blocking in awaitJoin. Used in
1148	–	* conjunction with MAX_HELP to reduce variance due to different
1149	–	* polling rates associated with different helping options. The
1150	–	* value should roughly approximate the time required to create
1151	–	* and/or activate a worker thread.
1152	–	*/
1153	–	private static final long COMPENSATION_DELAY = 1L << 18; // ~0.25 millisec
1154	–
1155	–	/**
1162		* Increment for seed generators. See class ThreadLocal for
1163		* explanation.
1164		*/
#	Line 1186 \| Line 1192 \| public class ForkJoinPool extends Abstra
1192		* scan for them to avoid queuing races. Note however that
1193		* eventCount updates lag releases so usage requires care.
1194		*
1195	<	* Field runState is an int packed with:
1195	>	* Field plock is an int packed with:
1196		* SHUTDOWN: true if shutdown is enabled (1 bit)
1197	<	* SEQ: a sequence number updated upon (de)registering workers (30 bits)
1198	<	* INIT: set true after workQueues array construction (1 bit)
1197	>	* SEQ: a sequence lock, with PL_LOCK bit set if locked (30 bits)
1198	>	* SIGNAL: set when threads may be waiting on the lock (1 bit)
1199		*
1200		* The sequence number enables simple consistency checks:
1201		* Staleness of read-only operations on the workQueues array can
1202	<	* be checked by comparing runState before vs after the reads.
1202	>	* be checked by comparing plock before vs after the reads.
1203		*/
1204
1205		// bit positions/shifts for fields
#	Line 1205 \| Line 1211 \| public class ForkJoinPool extends Abstra
1211		// bounds
1212		private static final int SMASK = 0xffff; // short bits
1213		private static final int MAX_CAP = 0x7fff; // max #workers - 1
1214	<	private static final int SQMASK = 0xfffe; // even short bits
1214	>	private static final int EVENMASK = 0xfffe; // even short bits
1215	>	private static final int SQMASK = 0x007e; // max 64 (even) slots
1216		private static final int SHORT_SIGN = 1 << 15;
1217		private static final int INT_SIGN = 1 << 31;
1218
#	Line 1230 \| Line 1237 \| public class ForkJoinPool extends Abstra
1237		private static final int E_MASK = 0x7fffffff; // no STOP_BIT
1238		private static final int E_SEQ = 1 << EC_SHIFT;
1239
1240	<	// runState bits
1240	>	// plock bits
1241		private static final int SHUTDOWN = 1 << 31;
1242	+	private static final int PL_LOCK = 2;
1243	+	private static final int PL_SIGNAL = 1;
1244	+	private static final int PL_SPINS = 1 << 8;
1245
1246		// access mode for WorkQueue
1247		static final int LIFO_QUEUE = 0;
#	Line 1246 \| Line 1256 \| public class ForkJoinPool extends Abstra
1256		* declaration order and may differ across JVMs, but the following
1257		* empirically works OK on current JVMs.
1258		*/
1259	<
1259	>	volatile long stealCount; // collects worker counts
1260		volatile long ctl; // main pool control
1261		final int parallelism; // parallelism level
1262		final int localMode; // per-worker scheduling mode
1263	<	final int submitMask; // submit queue index bound
1264	<	int nextSeed; // for initializing worker seeds
1255	<	volatile int runState; // shutdown status and seq
1263	>	volatile int indexSeed; // worker/submitter index seed
1264	>	volatile int plock; // shutdown status and seqLock
1265		WorkQueue[] workQueues; // main registry
1257	–	final Mutex lock; // for registration
1258	–	final Condition termination; // for awaitTermination
1266		final ForkJoinWorkerThreadFactory factory; // factory for new workers
1267		final Thread.UncaughtExceptionHandler ueh; // per-worker UEH
1261	–	final AtomicLong stealCount; // collect counts when terminated
1262	–	final AtomicInteger nextWorkerNumber; // to create worker name string
1268		final String workerNamePrefix; // to create worker name string
1269
1270	<	// Creating, registering, and deregistering workers
1271	<
1272	<	/**
1273	<	* Tries to create and start a worker
1274	<	*/
1275	<	private void addWorker() {
1276	<	Throwable ex = null;
1277	<	ForkJoinWorkerThread wt = null;
1278	<	try {
1279	<	if ((wt = factory.newThread(this)) != null) {
1280	<	wt.start();
1281	<	return;
1270	>	/*
1271	>	* Acquires the plock lock to protect worker array and related
1272	>	* updates. This method is called only if an initial CAS on plock
1273	>	* fails. This acts as a spinLock for normal cases, but falls back
1274	>	* to builtin monitor to block when (rarely) needed. This would be
1275	>	* a terrible idea for a highly contended lock, but works fine as
1276	>	* a more conservative alternative to a pure spinlock. See
1277	>	* internal ConcurrentHashMap documentation for further
1278	>	* explanation of nearly the same construction.
1279	>	*/
1280	>	private int acquirePlock() {
1281	>	int spins = PL_SPINS, r = 0, ps, nps;
1282	>	for (;;) {
1283	>	if (((ps = plock) & PL_LOCK) == 0 &&
1284	>	U.compareAndSwapInt(this, PLOCK, ps, nps = ps + PL_LOCK))
1285	>	return nps;
1286	>	else if (r == 0)
1287	>	r = ThreadLocalRandom.current().nextInt(); // randomize spins
1288	>	else if (spins >= 0) {
1289	>	r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
1290	>	if (r >= 0)
1291	>	--spins;
1292	>	}
1293	>	else if (U.compareAndSwapInt(this, PLOCK, ps, ps \| PL_SIGNAL)) {
1294	>	synchronized (this) {
1295	>	if ((plock & PL_SIGNAL) != 0) {
1296	>	try {
1297	>	wait();
1298	>	} catch (InterruptedException ie) {
1299	>	try {
1300	>	Thread.currentThread().interrupt();
1301	>	} catch (SecurityException ignore) {
1302	>	}
1303	>	}
1304	>	}
1305	>	else
1306	>	notifyAll();
1307	>	}
1308		}
1278	–	} catch (Throwable e) {
1279	–	ex = e;
1309		}
1281	–	deregisterWorker(wt, ex); // adjust counts etc on failure
1310		}
1311
1312		/**
1313	<	* Callback from ForkJoinWorkerThread constructor to assign a
1314	<	* public name. This must be separate from registerWorker because
1287	<	* it is called during the "super" constructor call in
1288	<	* ForkJoinWorkerThread.
1313	>	* Unlocks and signals any thread waiting for plock. Called only
1314	>	* when CAS of seq value for unlock fails.
1315		*/
1316	<	final String nextWorkerName() {
1317	<	return workerNamePrefix.concat
1318	<	(Integer.toString(nextWorkerNumber.addAndGet(1)));
1316	>	private void releasePlock(int ps) {
1317	>	plock = ps;
1318	>	synchronized (this) { notifyAll(); }
1319		}
1320
1321	+	// Registering and deregistering workers
1322	+
1323		/**
1324		* Callback from ForkJoinWorkerThread constructor to establish its
1325		* poolIndex and record its WorkQueue. To avoid scanning bias due
#	Line 1301 \| Line 1329 \| public class ForkJoinPool extends Abstra
1329		*
1330		* @param w the worker's queue
1331		*/
1304	–
1332		final void registerWorker(WorkQueue w) {
1333	<	Mutex lock = this.lock;
1334	<	lock.lock();
1333	>	int s, ps; // generate a rarely colliding candidate index seed
1334	>	do {} while (!U.compareAndSwapInt(this, INDEXSEED,
1335	>	s = indexSeed, s += SEED_INCREMENT) \|\|
1336	>	s == 0); // skip 0
1337	>	if (((ps = plock) & PL_LOCK) != 0 \|\|
1338	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1339	>	ps = acquirePlock();
1340	>	int nps = (ps & SHUTDOWN) \| ((ps + PL_LOCK) & ~SHUTDOWN);
1341		try {
1342	<	WorkQueue[] ws = workQueues;
1343	<	if (w != null && ws != null) { // skip on shutdown/failure
1344	<	int rs, n = ws.length, m = n - 1;
1345	<	int s = nextSeed += SEED_INCREMENT; // rarely-colliding sequence
1313	<	w.seed = (s == 0) ? 1 : s; // ensure non-zero seed
1342	>	WorkQueue[] ws;
1343	>	if (w != null && (ws = workQueues) != null) {
1344	>	w.seed = s;
1345	>	int n = ws.length, m = n - 1;
1346		int r = (s << 1) \| 1; // use odd-numbered indices
1347		if (ws[r &= m] != null) { // collision
1348		int probes = 0; // step by approx half size
1349	<	int step = (n <= 4) ? 2 : ((n >>> 1) & SQMASK) + 2;
1349	>	int step = (n <= 4) ? 2 : ((n >>> 1) & EVENMASK) + 2;
1350		while (ws[r = (r + step) & m] != null) {
1351		if (++probes >= n) {
1352		workQueues = ws = Arrays.copyOf(ws, n <<= 1);
#	Line 1324 \| Line 1356 \| public class ForkJoinPool extends Abstra
1356		}
1357		}
1358		w.eventCount = w.poolIndex = r; // establish before recording
1359	<	ws[r] = w; // also update seq
1328	<	runState = ((rs = runState) & SHUTDOWN) \| ((rs + 2) & ~SHUTDOWN);
1359	>	ws[r] = w;
1360		}
1361		} finally {
1362	<	lock.unlock();
1362	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1363	>	releasePlock(nps);
1364		}
1365		}
1366
1367		/**
1368		* Final callback from terminating worker, as well as upon failure
1369	<	* to construct or start a worker in addWorker. Removes record of
1370	<	* worker from array, and adjusts counts. If pool is shutting
1371	<	* down, tries to complete termination.
1369	>	* to construct or start a worker. Removes record of worker from
1370	>	* array, and adjusts counts. If pool is shutting down, tries to
1371	>	* complete termination.
1372		*
1373	<	* @param wt the worker thread or null if addWorker failed
1373	>	* @param wt the worker thread or null if construction failed
1374		* @param ex the exception causing failure, or null if none
1375		*/
1376		final void deregisterWorker(ForkJoinWorkerThread wt, Throwable ex) {
1345	–	Mutex lock = this.lock;
1377		WorkQueue w = null;
1378		if (wt != null && (w = wt.workQueue) != null) {
1379	<	w.runState = -1; // ensure runState is set
1380	<	stealCount.getAndAdd(w.totalSteals + w.nsteals);
1381	<	int idx = w.poolIndex;
1382	<	lock.lock();
1383	<	try { // remove record from array
1379	>	int ps;
1380	>	collectStealCount(w);
1381	>	w.qlock = -1; // ensure set
1382	>	if (((ps = plock) & PL_LOCK) != 0 \|\|
1383	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1384	>	ps = acquirePlock();
1385	>	int nps = (ps & SHUTDOWN) \| ((ps + PL_LOCK) & ~SHUTDOWN);
1386	>	try {
1387	>	int idx = w.poolIndex;
1388		WorkQueue[] ws = workQueues;
1389		if (ws != null && idx >= 0 && idx < ws.length && ws[idx] == w)
1390		ws[idx] = null;
1391		} finally {
1392	<	lock.unlock();
1392	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1393	>	releasePlock(nps);
1394		}
1395		}
1396
#	Line 1367 \| Line 1403 \| public class ForkJoinPool extends Abstra
1403		if (!tryTerminate(false, false) && w != null) {
1404		w.cancelAll(); // cancel remaining tasks
1405		if (w.array != null) // suppress signal if never ran
1406	<	signalWork(); // wake up or create replacement
1406	>	signalWork(null, 1); // wake up or create replacement
1407		if (ex == null) // help clean refs on way out
1408		ForkJoinTask.helpExpungeStaleExceptions();
1409		}
1410
1411		if (ex != null) // rethrow
1412	<	U.throwException(ex);
1412	>	ForkJoinTask.rethrow(ex);
1413		}
1414
1415	+	/**
1416	+	* Collect worker steal count into total. Called on termination
1417	+	* and upon int overflow of local count. (There is a possible race
1418	+	* in the latter case vs any caller of getStealCount, which can
1419	+	* make its results less accurate than usual.)
1420	+	*/
1421	+	final void collectStealCount(WorkQueue w) {
1422	+	if (w != null) {
1423	+	long sc;
1424	+	int ns = w.nsteals;
1425	+	w.nsteals = 0; // handle overflow
1426	+	long steals = (ns >= 0) ? ns : 1L + (long)(Integer.MAX_VALUE);
1427	+	do {} while (!U.compareAndSwapLong(this, STEALCOUNT,
1428	+	sc = stealCount, sc + steals));
1429	+	}
1430	+	}
1431
1432		// Submissions
1433
1434		/**
1435		* Unless shutting down, adds the given task to a submission queue
1436		* at submitter's current queue index (modulo submission
1437	<	* range). If no queue exists at the index, one is created. If
1438	<	* the queue is busy, another index is randomly chosen. The
1387	<	* submitMask bounds the effective number of queues to the
1388	<	* (nearest power of two for) parallelism level.
1437	>	* range). Only the most common path is directly handled in this
1438	>	* method. All others are relayed to fullExternalPush.
1439		*
1440		* @param task the task. Caller must ensure non-null.
1441		*/
1442	<	private void doSubmit(ForkJoinTask<?> task) {
1443	<	Submitter s = submitters.get();
1444	<	for (int r = s.seed, m = submitMask;;) {
1445	<	WorkQueue[] ws; WorkQueue q;
1446	<	int k = r & m & SQMASK; // use only even indices
1447	<	if (runState < 0 \|\| (ws = workQueues) == null \|\| ws.length <= k)
1448	<	throw new RejectedExecutionException(); // shutting down
1449	<	else if ((q = ws[k]) == null) { // create new queue
1450	<	WorkQueue nq = new WorkQueue(this, null, SHARED_QUEUE);
1451	<	Mutex lock = this.lock; // construct outside lock
1452	<	lock.lock();
1453	<	try { // recheck under lock
1454	<	int rs = runState; // to update seq
1455	<	if (ws == workQueues && ws[k] == null) {
1406	<	ws[k] = nq;
1407	<	runState = ((rs & SHUTDOWN) \| ((rs + 2) & ~SHUTDOWN));
1408	<	}
1409	<	} finally {
1410	<	lock.unlock();
1411	<	}
1412	<	}
1413	<	else if (q.trySharedPush(task)) {
1414	<	signalWork();
1442	>	final void externalPush(ForkJoinTask<?> task) {
1443	>	WorkQueue[] ws; WorkQueue q; Submitter z; int m; ForkJoinTask<?>[] a;
1444	>	if ((z = submitters.get()) != null && plock > 0 &&
1445	>	(ws = workQueues) != null && (m = (ws.length - 1)) >= 0 &&
1446	>	(q = ws[m & z.seed & SQMASK]) != null &&
1447	>	U.compareAndSwapInt(q, QLOCK, 0, 1)) { // lock
1448	>	int s = q.top, n;
1449	>	if ((a = q.array) != null && a.length > (n = s + 1 - q.base)) {
1450	>	U.putObject(a, (long)(((a.length - 1) & s) << ASHIFT) + ABASE,
1451	>	task);
1452	>	q.top = s + 1; // push on to deque
1453	>	q.qlock = 0;
1454	>	if (n <= 1)
1455	>	signalWork(q, 1);
1456		return;
1457		}
1458	<	else if (m > 1) { // move to a different index
1458	>	q.qlock = 0;
1459	>	}
1460	>	fullExternalPush(task);
1461	>	}
1462	>
1463	>	/**
1464	>	* Full version of externalPush. This method is called, among
1465	>	* other times, upon the first submission of the first task to the
1466	>	* pool, so must perform secondary initialization: creating
1467	>	* workQueue array and setting plock to a valid value. It also
1468	>	* detects first submission by an external thread by looking up
1469	>	* its ThreadLocal, and creates a new shared queue if the one at
1470	>	* index if empty or contended. The lock bodies must be
1471	>	* exception-free (so no try/finally) so we optimistically
1472	>	* allocate new queues/arrays outside the locks and throw them
1473	>	* away if (very rarely) not needed. Note that the plock seq value
1474	>	* can eventually wrap around zero, but if so harmlessly fails to
1475	>	* reinitialize.
1476	>	*/
1477	>	private void fullExternalPush(ForkJoinTask<?> task) {
1478	>	for (Submitter z = null;;) {
1479	>	WorkQueue[] ws; WorkQueue q; int ps, m, r, s;
1480	>	if ((ps = plock) < 0)
1481	>	throw new RejectedExecutionException();
1482	>	else if ((ws = workQueues) == null \|\| (m = ws.length - 1) < 0) {
1483	>	int n = parallelism - 1; n \|= n >>> 1; n \|= n >>> 2;
1484	>	n \|= n >>> 4; n \|= n >>> 8; n \|= n >>> 16;
1485	>	WorkQueue[] nws = new WorkQueue[(n + 1) << 1]; // power of two
1486	>	if ((ps & PL_LOCK) != 0 \|\|
1487	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1488	>	ps = acquirePlock();
1489	>	if ((ws = workQueues) == null)
1490	>	workQueues = nws;
1491	>	int nps = (ps & SHUTDOWN) \| ((ps + PL_LOCK) & ~SHUTDOWN);
1492	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1493	>	releasePlock(nps);
1494	>	}
1495	>	else if (z == null && (z = submitters.get()) == null) {
1496	>	if (U.compareAndSwapInt(this, INDEXSEED,
1497	>	s = indexSeed, s += SEED_INCREMENT) &&
1498	>	s != 0) // skip 0
1499	>	submitters.set(z = new Submitter(s));
1500	>	}
1501	>	else {
1502	>	int k = (r = z.seed) & m & SQMASK;
1503	>	if ((q = ws[k]) == null && (ps & PL_LOCK) == 0) {
1504	>	(q = new WorkQueue(this, null, SHARED_QUEUE)).poolIndex = k;
1505	>	if (((ps = plock) & PL_LOCK) != 0 \|\|
1506	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1507	>	ps = acquirePlock();
1508	>	WorkQueue w = null;
1509	>	if ((ws = workQueues) != null && k < ws.length &&
1510	>	(w = ws[k]) == null)
1511	>	ws[k] = q;
1512	>	else
1513	>	q = w;
1514	>	int nps = (ps & SHUTDOWN) \| ((ps + PL_LOCK) & ~SHUTDOWN);
1515	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1516	>	releasePlock(nps);
1517	>	}
1518	>	if (q != null && q.qlock == 0 && q.fullPush(task, false))
1519	>	return;
1520		r ^= r << 13; // same xorshift as WorkQueues
1521		r ^= r >>> 17;
1522	<	s.seed = r ^= r << 5;
1522	>	z.seed = r ^= r << 5; // move to a different index
1523		}
1422	–	else
1423	–	Thread.yield(); // yield if no alternatives
1524		}
1525		}
1526
#	Line 1435 \| Line 1535 \| public class ForkJoinPool extends Abstra
1535		}
1536
1537		/**
1538	<	* Tries to activate or create a worker if too few are active.
1539	<	*/
1540	<	final void signalWork() {
1541	<	long c; int u;
1542	<	while ((u = (int)((c = ctl) >>> 32)) < 0) { // too few active
1543	<	WorkQueue[] ws = workQueues; int e, i; WorkQueue w; Thread p;
1544	<	if ((e = (int)c) > 0) { // at least one waiting
1545	<	if (ws != null && (i = e & SMASK) < ws.length &&
1538	>	* Tries to create (at most one) or activate (possibly several)
1539	>	* workers if too few are active. On contention failure, continues
1540	>	* until at least one worker is signalled or the given queue is
1541	>	* empty or all workers are active.
1542	>	*
1543	>	* @param q if non-null, the queue holding tasks to be signalled
1544	>	* @param signals the target number of signals.
1545	>	*/
1546	>	final void signalWork(WorkQueue q, int signals) {
1547	>	long c; int e, u, i; WorkQueue[] ws; WorkQueue w; Thread p;
1548	>	while ((u = (int)((c = ctl) >>> 32)) < 0) {
1549	>	if ((e = (int)c) > 0) {
1550	>	if ((ws = workQueues) != null && ws.length > (i = e & SMASK) &&
1551		(w = ws[i]) != null && w.eventCount == (e \| INT_SIGN)) {
1552		long nc = (((long)(w.nextWait & E_MASK)) \|
1553		((long)(u + UAC_UNIT) << 32));
1554		if (U.compareAndSwapLong(this, CTL, c, nc)) {
1555		w.eventCount = (e + E_SEQ) & E_MASK;
1556		if ((p = w.parker) != null)
1557	<	U.unpark(p); // activate and release
1558	<	break;
1557	>	U.unpark(p);
1558	>	if (--signals <= 0)
1559	>	break;
1560		}
1561	+	else
1562	+	signals = 1;
1563	+	if ((q != null && q.queueSize() == 0))
1564	+	break;
1565		}
1566		else
1567		break;
1568		}
1569	<	else if (e == 0 && (u & SHORT_SIGN) != 0) { // too few total
1569	>	else if (e == 0 && (u & SHORT_SIGN) != 0) {
1570		long nc = (long)(((u + UTC_UNIT) & UTC_MASK) \|
1571		((u + UAC_UNIT) & UAC_MASK)) << 32;
1572		if (U.compareAndSwapLong(this, CTL, c, nc)) {
1573	<	addWorker();
1573	>	ForkJoinWorkerThread wt = null;
1574	>	Throwable ex = null;
1575	>	boolean started = false;
1576	>	try {
1577	>	ForkJoinWorkerThreadFactory fac;
1578	>	if ((fac = factory) != null &&
1579	>	(wt = fac.newThread(this)) != null) {
1580	>	wt.start();
1581	>	started = true;
1582	>	}
1583	>	} catch (Throwable rex) {
1584	>	ex = rex;
1585	>	}
1586	>	if (!started)
1587	>	deregisterWorker(wt, ex); // adjust counts on failure
1588		break;
1589		}
1590		}
#	Line 1475 \| Line 1599 \| public class ForkJoinPool extends Abstra
1599		* Top-level runloop for workers, called by ForkJoinWorkerThread.run.
1600		*/
1601		final void runWorker(WorkQueue w) {
1602	<	w.growArray(false); // initialize queue array in this thread
1603	<	do { w.runTask(scan(w)); } while (w.runState >= 0);
1602	>	// initialize queue array in this thread
1603	>	w.array = new ForkJoinTask<?>[WorkQueue.INITIAL_QUEUE_CAPACITY];
1604	>	do { w.runTask(scan(w)); } while (w.qlock >= 0);
1605		}
1606
1607		/**
#	Line 1492 \| Line 1617 \| public class ForkJoinPool extends Abstra
1617		* relative prime, checking each at least once). The scan
1618		* terminates upon either finding a non-empty queue, or completing
1619		* the sweep. If the worker is not inactivated, it takes and
1620	<	* returns a task from this queue. On failure to find a task, we
1620	>	* returns a task from this queue. Otherwise, if not activated, it
1621	>	* signals workers (that may include itself) and returns so caller
1622	>	* can retry. Also returns for trtry if the worker array may have
1623	>	* changed during an empty scan. On failure to find a task, we
1624		* take one of the following actions, after which the caller will
1625		* retry calling this method unless terminated.
1626		*
1627		* * If pool is terminating, terminate the worker.
1628		*
1501	–	* * If not a complete sweep, try to release a waiting worker. If
1502	–	* the scan terminated because the worker is inactivated, then the
1503	–	* released worker will often be the calling worker, and it can
1504	–	* succeed obtaining a task on the next call. Or maybe it is
1505	–	* another worker, but with same net effect. Releasing in other
1506	–	* cases as well ensures that we have enough workers running.
1507	–	*
1629		* * If not already enqueued, try to inactivate and enqueue the
1630		* worker on wait queue. Or, if inactivating has caused the pool
1631		* to be quiescent, relay to idleAwaitWork to check for
1632		* termination and possibly shrink pool.
1633		*
1634	<	* * If already inactive, and the caller has run a task since the
1635	<	* last empty scan, return (to allow rescan) unless others are
1636	<	* also inactivated. Field WorkQueue.rescans counts down on each
1516	<	* scan to ensure eventual inactivation and blocking.
1517	<	*
1518	<	* * If already enqueued and none of the above apply, park
1519	<	* awaiting signal,
1634	>	* * If already enqueued and none of the above apply, possibly
1635	>	* (with 1/2 probability) park awaiting signal, else lingering to
1636	>	* help scan and signal.
1637		*
1638		* @param w the worker (via its WorkQueue)
1639	<	* @return a task or null of none found
1639	>	* @return a task or null if none found
1640		*/
1641		private final ForkJoinTask<?> scan(WorkQueue w) {
1642	<	WorkQueue[] ws; // first update random seed
1642	>	WorkQueue[] ws; WorkQueue q; // first update random seed
1643		int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
1644	<	int rs = runState, m; // volatile read order matters
1644	>	int ps = plock, m; // volatile read order matters
1645		if ((ws = workQueues) != null && (m = ws.length - 1) > 0) {
1646	<	int ec = w.eventCount; // ec is negative if inactive
1647	<	int step = (r >>> 16) \| 1; // relative prime
1648	<	for (int j = (m + 1) << 2; ; r += step) {
1649	<	WorkQueue q; ForkJoinTask<?> t; ForkJoinTask<?>[] a; int b;
1646	>	int ec = w.eventCount; // ec is negative if inactive
1647	>	int step = (r >>> 16) \| 1; // relatively prime
1648	>	for (int j = (m + 1) << 2; ; --j, r += step) {
1649	>	ForkJoinTask<?> t; ForkJoinTask<?>[] a; int b, n;
1650		if ((q = ws[r & m]) != null && (b = q.base) - q.top < 0 &&
1651	<	(a = q.array) != null) { // probably nonempty
1651	>	(a = q.array) != null) { // probably nonempty
1652		int i = (((a.length - 1) & b) << ASHIFT) + ABASE;
1653		t = (ForkJoinTask<?>)U.getObjectVolatile(a, i);
1654		if (q.base == b && ec >= 0 && t != null &&
1655		U.compareAndSwapObject(a, i, t, null)) {
1656	<	if (q.top - (q.base = b + 1) > 1)
1657	<	signalWork(); // help pushes signal
1658	<	return t;
1659	<	}
1660	<	else if (ec < 0 \|\| j <= m) {
1661	<	rs = 0; // mark scan as imcomplete
1662	<	break; // caller can retry after release
1656	>	if ((n = q.top - (q.base = b + 1)) > 0)
1657	>	signalWork(q, n);
1658	>	return t; // taken
1659	>	}
1660	>	if (j < m \|\| (ec < 0 && (ec = w.eventCount) < 0)) {
1661	>	if ((n = q.queueSize() - 1) > 0)
1662	>	signalWork(q, n);
1663	>	break; // let caller retry after signal
1664		}
1665		}
1666	<	if (--j < 0)
1667	<	break;
1668	<	}
1669	<
1670	<	long c = ctl; int e = (int)c, a = (int)(c >> AC_SHIFT), nr, ns;
1671	<	if (e < 0) // decode ctl on empty scan
1672	<	w.runState = -1; // pool is terminating
1673	<	else if (rs == 0 \|\| rs != runState) { // incomplete scan
1674	<	WorkQueue v; Thread p; // try to release a waiter
1675	<	if (e > 0 && a < 0 && w.eventCount == ec &&
1676	<	(v = ws[e & m]) != null && v.eventCount == (e \| INT_SIGN)) {
1677	<	long nc = ((long)(v.nextWait & E_MASK) \|
1678	<	((c + AC_UNIT) & (AC_MASK\|TC_MASK)));
1679	<	if (ctl == c && U.compareAndSwapLong(this, CTL, c, nc)) {
1680	<	v.eventCount = (e + E_SEQ) & E_MASK;
1681	<	if ((p = v.parker) != null)
1682	<	U.unpark(p);
1666	>	else if (j < 0) { // end of scan
1667	>	long c = ctl; int e;
1668	>	if (plock != ps) // incomplete sweep
1669	>	break;
1670	>	if ((e = (int)c) < 0) // pool is terminating
1671	>	w.qlock = -1;
1672	>	else if (ec >= 0) { // try to enqueue/inactivate
1673	>	long nc = ((long)ec \|
1674	>	((c - AC_UNIT) & (AC_MASK\|TC_MASK)));
1675	>	w.nextWait = e;
1676	>	w.eventCount = ec \| INT_SIGN; // mark as inactive
1677	>	if (ctl != c \|\|
1678	>	!U.compareAndSwapLong(this, CTL, c, nc))
1679	>	w.eventCount = ec; // unmark on CAS failure
1680	>	else if ((int)(c >> AC_SHIFT) == 1 - parallelism)
1681	>	idleAwaitWork(w, nc, c); // quiescent
1682	>	}
1683	>	else if (w.seed >= 0 && w.eventCount < 0) {
1684	>	Thread wt = Thread.currentThread();
1685	>	Thread.interrupted(); // clear status
1686	>	U.putObject(wt, PARKBLOCKER, this);
1687	>	w.parker = wt; // emulate LockSupport.park
1688	>	if (w.eventCount < 0) // recheck
1689	>	U.park(false, 0L);
1690	>	w.parker = null;
1691	>	U.putObject(wt, PARKBLOCKER, null);
1692		}
1693	<	}
1567	<	}
1568	<	else if (ec >= 0) { // try to enqueue/inactivate
1569	<	long nc = (long)ec \| ((c - AC_UNIT) & (AC_MASK\|TC_MASK));
1570	<	w.nextWait = e;
1571	<	w.eventCount = ec \| INT_SIGN; // mark as inactive
1572	<	if (ctl != c \|\| !U.compareAndSwapLong(this, CTL, c, nc))
1573	<	w.eventCount = ec; // unmark on CAS failure
1574	<	else {
1575	<	if ((ns = w.nsteals) != 0) {
1576	<	w.nsteals = 0; // set rescans if ran task
1577	<	w.rescans = (a > 0) ? 0 : a + parallelism;
1578	<	w.totalSteals += ns;
1579	<	}
1580	<	if (a == 1 - parallelism) // quiescent
1581	<	idleAwaitWork(w, nc, c);
1582	<	}
1583	<	}
1584	<	else if (w.eventCount < 0) { // already queued
1585	<	if ((nr = w.rescans) > 0) { // continue rescanning
1586	<	int ac = a + parallelism;
1587	<	if (((w.rescans = (ac < nr) ? ac : nr - 1) & 3) == 0)
1588	<	Thread.yield(); // yield before block
1589	<	}
1590	<	else {
1591	<	Thread.interrupted(); // clear status
1592	<	Thread wt = Thread.currentThread();
1593	<	U.putObject(wt, PARKBLOCKER, this);
1594	<	w.parker = wt; // emulate LockSupport.park
1595	<	if (w.eventCount < 0) // recheck
1596	<	U.park(false, 0L);
1597	<	w.parker = null;
1598	<	U.putObject(wt, PARKBLOCKER, null);
1693	>	break;
1694		}
1695		}
1696		}
#	Line 1605 \| Line 1700 \| public class ForkJoinPool extends Abstra
1700		/**
1701		* If inactivating worker w has caused the pool to become
1702		* quiescent, checks for pool termination, and, so long as this is
1703	<	* not the only worker, waits for event for up to SHRINK_RATE
1704	<	* nanosecs. On timeout, if ctl has not changed, terminates the
1703	>	* not the only worker, waits for event for up to a given
1704	>	* duration. On timeout, if ctl has not changed, terminates the
1705		* worker, which will in turn wake up another worker to possibly
1706		* repeat this process.
1707		*
#	Line 1615 \| Line 1710 \| public class ForkJoinPool extends Abstra
1710		* @param prevCtl the ctl value to restore if thread is terminated
1711		*/
1712		private void idleAwaitWork(WorkQueue w, long currentCtl, long prevCtl) {
1713	<	if (w.eventCount < 0 && !tryTerminate(false, false) &&
1714	<	(int)prevCtl != 0 && !hasQueuedSubmissions() && ctl == currentCtl) {
1713	>	if (w.eventCount < 0 &&
1714	>	(this == commonPool \|\| !tryTerminate(false, false)) &&
1715	>	(int)prevCtl != 0) {
1716	>	int dc = -(short)(currentCtl >>> TC_SHIFT);
1717	>	long parkTime = dc < 0 ? FAST_IDLE_TIMEOUT: (dc + 1) * IDLE_TIMEOUT;
1718	>	long deadline = System.nanoTime() + parkTime - 100000L; // 1ms slop
1719		Thread wt = Thread.currentThread();
1621	–	Thread.yield(); // yield before block
1720		while (ctl == currentCtl) {
1623	–	long startTime = System.nanoTime();
1721		Thread.interrupted(); // timed variant of version in scan()
1722		U.putObject(wt, PARKBLOCKER, this);
1723		w.parker = wt;
1724		if (ctl == currentCtl)
1725	<	U.park(false, SHRINK_RATE);
1725	>	U.park(false, parkTime);
1726		w.parker = null;
1727		U.putObject(wt, PARKBLOCKER, null);
1728		if (ctl != currentCtl)
1729		break;
1730	<	if (System.nanoTime() - startTime >= SHRINK_TIMEOUT &&
1730	>	if (deadline - System.nanoTime() <= 0L &&
1731		U.compareAndSwapLong(this, CTL, currentCtl, prevCtl)) {
1732		w.eventCount = (w.eventCount + E_SEQ) \| E_MASK;
1733	<	w.runState = -1; // shrink
1733	>	w.qlock = -1; // shrink
1734		break;
1735		}
1736		}
#	Line 1641 \| Line 1738 \| public class ForkJoinPool extends Abstra
1738		}
1739
1740		/**
1741	+	* Scans through queues looking for work while joining a task;
1742	+	* if any are present, signals.
1743	+	*
1744	+	* @param task to return early if done
1745	+	* @param origin an index to start scan
1746	+	*/
1747	+	final int helpSignal(ForkJoinTask<?> task, int origin) {
1748	+	WorkQueue[] ws; WorkQueue q; int m, n, s;
1749	+	if (task != null && (ws = workQueues) != null &&
1750	+	(m = ws.length - 1) >= 0) {
1751	+	for (int i = 0; i <= m; ++i) {
1752	+	if ((s = task.status) < 0)
1753	+	return s;
1754	+	if ((q = ws[(i + origin) & m]) != null &&
1755	+	(n = q.queueSize()) > 0) {
1756	+	signalWork(q, n);
1757	+	if ((int)(ctl >> AC_SHIFT) >= 0)
1758	+	break;
1759	+	}
1760	+	}
1761	+	}
1762	+	return 0;
1763	+	}
1764	+
1765	+	/**
1766		* Tries to locate and execute tasks for a stealer of the given
1767		* task, or in turn one of its stealers, Traces currentSteal ->
1768		* currentJoin links looking for a thread working on a descendant
#	Line 1727 \| Line 1849 \| public class ForkJoinPool extends Abstra
1849		}
1850
1851		/**
1852	<	* If task is at base of some steal queue, steals and executes it.
1852	>	* Analog of tryHelpStealer for CountedCompleters. Tries to steal
1853	>	* and run tasks within the target's computation.
1854	>	*
1855	>	* @param task the task to join
1856	>	* @param mode if shared, exit upon completing any task
1857	>	* if all workers are active
1858		*
1732	–	* @param joiner the joining worker
1733	–	* @param task the task
1859		*/
1860	<	private void tryPollForAndExec(WorkQueue joiner, ForkJoinTask<?> task) {
1861	<	WorkQueue[] ws;
1862	<	if ((ws = workQueues) != null) {
1863	<	for (int j = 1; j < ws.length && task.status >= 0; j += 2) {
1864	<	WorkQueue q = ws[j];
1865	<	if (q != null && q.pollFor(task)) {
1866	<	joiner.runSubtask(task);
1867	<	break;
1860	>	private int helpComplete(ForkJoinTask<?> task, int mode) {
1861	>	WorkQueue[] ws; WorkQueue q; int m, n, s;
1862	>	if (task != null && (ws = workQueues) != null &&
1863	>	(m = ws.length - 1) >= 0) {
1864	>	for (int j = 1, origin = j;;) {
1865	>	if ((s = task.status) < 0)
1866	>	return s;
1867	>	if ((q = ws[j & m]) != null && q.pollAndExecCC(task)) {
1868	>	origin = j;
1869	>	if (mode == SHARED_QUEUE && (int)(ctl >> AC_SHIFT) >= 0)
1870	>	break;
1871		}
1872	+	else if ((j = (j + 2) & m) == origin)
1873	+	break;
1874		}
1875		}
1876	+	return 0;
1877		}
1878
1879		/**
1880		* Tries to decrement active count (sometimes implicitly) and
1881		* possibly release or create a compensating worker in preparation
1882		* for blocking. Fails on contention or termination. Otherwise,
1883	<	* adds a new thread if no idle workers are available and either
1884	<	* pool would become completely starved or: (at least half
1754	<	* starved, and fewer than 50% spares exist, and there is at least
1755	<	* one task apparently available). Even though the availability
1756	<	* check requires a full scan, it is worthwhile in reducing false
1757	<	* alarms.
1758	<	*
1759	<	* @param task if non-null, a task being waited for
1760	<	* @param blocker if non-null, a blocker being waited for
1761	<	* @return true if the caller can block, else should recheck and retry
1883	>	* adds a new thread if no idle workers are available and pool
1884	>	* may become starved.
1885		*/
1886	<	final boolean tryCompensate(ForkJoinTask<?> task, ManagedBlocker blocker) {
1887	<	int pc = parallelism, e;
1888	<	long c = ctl;
1889	<	WorkQueue[] ws = workQueues;
1890	<	if ((e = (int)c) >= 0 && ws != null) {
1891	<	int u, a, ac, hc;
1892	<	int tc = (short)((u = (int)(c >>> 32)) >>> UTC_SHIFT) + pc;
1893	<	boolean replace = false;
1894	<	if ((a = u >> UAC_SHIFT) <= 0) {
1895	<	if ((ac = a + pc) <= 1)
1896	<	replace = true;
1897	<	else if ((e > 0 \|\| (task != null &&
1898	<	ac <= (hc = pc >>> 1) && tc < pc + hc))) {
1776	<	WorkQueue w;
1777	<	for (int j = 0; j < ws.length; ++j) {
1778	<	if ((w = ws[j]) != null && !w.isEmpty()) {
1779	<	replace = true;
1780	<	break; // in compensation range and tasks available
1781	<	}
1782	<	}
1886	>	final boolean tryCompensate() {
1887	>	int pc = parallelism, e, u, i, tc; long c;
1888	>	WorkQueue[] ws; WorkQueue w; Thread p;
1889	>	if ((e = (int)(c = ctl)) >= 0 && (ws = workQueues) != null) {
1890	>	if (e != 0 && (i = e & SMASK) < ws.length &&
1891	>	(w = ws[i]) != null && w.eventCount == (e \| INT_SIGN)) {
1892	>	long nc = ((long)(w.nextWait & E_MASK) \|
1893	>	(c & (AC_MASK\|TC_MASK)));
1894	>	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1895	>	w.eventCount = (e + E_SEQ) & E_MASK;
1896	>	if ((p = w.parker) != null)
1897	>	U.unpark(p);
1898	>	return true; // replace with idle worker
1899		}
1900		}
1901	<	if ((task == null \|\| task.status >= 0) && // recheck need to block
1902	<	(blocker == null \|\| !blocker.isReleasable()) && ctl == c) {
1903	<	if (!replace) { // no compensation
1904	<	long nc = ((c - AC_UNIT) & AC_MASK) \| (c & ~AC_MASK);
1905	<	if (U.compareAndSwapLong(this, CTL, c, nc))
1906	<	return true;
1907	<	}
1908	<	else if (e != 0) { // release an idle worker
1909	<	WorkQueue w; Thread p; int i;
1910	<	if ((i = e & SMASK) < ws.length && (w = ws[i]) != null) {
1911	<	long nc = ((long)(w.nextWait & E_MASK) \|
1912	<	(c & (AC_MASK\|TC_MASK)));
1913	<	if (w.eventCount == (e \| INT_SIGN) &&
1914	<	U.compareAndSwapLong(this, CTL, c, nc)) {
1915	<	w.eventCount = (e + E_SEQ) & E_MASK;
1916	<	if ((p = w.parker) != null)
1801	<	U.unpark(p);
1901	>	else if ((short)((u = (int)(c >>> 32)) >>> UTC_SHIFT) >= 0 &&
1902	>	(u >> UAC_SHIFT) + pc > 1) {
1903	>	long nc = ((c - AC_UNIT) & AC_MASK) \| (c & ~AC_MASK);
1904	>	if (U.compareAndSwapLong(this, CTL, c, nc))
1905	>	return true; // no compensation
1906	>	}
1907	>	else if ((tc = u + pc) < MAX_CAP) {
1908	>	long nc = ((c + TC_UNIT) & TC_MASK) \| (c & ~TC_MASK);
1909	>	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1910	>	Throwable ex = null;
1911	>	ForkJoinWorkerThread wt = null;
1912	>	try {
1913	>	ForkJoinWorkerThreadFactory fac;
1914	>	if ((fac = factory) != null &&
1915	>	(wt = fac.newThread(this)) != null) {
1916	>	wt.start();
1917		return true;
1918		}
1919	+	} catch (Throwable rex) {
1920	+	ex = rex;
1921		}
1922	<	}
1806	<	else if (tc < MAX_CAP) { // create replacement
1807	<	long nc = ((c + TC_UNIT) & TC_MASK) \| (c & ~TC_MASK);
1808	<	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1809	<	addWorker();
1810	<	return true;
1811	<	}
1922	>	deregisterWorker(wt, ex); // adjust counts etc
1923		}
1924		}
1925		}
#	Line 1823 \| Line 1934 \| public class ForkJoinPool extends Abstra
1934		* @return task status on exit
1935		*/
1936		final int awaitJoin(WorkQueue joiner, ForkJoinTask<?> task) {
1937	<	int s;
1938	<	if ((s = task.status) >= 0) {
1937	>	int s = 0;
1938	>	if (joiner != null && task != null && (s = task.status) >= 0) {
1939		ForkJoinTask<?> prevJoin = joiner.currentJoin;
1940		joiner.currentJoin = task;
1941	<	long startTime = 0L;
1942	<	for (int k = 0;;) {
1943	<	if ((s = (joiner.isEmpty() ? // try to help
1944	<	tryHelpStealer(joiner, task) :
1945	<	joiner.tryRemoveAndExec(task))) == 0 &&
1946	<	(s = task.status) >= 0) {
1947	<	if (k == 0) {
1948	<	startTime = System.nanoTime();
1949	<	tryPollForAndExec(joiner, task); // check uncommon case
1950	<	}
1951	<	else if ((k & (MAX_HELP - 1)) == 0 &&
1952	<	System.nanoTime() - startTime >=
1953	<	COMPENSATION_DELAY &&
1954	<	tryCompensate(task, null)) {
1955	<	if (task.trySetSignal()) {
1956	<	synchronized (task) {
1957	<	if (task.status >= 0) {
1847	<	try { // see ForkJoinTask
1848	<	task.wait(); // for explanation
1849	<	} catch (InterruptedException ie) {
1850	<	}
1941	>	do {} while ((s = task.status) >= 0 &&
1942	>	joiner.queueSize() > 0 &&
1943	>	joiner.tryRemoveAndExec(task)); // process local tasks
1944	>	if (s >= 0 && (s = task.status) >= 0 &&
1945	>	(s = helpSignal(task, joiner.poolIndex)) >= 0 &&
1946	>	(task instanceof CountedCompleter))
1947	>	s = helpComplete(task, LIFO_QUEUE);
1948	>	while (s >= 0 && (s = task.status) >= 0) {
1949	>	if ((joiner.queueSize() > 0 \|\| // try helping
1950	>	(s = tryHelpStealer(joiner, task)) == 0) &&
1951	>	(s = task.status) >= 0 && tryCompensate()) {
1952	>	if (task.trySetSignal() && (s = task.status) >= 0) {
1953	>	synchronized (task) {
1954	>	if (task.status >= 0) {
1955	>	try { // see ForkJoinTask
1956	>	task.wait(); // for explanation
1957	>	} catch (InterruptedException ie) {
1958		}
1852	–	else
1853	–	task.notifyAll();
1959		}
1960	+	else
1961	+	task.notifyAll();
1962		}
1856	–	long c; // re-activate
1857	–	do {} while (!U.compareAndSwapLong
1858	–	(this, CTL, c = ctl, c + AC_UNIT));
1963		}
1964	+	long c; // re-activate
1965	+	do {} while (!U.compareAndSwapLong
1966	+	(this, CTL, c = ctl, c + AC_UNIT));
1967		}
1861	–	if (s < 0 \|\| (s = task.status) < 0) {
1862	–	joiner.currentJoin = prevJoin;
1863	–	break;
1864	–	}
1865	–	else if ((k++ & (MAX_HELP - 1)) == MAX_HELP >>> 1)
1866	–	Thread.yield(); // for politeness
1968		}
1969	+	joiner.currentJoin = prevJoin;
1970		}
1971		return s;
1972		}
#	Line 1876 \| Line 1978 \| public class ForkJoinPool extends Abstra
1978		*
1979		* @param joiner the joining worker
1980		* @param task the task
1879	–	* @return task status on exit
1981		*/
1982	<	final int helpJoinOnce(WorkQueue joiner, ForkJoinTask<?> task) {
1982	>	final void helpJoinOnce(WorkQueue joiner, ForkJoinTask<?> task) {
1983		int s;
1984	<	while ((s = task.status) >= 0 &&
1985	<	(joiner.isEmpty() ?
1986	<	tryHelpStealer(joiner, task) :
1987	<	joiner.tryRemoveAndExec(task)) != 0)
1988	<	;
1989	<	return s;
1984	>	if (joiner != null && task != null && (s = task.status) >= 0) {
1985	>	ForkJoinTask<?> prevJoin = joiner.currentJoin;
1986	>	joiner.currentJoin = task;
1987	>	do {} while ((s = task.status) >= 0 &&
1988	>	joiner.queueSize() > 0 &&
1989	>	joiner.tryRemoveAndExec(task));
1990	>	if (s >= 0 && (s = task.status) >= 0 &&
1991	>	(s = helpSignal(task, joiner.poolIndex)) >= 0 &&
1992	>	(task instanceof CountedCompleter))
1993	>	s = helpComplete(task, LIFO_QUEUE);
1994	>	if (s >= 0 && joiner.queueSize() == 0) {
1995	>	do {} while (task.status >= 0 &&
1996	>	tryHelpStealer(joiner, task) > 0);
1997	>	}
1998	>	joiner.currentJoin = prevJoin;
1999	>	}
2000		}
2001
2002		/**
#	Line 1893 \| Line 2004 \| public class ForkJoinPool extends Abstra
2004		* during a random, then cyclic scan, else null. This method must
2005		* be retried by caller if, by the time it tries to use the queue,
2006		* it is empty.
2007	+	* @param r a (random) seed for scanning
2008		*/
2009	<	private WorkQueue findNonEmptyStealQueue(WorkQueue w) {
1898	<	// Similar to loop in scan(), but ignoring submissions
1899	<	int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
2009	>	private WorkQueue findNonEmptyStealQueue(int r) {
2010		int step = (r >>> 16) \| 1;
2011		for (WorkQueue[] ws;;) {
2012	<	int rs = runState, m;
2012	>	int ps = plock, m;
2013		if ((ws = workQueues) == null \|\| (m = ws.length - 1) < 1)
2014		return null;
2015		for (int j = (m + 1) << 2; ; r += step) {
2016		WorkQueue q = ws[((r << 1) \| 1) & m];
2017	<	if (q != null && !q.isEmpty())
2017	>	if (q != null && q.queueSize() > 0)
2018		return q;
2019		else if (--j < 0) {
2020	<	if (runState == rs)
2020	>	if (plock == ps)
2021		return null;
2022		break;
2023		}
#	Line 1915 \| Line 2025 \| public class ForkJoinPool extends Abstra
2025		}
2026		}
2027
1918	–
2028		/**
2029		* Runs tasks until {@code isQuiescent()}. We piggyback on
2030		* active count ctl maintenance, but rather than blocking
#	Line 1927 \| Line 2036 \| public class ForkJoinPool extends Abstra
2036		ForkJoinTask<?> localTask; // exhaust local queue
2037		while ((localTask = w.nextLocalTask()) != null)
2038		localTask.doExec();
2039	<	WorkQueue q = findNonEmptyStealQueue(w);
2039	>	// Similar to loop in scan(), but ignoring submissions
2040	>	WorkQueue q = findNonEmptyStealQueue(w.nextSeed());
2041		if (q != null) {
2042		ForkJoinTask<?> t; int b;
2043		if (!active) { // re-establish active count
#	Line 1967 \| Line 2077 \| public class ForkJoinPool extends Abstra
2077		WorkQueue q; int b;
2078		if ((t = w.nextLocalTask()) != null)
2079		return t;
2080	<	if ((q = findNonEmptyStealQueue(w)) == null)
2080	>	if ((q = findNonEmptyStealQueue(w.nextSeed())) == null)
2081		return null;
2082		if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null)
2083		return t;
#	Line 1975 \| Line 2085 \| public class ForkJoinPool extends Abstra
2085		}
2086
2087		/**
2088	<	* Returns the approximate (non-atomic) number of idle threads per
2089	<	* active thread to offset steal queue size for method
2090	<	* ForkJoinTask.getSurplusQueuedTaskCount().
2091	<	*/
2092	<	final int idlePerActive() {
2093	<	// Approximate at powers of two for small values, saturate past 4
2094	<	int p = parallelism;
2095	<	int a = p + (int)(ctl >> AC_SHIFT);
2096	<	return (a > (p >>>= 1) ? 0 :
2097	<	a > (p >>>= 1) ? 1 :
2098	<	a > (p >>>= 1) ? 2 :
2099	<	a > (p >>>= 1) ? 4 :
2100	<	8);
2088	>	* Returns a cheap heuristic guide for task partitioning when
2089	>	* programmers, frameworks, tools, or languages have little or no
2090	>	* idea about task granularity. In essence by offering this
2091	>	* method, we ask users only about tradeoffs in overhead vs
2092	>	* expected throughput and its variance, rather than how finely to
2093	>	* partition tasks.
2094	>	*
2095	>	* In a steady state strict (tree-structured) computation, each
2096	>	* thread makes available for stealing enough tasks for other
2097	>	* threads to remain active. Inductively, if all threads play by
2098	>	* the same rules, each thread should make available only a
2099	>	* constant number of tasks.
2100	>	*
2101	>	* The minimum useful constant is just 1. But using a value of 1
2102	>	* would require immediate replenishment upon each steal to
2103	>	* maintain enough tasks, which is infeasible. Further,
2104	>	* partitionings/granularities of offered tasks should minimize
2105	>	* steal rates, which in general means that threads nearer the top
2106	>	* of computation tree should generate more than those nearer the
2107	>	* bottom. In perfect steady state, each thread is at
2108	>	* approximately the same level of computation tree. However,
2109	>	* producing extra tasks amortizes the uncertainty of progress and
2110	>	* diffusion assumptions.
2111	>	*
2112	>	* So, users will want to use values larger, but not much larger
2113	>	* than 1 to both smooth over transient shortages and hedge
2114	>	* against uneven progress; as traded off against the cost of
2115	>	* extra task overhead. We leave the user to pick a threshold
2116	>	* value to compare with the results of this call to guide
2117	>	* decisions, but recommend values such as 3.
2118	>	*
2119	>	* When all threads are active, it is on average OK to estimate
2120	>	* surplus strictly locally. In steady-state, if one thread is
2121	>	* maintaining say 2 surplus tasks, then so are others. So we can
2122	>	* just use estimated queue length. However, this strategy alone
2123	>	* leads to serious mis-estimates in some non-steady-state
2124	>	* conditions (ramp-up, ramp-down, other stalls). We can detect
2125	>	* many of these by further considering the number of "idle"
2126	>	* threads, that are known to have zero queued tasks, so
2127	>	* compensate by a factor of (#idle/#active) threads.
2128	>	*
2129	>	* Note: The approximation of #busy workers as #active workers is
2130	>	* not very good under current signalling scheme, and should be
2131	>	* improved.
2132	>	*/
2133	>	static int getSurplusQueuedTaskCount() {
2134	>	Thread t; ForkJoinWorkerThread wt; ForkJoinPool pool; WorkQueue q;
2135	>	if (((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)) {
2136	>	int b = (q = (wt = (ForkJoinWorkerThread)t).workQueue).base;
2137	>	int p = (pool = wt.pool).parallelism;
2138	>	int a = (int)(pool.ctl >> AC_SHIFT) + p;
2139	>	return q.top - b - (a > (p >>>= 1) ? 0 :
2140	>	a > (p >>>= 1) ? 1 :
2141	>	a > (p >>>= 1) ? 2 :
2142	>	a > (p >>>= 1) ? 4 :
2143	>	8);
2144	>	}
2145	>	return 0;
2146		}
2147
2148		// Termination
#	Line 2007 \| Line 2162 \| public class ForkJoinPool extends Abstra
2162		* @return true if now terminating or terminated
2163		*/
2164		private boolean tryTerminate(boolean now, boolean enable) {
2165	<	Mutex lock = this.lock;
2165	>	if (this == commonPool) // cannot shut down
2166	>	return false;
2167		for (long c;;) {
2168		if (((c = ctl) & STOP_BIT) != 0) { // already terminating
2169		if ((short)(c >>> TC_SHIFT) == -parallelism) {
2170	<	lock.lock(); // don't need try/finally
2171	<	termination.signalAll(); // signal when 0 workers
2172	<	lock.unlock();
2170	>	synchronized (this) {
2171	>	notifyAll(); // signal when 0 workers
2172	>	}
2173		}
2174		return true;
2175		}
2176	<	if (runState >= 0) { // not yet enabled
2176	>	if (plock >= 0) { // not yet enabled
2177	>	int ps;
2178		if (!enable)
2179		return false;
2180	<	lock.lock();
2181	<	runState \|= SHUTDOWN;
2182	<	lock.unlock();
2180	>	if (((ps = plock) & PL_LOCK) != 0 \|\|
2181	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
2182	>	ps = acquirePlock();
2183	>	int nps = SHUTDOWN;
2184	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
2185	>	releasePlock(nps);
2186		}
2187		if (!now) { // check if idle & no tasks
2188		if ((int)(c >> AC_SHIFT) != -parallelism \|\|
#	Line 2045 \| Line 2205 \| public class ForkJoinPool extends Abstra
2205		int n = ws.length;
2206		for (int i = 0; i < n; ++i) {
2207		if ((w = ws[i]) != null) {
2208	<	w.runState = -1;
2208	>	w.qlock = -1;
2209		if (pass > 0) {
2210		w.cancelAll();
2211		if (pass > 1)
#	Line 2064 \| Line 2224 \| public class ForkJoinPool extends Abstra
2224		if (w.eventCount == (e \| INT_SIGN) &&
2225		U.compareAndSwapLong(this, CTL, cc, nc)) {
2226		w.eventCount = (e + E_SEQ) & E_MASK;
2227	<	w.runState = -1;
2227	>	w.qlock = -1;
2228		if ((p = w.parker) != null)
2229		U.unpark(p);
2230		}
#	Line 2075 \| Line 2235 \| public class ForkJoinPool extends Abstra
2235		}
2236		}
2237
2238	+	// external operations on common pool
2239	+
2240	+	/**
2241	+	* Returns common pool queue for a thread that has submitted at
2242	+	* least one task.
2243	+	*/
2244	+	static WorkQueue commonSubmitterQueue() {
2245	+	ForkJoinPool p; WorkQueue[] ws; int m; Submitter z;
2246	+	return ((z = submitters.get()) != null &&
2247	+	(p = commonPool) != null &&
2248	+	(ws = p.workQueues) != null &&
2249	+	(m = ws.length - 1) >= 0) ?
2250	+	ws[m & z.seed & SQMASK] : null;
2251	+	}
2252	+
2253	+	/**
2254	+	* Tries to pop the given task from submitter's queue in common pool.
2255	+	*/
2256	+	static boolean tryExternalUnpush(ForkJoinTask<?> t) {
2257	+	ForkJoinPool p; WorkQueue[] ws; WorkQueue q; Submitter z;
2258	+	ForkJoinTask<?>[] a; int m, s; long j;
2259	+	if ((z = submitters.get()) != null &&
2260	+	(p = commonPool) != null &&
2261	+	(ws = p.workQueues) != null &&
2262	+	(m = ws.length - 1) >= 0 &&
2263	+	(q = ws[m & z.seed & SQMASK]) != null &&
2264	+	(s = q.top) != q.base &&
2265	+	(a = q.array) != null &&
2266	+	U.getObjectVolatile
2267	+	(a, j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE) == t &&
2268	+	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2269	+	if (q.array == a && q.top == s && // recheck
2270	+	U.compareAndSwapObject(a, j, t, null)) {
2271	+	q.top = s - 1;
2272	+	q.qlock = 0;
2273	+	return true;
2274	+	}
2275	+	q.qlock = 0;
2276	+	}
2277	+	return false;
2278	+	}
2279	+
2280	+	/**
2281	+	* Tries to pop and run local tasks within the same computation
2282	+	* as the given root. On failure, tries to help complete from
2283	+	* other queues via helpComplete.
2284	+	*/
2285	+	private void externalHelpComplete(WorkQueue q, ForkJoinTask<?> root) {
2286	+	ForkJoinTask<?>[] a; int m;
2287	+	if (q != null && (a = q.array) != null && (m = (a.length - 1)) >= 0 &&
2288	+	root != null && root.status >= 0) {
2289	+	for (;;) {
2290	+	int s; Object o; CountedCompleter<?> task = null;
2291	+	if ((s = q.top) - q.base > 0) {
2292	+	long j = ((m & (s - 1)) << ASHIFT) + ABASE;
2293	+	if ((o = U.getObject(a, j)) != null &&
2294	+	(o instanceof CountedCompleter)) {
2295	+	CountedCompleter<?> t = (CountedCompleter<?>)o, r = t;
2296	+	do {
2297	+	if (r == root) {
2298	+	if (U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2299	+	if (q.array == a && q.top == s &&
2300	+	U.compareAndSwapObject(a, j, t, null)) {
2301	+	q.top = s - 1;
2302	+	task = t;
2303	+	}
2304	+	q.qlock = 0;
2305	+	}
2306	+	break;
2307	+	}
2308	+	} while ((r = r.completer) != null);
2309	+	}
2310	+	}
2311	+	if (task != null)
2312	+	task.doExec();
2313	+	if (root.status < 0 \|\| (int)(ctl >> AC_SHIFT) >= 0)
2314	+	break;
2315	+	if (task == null) {
2316	+	if (helpSignal(root, q.poolIndex) >= 0)
2317	+	helpComplete(root, SHARED_QUEUE);
2318	+	break;
2319	+	}
2320	+	}
2321	+	}
2322	+	}
2323	+
2324	+	/**
2325	+	* Tries to help execute or signal availability of the given task
2326	+	* from submitter's queue in common pool.
2327	+	*/
2328	+	static void externalHelpJoin(ForkJoinTask<?> t) {
2329	+	// Some hard-to-avoid overlap with tryExternalUnpush
2330	+	ForkJoinPool p; WorkQueue[] ws; WorkQueue q, w; Submitter z;
2331	+	ForkJoinTask<?>[] a; int m, s, n; long j;
2332	+	if (t != null && t.status >= 0 &&
2333	+	(z = submitters.get()) != null &&
2334	+	(p = commonPool) != null &&
2335	+	(ws = p.workQueues) != null &&
2336	+	(m = ws.length - 1) >= 0 &&
2337	+	(q = ws[m & z.seed & SQMASK]) != null &&
2338	+	(a = q.array) != null) {
2339	+	if ((s = q.top) != q.base &&
2340	+	U.getObjectVolatile
2341	+	(a, j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE) == t &&
2342	+	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2343	+	if (q.array == a && q.top == s &&
2344	+	U.compareAndSwapObject(a, j, t, null)) {
2345	+	q.top = s - 1;
2346	+	q.qlock = 0;
2347	+	t.doExec();
2348	+	}
2349	+	else
2350	+	q.qlock = 0;
2351	+	}
2352	+	if (t.status >= 0) {
2353	+	if (t instanceof CountedCompleter)
2354	+	p.externalHelpComplete(q, t);
2355	+	else
2356	+	p.helpSignal(t, q.poolIndex);
2357	+	}
2358	+	}
2359	+	}
2360	+
2361	+	/**
2362	+	* Restricted version of helpQuiescePool for external callers
2363	+	*/
2364	+	static void externalHelpQuiescePool() {
2365	+	ForkJoinPool p; ForkJoinTask<?> t; WorkQueue q; int b;
2366	+	int r = ThreadLocalRandom.current().nextInt();
2367	+	if ((p = commonPool) != null &&
2368	+	(q = p.findNonEmptyStealQueue(r)) != null &&
2369	+	(b = q.base) - q.top < 0 &&
2370	+	(t = q.pollAt(b)) != null)
2371	+	t.doExec();
2372	+	}
2373	+
2374		// Exported methods
2375
2376		// Constructors
#	Line 2152 \| Line 2448 \| public class ForkJoinPool extends Abstra
2448		this.localMode = asyncMode ? FIFO_QUEUE : LIFO_QUEUE;
2449		long np = (long)(-parallelism); // offset ctl counts
2450		this.ctl = ((np << AC_SHIFT) & AC_MASK) \| ((np << TC_SHIFT) & TC_MASK);
2451	<	// Use nearest power 2 for workQueues size. See Hackers Delight sec 3.2.
2156	<	int n = parallelism - 1;
2157	<	n \|= n >>> 1; n \|= n >>> 2; n \|= n >>> 4; n \|= n >>> 8; n \|= n >>> 16;
2158	<	int size = (n + 1) << 1; // #slots = 2*#workers
2159	<	this.submitMask = size - 1; // room for max # of submit queues
2160	<	this.workQueues = new WorkQueue[size];
2161	<	this.termination = (this.lock = new Mutex()).newCondition();
2162	<	this.stealCount = new AtomicLong();
2163	<	this.nextWorkerNumber = new AtomicInteger();
2164	<	int pn = poolNumberGenerator.incrementAndGet();
2451	>	int pn = nextPoolId();
2452		StringBuilder sb = new StringBuilder("ForkJoinPool-");
2453		sb.append(Integer.toString(pn));
2454		sb.append("-worker-");
2455		this.workerNamePrefix = sb.toString();
2456	<	lock.lock();
2457	<	this.runState = 1; // set init flag
2458	<	lock.unlock();
2456	>	}
2457	>
2458	>	/**
2459	>	* Constructor for common pool, suitable only for static initialization.
2460	>	* Basically the same as above, but uses smallest possible initial footprint.
2461	>	*/
2462	>	ForkJoinPool(int parallelism, long ctl,
2463	>	ForkJoinWorkerThreadFactory factory,
2464	>	Thread.UncaughtExceptionHandler handler) {
2465	>	this.parallelism = parallelism;
2466	>	this.ctl = ctl;
2467	>	this.factory = factory;
2468	>	this.ueh = handler;
2469	>	this.localMode = LIFO_QUEUE;
2470	>	this.workerNamePrefix = "ForkJoinPool.commonPool-worker-";
2471	>	}
2472	>
2473	>	/**
2474	>	* Returns the common pool instance.
2475	>	*
2476	>	* @return the common pool instance
2477	>	*/
2478	>	public static ForkJoinPool commonPool() {
2479	>	return commonPool; // cannot be null (if so, a static init error)
2480		}
2481
2482		// Execution methods
#	Line 2192 \| Line 2500 \| public class ForkJoinPool extends Abstra
2500		public <T> T invoke(ForkJoinTask<T> task) {
2501		if (task == null)
2502		throw new NullPointerException();
2503	<	doSubmit(task);
2503	>	externalPush(task);
2504		return task.join();
2505		}
2506
#	Line 2207 \| Line 2515 \| public class ForkJoinPool extends Abstra
2515		public void execute(ForkJoinTask<?> task) {
2516		if (task == null)
2517		throw new NullPointerException();
2518	<	doSubmit(task);
2518	>	externalPush(task);
2519		}
2520
2521		// AbstractExecutorService methods
#	Line 2225 \| Line 2533 \| public class ForkJoinPool extends Abstra
2533		job = (ForkJoinTask<?>) task;
2534		else
2535		job = new ForkJoinTask.AdaptedRunnableAction(task);
2536	<	doSubmit(job);
2536	>	externalPush(job);
2537		}
2538
2539		/**
#	Line 2240 \| Line 2548 \| public class ForkJoinPool extends Abstra
2548		public <T> ForkJoinTask<T> submit(ForkJoinTask<T> task) {
2549		if (task == null)
2550		throw new NullPointerException();
2551	<	doSubmit(task);
2551	>	externalPush(task);
2552		return task;
2553		}
2554
#	Line 2251 \| Line 2559 \| public class ForkJoinPool extends Abstra
2559		*/
2560		public <T> ForkJoinTask<T> submit(Callable<T> task) {
2561		ForkJoinTask<T> job = new ForkJoinTask.AdaptedCallable<T>(task);
2562	<	doSubmit(job);
2562	>	externalPush(job);
2563		return job;
2564		}
2565
#	Line 2262 \| Line 2570 \| public class ForkJoinPool extends Abstra
2570		*/
2571		public <T> ForkJoinTask<T> submit(Runnable task, T result) {
2572		ForkJoinTask<T> job = new ForkJoinTask.AdaptedRunnable<T>(task, result);
2573	<	doSubmit(job);
2573	>	externalPush(job);
2574		return job;
2575		}
2576
#	Line 2279 \| Line 2587 \| public class ForkJoinPool extends Abstra
2587		job = (ForkJoinTask<?>) task;
2588		else
2589		job = new ForkJoinTask.AdaptedRunnableAction(task);
2590	<	doSubmit(job);
2590	>	externalPush(job);
2591		return job;
2592		}
2593
#	Line 2301 \| Line 2609 \| public class ForkJoinPool extends Abstra
2609		try {
2610		for (Callable<T> t : tasks) {
2611		ForkJoinTask<T> f = new ForkJoinTask.AdaptedCallable<T>(t);
2612	<	doSubmit(f);
2612	>	externalPush(f);
2613		fs.add(f);
2614		}
2615		for (ForkJoinTask<T> f : fs)
#	Line 2344 \| Line 2652 \| public class ForkJoinPool extends Abstra
2652		}
2653
2654		/**
2655	+	* Returns the targeted parallelism level of the common pool.
2656	+	*
2657	+	* @return the targeted parallelism level of the common pool
2658	+	*/
2659	+	public static int getCommonPoolParallelism() {
2660	+	return commonPoolParallelism;
2661	+	}
2662	+
2663	+	/**
2664		* Returns the number of worker threads that have started but not
2665		* yet terminated. The result returned by this method may differ
2666		* from {@link #getParallelism} when threads are created to
#	Line 2424 \| Line 2741 \| public class ForkJoinPool extends Abstra
2741		* @return the number of steals
2742		*/
2743		public long getStealCount() {
2744	<	long count = stealCount.get();
2744	>	long count = stealCount;
2745		WorkQueue[] ws; WorkQueue w;
2746		if ((ws = workQueues) != null) {
2747		for (int i = 1; i < ws.length; i += 2) {
2748		if ((w = ws[i]) != null)
2749	<	count += w.totalSteals;
2749	>	count += w.nsteals;
2750		}
2751		}
2752		return count;
#	Line 2486 \| Line 2803 \| public class ForkJoinPool extends Abstra
2803		WorkQueue[] ws; WorkQueue w;
2804		if ((ws = workQueues) != null) {
2805		for (int i = 0; i < ws.length; i += 2) {
2806	<	if ((w = ws[i]) != null && !w.isEmpty())
2806	>	if ((w = ws[i]) != null && w.queueSize() != 0)
2807		return true;
2808		}
2809		}
#	Line 2554 \| Line 2871 \| public class ForkJoinPool extends Abstra
2871		public String toString() {
2872		// Use a single pass through workQueues to collect counts
2873		long qt = 0L, qs = 0L; int rc = 0;
2874	<	long st = stealCount.get();
2874	>	long st = stealCount;
2875		long c = ctl;
2876		WorkQueue[] ws; WorkQueue w;
2877		if ((ws = workQueues) != null) {
#	Line 2565 \| Line 2882 \| public class ForkJoinPool extends Abstra
2882		qs += size;
2883		else {
2884		qt += size;
2885	<	st += w.totalSteals;
2885	>	st += w.nsteals;
2886		if (w.isApparentlyUnblocked())
2887		++rc;
2888		}
#	Line 2581 \| Line 2898 \| public class ForkJoinPool extends Abstra
2898		if ((c & STOP_BIT) != 0)
2899		level = (tc == 0) ? "Terminated" : "Terminating";
2900		else
2901	<	level = runState < 0 ? "Shutting down" : "Running";
2901	>	level = plock < 0 ? "Shutting down" : "Running";
2902		return super.toString() +
2903		"[" + level +
2904		", parallelism = " + pc +
#	Line 2595 \| Line 2912 \| public class ForkJoinPool extends Abstra
2912		}
2913
2914		/**
2915	<	* Initiates an orderly shutdown in which previously submitted
2916	<	* tasks are executed, but no new tasks will be accepted.
2917	<	* Invocation has no additional effect if already shut down.
2918	<	* Tasks that are in the process of being submitted concurrently
2919	<	* during the course of this method may or may not be rejected.
2915	>	* Possibly initiates an orderly shutdown in which previously
2916	>	* submitted tasks are executed, but no new tasks will be
2917	>	* accepted. Invocation has no effect on execution state if this
2918	>	* is the {@link #commonPool}, and no additional effect if
2919	>	* already shut down. Tasks that are in the process of being
2920	>	* submitted concurrently during the course of this method may or
2921	>	* may not be rejected.
2922		*
2923		* @throws SecurityException if a security manager exists and
2924		* the caller is not permitted to modify threads
#	Line 2612 \| Line 2931 \| public class ForkJoinPool extends Abstra
2931		}
2932
2933		/**
2934	<	* Attempts to cancel and/or stop all tasks, and reject all
2935	<	* subsequently submitted tasks. Tasks that are in the process of
2936	<	* being submitted or executed concurrently during the course of
2937	<	* this method may or may not be rejected. This method cancels
2938	<	* both existing and unexecuted tasks, in order to permit
2939	<	* termination in the presence of task dependencies. So the method
2940	<	* always returns an empty list (unlike the case for some other
2941	<	* Executors).
2934	>	* Possibly attempts to cancel and/or stop all tasks, and reject
2935	>	* all subsequently submitted tasks. Invocation has no effect on
2936	>	* execution state if this is the {@link #commonPool}, and no
2937	>	* additional effect if already shut down. Otherwise, tasks that
2938	>	* are in the process of being submitted or executed concurrently
2939	>	* during the course of this method may or may not be
2940	>	* rejected. This method cancels both existing and unexecuted
2941	>	* tasks, in order to permit termination in the presence of task
2942	>	* dependencies. So the method always returns an empty list
2943	>	* (unlike the case for some other Executors).
2944		*
2945		* @return an empty list
2946		* @throws SecurityException if a security manager exists and
#	Line 2669 \| Line 2990 \| public class ForkJoinPool extends Abstra
2990		* @return {@code true} if this pool has been shut down
2991		*/
2992		public boolean isShutdown() {
2993	<	return runState < 0;
2993	>	return plock < 0;
2994		}
2995
2996		/**
2997	<	* Blocks until all tasks have completed execution after a shutdown
2998	<	* request, or the timeout occurs, or the current thread is
2999	<	* interrupted, whichever happens first.
2997	>	* Blocks until all tasks have completed execution after a
2998	>	* shutdown request, or the timeout occurs, or the current thread
2999	>	* is interrupted, whichever happens first. Note that the {@link
3000	>	* #commonPool()} never terminates until program shutdown so
3001	>	* this method will always time out.
3002		*
3003		* @param timeout the maximum time to wait
3004		* @param unit the time unit of the timeout argument
#	Line 2686 \| Line 3009 \| public class ForkJoinPool extends Abstra
3009		public boolean awaitTermination(long timeout, TimeUnit unit)
3010		throws InterruptedException {
3011		long nanos = unit.toNanos(timeout);
3012	<	final Mutex lock = this.lock;
3013	<	lock.lock();
3014	<	try {
3015	<	for (;;) {
3016	<	if (isTerminated())
3017	<	return true;
3018	<	if (nanos <= 0)
3019	<	return false;
3020	<	nanos = termination.awaitNanos(nanos);
3012	>	if (isTerminated())
3013	>	return true;
3014	>	long startTime = System.nanoTime();
3015	>	boolean terminated = false;
3016	>	synchronized (this) {
3017	>	for (long waitTime = nanos, millis = 0L;;) {
3018	>	if (terminated = isTerminated() \|\|
3019	>	waitTime <= 0L \|\|
3020	>	(millis = unit.toMillis(waitTime)) <= 0L)
3021	>	break;
3022	>	wait(millis);
3023	>	waitTime = nanos - (System.nanoTime() - startTime);
3024		}
2699	–	} finally {
2700	–	lock.unlock();
3025		}
3026	+	return terminated;
3027		}
3028
3029		/**
#	Line 2797 \| Line 3122 \| public class ForkJoinPool extends Abstra
3122		public static void managedBlock(ManagedBlocker blocker)
3123		throws InterruptedException {
3124		Thread t = Thread.currentThread();
3125	<	ForkJoinPool p = ((t instanceof ForkJoinWorkerThread) ?
3126	<	((ForkJoinWorkerThread)t).pool : null);
3127	<	while (!blocker.isReleasable()) {
3128	<	if (p == null \|\| p.tryCompensate(null, blocker)) {
3129	<	try {
3130	<	do {} while (!blocker.isReleasable() && !blocker.block());
3131	<	} finally {
3132	<	if (p != null)
3125	>	if (t instanceof ForkJoinWorkerThread) {
3126	>	ForkJoinPool p = ((ForkJoinWorkerThread)t).pool;
3127	>	while (!blocker.isReleasable()) { // variant of helpSignal
3128	>	WorkQueue[] ws; WorkQueue q; int m, n;
3129	>	if ((ws = p.workQueues) != null && (m = ws.length - 1) >= 0) {
3130	>	for (int i = 0; i <= m; ++i) {
3131	>	if (blocker.isReleasable())
3132	>	return;
3133	>	if ((q = ws[i]) != null && (n = q.queueSize()) > 0) {
3134	>	p.signalWork(q, n);
3135	>	if ((int)(p.ctl >> AC_SHIFT) >= 0)
3136	>	break;
3137	>	}
3138	>	}
3139	>	}
3140	>	if (p.tryCompensate()) {
3141	>	try {
3142	>	do {} while (!blocker.isReleasable() &&
3143	>	!blocker.block());
3144	>	} finally {
3145		p.incrementActiveCount();
3146	+	}
3147	+	break;
3148		}
2810	–	break;
3149		}
3150		}
3151	+	else {
3152	+	do {} while (!blocker.isReleasable() &&
3153	+	!blocker.block());
3154	+	}
3155		}
3156
3157		// AbstractExecutorService overrides. These rely on undocumented
#	Line 2830 \| Line 3172 \| public class ForkJoinPool extends Abstra
3172		private static final long PARKBLOCKER;
3173		private static final int ABASE;
3174		private static final int ASHIFT;
3175	+	private static final long STEALCOUNT;
3176	+	private static final long PLOCK;
3177	+	private static final long INDEXSEED;
3178	+	private static final long QLOCK;
3179
3180		static {
3181	<	poolNumberGenerator = new AtomicInteger();
3182	<	nextSubmitterSeed = new AtomicInteger(0x55555555);
3183	<	modifyThreadPermission = new RuntimePermission("modifyThread");
3184	<	defaultForkJoinWorkerThreadFactory =
3185	<	new DefaultForkJoinWorkerThreadFactory();
3186	<	submitters = new ThreadSubmitter();
3187	<	int s;
3181	>	// Establish common pool parameters
3182	>	// TBD: limit or report ignored exceptions?
3183	>
3184	>	int par = 0;
3185	>	ForkJoinWorkerThreadFactory fac = null;
3186	>	Thread.UncaughtExceptionHandler handler = null;
3187	>	try {
3188	>	String pp = System.getProperty(propPrefix + "parallelism");
3189	>	String hp = System.getProperty(propPrefix + "exceptionHandler");
3190	>	String fp = System.getProperty(propPrefix + "threadFactory");
3191	>	if (fp != null)
3192	>	fac = ((ForkJoinWorkerThreadFactory)ClassLoader.
3193	>	getSystemClassLoader().loadClass(fp).newInstance());
3194	>	if (hp != null)
3195	>	handler = ((Thread.UncaughtExceptionHandler)ClassLoader.
3196	>	getSystemClassLoader().loadClass(hp).newInstance());
3197	>	if (pp != null)
3198	>	par = Integer.parseInt(pp);
3199	>	} catch (Exception ignore) {
3200	>	}
3201	>
3202	>	int s; // initialize field offsets for CAS etc
3203		try {
3204		U = getUnsafe();
3205		Class<?> k = ForkJoinPool.class;
2845	–	Class<?> ak = ForkJoinTask[].class;
3206		CTL = U.objectFieldOffset
3207		(k.getDeclaredField("ctl"));
3208	+	STEALCOUNT = U.objectFieldOffset
3209	+	(k.getDeclaredField("stealCount"));
3210	+	PLOCK = U.objectFieldOffset
3211	+	(k.getDeclaredField("plock"));
3212	+	INDEXSEED = U.objectFieldOffset
3213	+	(k.getDeclaredField("indexSeed"));
3214		Class<?> tk = Thread.class;
3215		PARKBLOCKER = U.objectFieldOffset
3216		(tk.getDeclaredField("parkBlocker"));
3217	+	Class<?> wk = WorkQueue.class;
3218	+	QLOCK = U.objectFieldOffset
3219	+	(wk.getDeclaredField("qlock"));
3220	+	Class<?> ak = ForkJoinTask[].class;
3221		ABASE = U.arrayBaseOffset(ak);
3222		s = U.arrayIndexScale(ak);
3223	+	ASHIFT = 31 - Integer.numberOfLeadingZeros(s);
3224		} catch (Exception e) {
3225		throw new Error(e);
3226		}
3227		if ((s & (s-1)) != 0)
3228		throw new Error("data type scale not a power of two");
3229	<	ASHIFT = 31 - Integer.numberOfLeadingZeros(s);
3229	>
3230	>	/*
3231	>	* For extra caution, computations to set up pool state are
3232	>	* here; the constructor just assigns these values to fields.
3233	>	*/
3234	>	ForkJoinWorkerThreadFactory defaultFac =
3235	>	defaultForkJoinWorkerThreadFactory =
3236	>	new DefaultForkJoinWorkerThreadFactory();
3237	>	if (fac == null)
3238	>	fac = defaultFac;
3239	>	if (par <= 0)
3240	>	par = Runtime.getRuntime().availableProcessors();
3241	>	if (par > MAX_CAP)
3242	>	par = MAX_CAP;
3243	>	long np = (long)(-par); // precompute initial ctl value
3244	>	long ct = ((np << AC_SHIFT) & AC_MASK) \| ((np << TC_SHIFT) & TC_MASK);
3245	>
3246	>	commonPoolParallelism = par;
3247	>	commonPool = new ForkJoinPool(par, ct, fac, handler);
3248	>	modifyThreadPermission = new RuntimePermission("modifyThread");
3249	>	submitters = new ThreadLocal<Submitter>();
3250		}
3251
3252		/**

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Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents): Revision 1.132 by jsr166, Fri Oct 12 16:46:37 2012 UTC vs. Revision 1.145 by jsr166, Mon Nov 19 01:04:24 2012 UTC

Diff Legend

Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.132 by jsr166, Fri Oct 12 16:46:37 2012 UTC vs.
Revision 1.145 by jsr166, Mon Nov 19 01:04:24 2012 UTC