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root/jsr166/jsr166/src/jsr166y/ForkJoinPool.java

Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.16 by jsr166, Thu Jul 23 19:44:46 2009 UTC vs.
Revision 1.21 by jsr166, Fri Jul 24 23:47:01 2009 UTC

#	Line 9 | Line 9 | import java.util.*;
9		import java.util.concurrent.*;
10		import java.util.concurrent.locks.*;
11		import java.util.concurrent.atomic.*;
12	–	import sun.misc.Unsafe;
13	–	import java.lang.reflect.*;
12
13		/**
14		* An {@link ExecutorService} for running {@link ForkJoinTask}s.  A
#	Line 90 | Line 88 | public class ForkJoinPool extends Abstra
88		}
89
90		/**
91	<	* Default ForkJoinWorkerThreadFactory implementation, creates a
91	>	* Default ForkJoinWorkerThreadFactory implementation; creates a
92		* new ForkJoinWorkerThread.
93		*/
94		static class  DefaultForkJoinWorkerThreadFactory
#	Line 184 | Line 182 | public class ForkJoinPool extends Abstra
182		private final LinkedTransferQueue<ForkJoinTask<?>> submissionQueue;
183
184		/**
185	<	* Head of Treiber stack for barrier sync. See below for explanation
185	>	* Head of Treiber stack for barrier sync. See below for explanation.
186		*/
187		private volatile WaitQueueNode syncStack;
188
#	Line 232 | Line 230 | public class ForkJoinPool extends Abstra
230		* Adds delta (which may be negative) to running count.  This must
231		* be called before (with negative arg) and after (with positive)
232		* any managed synchronization (i.e., mainly, joins).
233	+	*
234		* @param delta the number to add
235		*/
236		final void updateRunningCount(int delta) {
237		int s;
238	<	do;while (!casWorkerCounts(s = workerCounts, s + delta));
238	>	do {} while (!casWorkerCounts(s = workerCounts, s + delta));
239		}
240
241		/**
242		* Adds delta (which may be negative) to both total and running
243		* count.  This must be called upon creation and termination of
244		* worker threads.
245	+	*
246		* @param delta the number to add
247		*/
248		private void updateWorkerCount(int delta) {
249		int d = delta + (delta << 16); // add to both lo and hi parts
250		int s;
251	<	do;while (!casWorkerCounts(s = workerCounts, s + d));
251	>	do {} while (!casWorkerCounts(s = workerCounts, s + d));
252		}
253
254		/**
#	Line 274 | Line 274 | public class ForkJoinPool extends Abstra
274		private static int runControlFor(int r, int a)   { return (r << 16) + a; }
275
276		/**
277	<	* Try incrementing active count; fail on contention. Called by
278	<	* workers before/during executing tasks.
277	>	* Tries incrementing active count; fails on contention.
278	>	* Called by workers before/during executing tasks.
279	>	*
280		* @return true on success
281		*/
282		final boolean tryIncrementActiveCount() {
#	Line 287 | Line 288 | public class ForkJoinPool extends Abstra
288		* Tries decrementing active count; fails on contention.
289		* Possibly triggers termination on success.
290		* Called by workers when they can't find tasks.
291	+	*
292		* @return true on success
293		*/
294		final boolean tryDecrementActiveCount() {
#	Line 305 | Line 307 | public class ForkJoinPool extends Abstra
307		* terminating on shutdown.
308		*/
309		private static boolean canTerminateOnShutdown(int c) {
310	<	return ((c & -c) >>> 16) != 0; // i.e. least bit is nonzero runState bit
310	>	// i.e. least bit is nonzero runState bit
311	>	return ((c & -c) >>> 16) != 0;
312		}
313
314		/**
#	Line 331 | Line 334 | public class ForkJoinPool extends Abstra
334
335		/**
336		* Creates a ForkJoinPool with a pool size equal to the number of
337	<	* processors available on the system and using the default
338	<	* ForkJoinWorkerThreadFactory,
337	>	* processors available on the system, using the default
338	>	* ForkJoinWorkerThreadFactory.
339	>	*
340		* @throws SecurityException if a security manager exists and
341		*         the caller is not permitted to modify threads
342		*         because it does not hold {@link
343	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
343	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
344		*/
345		public ForkJoinPool() {
346		this(Runtime.getRuntime().availableProcessors(),
#	Line 345 | Line 349 | public class ForkJoinPool extends Abstra
349
350		/**
351		* Creates a ForkJoinPool with the indicated parallelism level
352	<	* threads, and using the default ForkJoinWorkerThreadFactory,
352	>	* threads and using the default ForkJoinWorkerThreadFactory.
353	>	*
354		* @param parallelism the number of worker threads
355		* @throws IllegalArgumentException if parallelism less than or
356		* equal to zero
357		* @throws SecurityException if a security manager exists and
358		*         the caller is not permitted to modify threads
359		*         because it does not hold {@link
360	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
360	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
361		*/
362		public ForkJoinPool(int parallelism) {
363		this(parallelism, defaultForkJoinWorkerThreadFactory);
#	Line 361 | Line 366 | public class ForkJoinPool extends Abstra
366		/**
367		* Creates a ForkJoinPool with parallelism equal to the number of
368		* processors available on the system and using the given
369	<	* ForkJoinWorkerThreadFactory,
369	>	* ForkJoinWorkerThreadFactory.
370	>	*
371		* @param factory the factory for creating new threads
372		* @throws NullPointerException if factory is null
373		* @throws SecurityException if a security manager exists and
374		*         the caller is not permitted to modify threads
375		*         because it does not hold {@link
376	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
376	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
377		*/
378		public ForkJoinPool(ForkJoinWorkerThreadFactory factory) {
379		this(Runtime.getRuntime().availableProcessors(), factory);
#	Line 384 | Line 390 | public class ForkJoinPool extends Abstra
390		* @throws SecurityException if a security manager exists and
391		*         the caller is not permitted to modify threads
392		*         because it does not hold {@link
393	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
393	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
394		*/
395		public ForkJoinPool(int parallelism, ForkJoinWorkerThreadFactory factory) {
396		if (parallelism <= 0 || parallelism > MAX_THREADS)
#	Line 405 | Line 411 | public class ForkJoinPool extends Abstra
411		}
412
413		/**
414	<	* Create new worker using factory.
414	>	* Creates a new worker thread using factory.
415	>	*
416		* @param index the index to assign worker
417		* @return new worker, or null of factory failed
418		*/
#	Line 427 | Line 434 | public class ForkJoinPool extends Abstra
434		* Returns a good size for worker array given pool size.
435		* Currently requires size to be a power of two.
436		*/
437	<	private static int arraySizeFor(int ps) {
438	<	return ps <= 1? 1 : (1 << (32 - Integer.numberOfLeadingZeros(ps-1)));
437	>	private static int arraySizeFor(int poolSize) {
438	>	return (poolSize <= 1) ? 1 :
439	>	(1 << (32 - Integer.numberOfLeadingZeros(poolSize-1)));
440		}
441
442		/**
#	Line 448 | Line 456 | public class ForkJoinPool extends Abstra
456		}
457
458		/**
459	<	* Try to shrink workers into smaller array after one or more terminate
459	>	* Tries to shrink workers into smaller array after one or more terminate.
460		*/
461		private void tryShrinkWorkerArray() {
462		ForkJoinWorkerThread[] ws = workers;
#	Line 464 | Line 472 | public class ForkJoinPool extends Abstra
472		}
473
474		/**
475	<	* Initialize workers if necessary
475	>	* Initializes workers if necessary.
476		*/
477		final void ensureWorkerInitialization() {
478		ForkJoinWorkerThread[] ws = workers;
#	Line 540 | Line 548 | public class ForkJoinPool extends Abstra
548		}
549
550		/**
551	<	* Performs the given task; returning its result upon completion
551	>	* Performs the given task, returning its result upon completion.
552	>	*
553		* @param task the task
554		* @return the task's result
555		* @throws NullPointerException if task is null
#	Line 553 | Line 562 | public class ForkJoinPool extends Abstra
562
563		/**
564		* Arranges for (asynchronous) execution of the given task.
565	+	*
566		* @param task the task
567		* @throws NullPointerException if task is null
568		* @throws RejectedExecutionException if pool is shut down
#	Line 587 | Line 597 | public class ForkJoinPool extends Abstra
597
598		/**
599		* Adaptor for Runnables. This implements RunnableFuture
600	<	* to be compliant with AbstractExecutorService constraints
600	>	* to be compliant with AbstractExecutorService constraints.
601		*/
602		static final class AdaptedRunnable<T> extends ForkJoinTask<T>
603		implements RunnableFuture<T> {
#	Line 607 | Line 617 | public class ForkJoinPool extends Abstra
617		return true;
618		}
619		public void run() { invoke(); }
620	+	private static final long serialVersionUID = 5232453952276885070L;
621		}
622
623		/**
#	Line 635 | Line 646 | public class ForkJoinPool extends Abstra
646		}
647		}
648		public void run() { invoke(); }
649	+	private static final long serialVersionUID = 2838392045355241008L;
650		}
651
652		public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) {
653	<	ArrayList<ForkJoinTask<T>> ts =
653	>	ArrayList<ForkJoinTask<T>> forkJoinTasks =
654		new ArrayList<ForkJoinTask<T>>(tasks.size());
655	<	for (Callable<T> c : tasks)
656	<	ts.add(new AdaptedCallable<T>(c));
657	<	invoke(new InvokeAll<T>(ts));
658	<	return (List<Future<T>>)(List)ts;
655	>	for (Callable<T> task : tasks)
656	>	forkJoinTasks.add(new AdaptedCallable<T>(task));
657	>	invoke(new InvokeAll<T>(forkJoinTasks));
658	>
659	>	@SuppressWarnings({"unchecked", "rawtypes"})
660	>	List<Future<T>> futures = (List<Future<T>>) (List) forkJoinTasks;
661	>	return futures;
662		}
663
664		static final class InvokeAll<T> extends RecursiveAction {
665		final ArrayList<ForkJoinTask<T>> tasks;
666		InvokeAll(ArrayList<ForkJoinTask<T>> tasks) { this.tasks = tasks; }
667		public void compute() {
668	<	try { invokeAll(tasks); } catch(Exception ignore) {}
668	>	try { invokeAll(tasks); }
669	>	catch (Exception ignore) {}
670		}
671	+	private static final long serialVersionUID = -7914297376763021607L;
672		}
673
674		// Configuration and status settings and queries
675
676		/**
677	<	* Returns the factory used for constructing new workers
677	>	* Returns the factory used for constructing new workers.
678		*
679		* @return the factory used for constructing new workers
680		*/
#	Line 668 | Line 685 | public class ForkJoinPool extends Abstra
685		/**
686		* Returns the handler for internal worker threads that terminate
687		* due to unrecoverable errors encountered while executing tasks.
688	+	*
689		* @return the handler, or null if none
690		*/
691		public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() {
#	Line 693 | Line 711 | public class ForkJoinPool extends Abstra
711		* @throws SecurityException if a security manager exists and
712		*         the caller is not permitted to modify threads
713		*         because it does not hold {@link
714	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
714	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
715		*/
716		public Thread.UncaughtExceptionHandler
717		setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler h) {
#	Line 721 | Line 739 | public class ForkJoinPool extends Abstra
739
740		/**
741		* Sets the target parallelism level of this pool.
742	+	*
743		* @param parallelism the target parallelism
744		* @throws IllegalArgumentException if parallelism less than or
745		* equal to zero or greater than maximum size bounds
746		* @throws SecurityException if a security manager exists and
747		*         the caller is not permitted to modify threads
748		*         because it does not hold {@link
749	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
749	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
750		*/
751		public void setParallelism(int parallelism) {
752		checkPermission();
#	Line 774 | Line 793 | public class ForkJoinPool extends Abstra
793		/**
794		* Returns the maximum number of threads allowed to exist in the
795		* pool, even if there are insufficient unblocked running threads.
796	+	*
797		* @return the maximum
798		*/
799		public int getMaximumPoolSize() {
#	Line 785 | Line 805 | public class ForkJoinPool extends Abstra
805		* pool, even if there are insufficient unblocked running threads.
806		* Setting this value has no effect on current pool size. It
807		* controls construction of new threads.
808	+	*
809		* @throws IllegalArgumentException if negative or greater then
810		* internal implementation limit
811		*/
#	Line 799 | Line 820 | public class ForkJoinPool extends Abstra
820		* Returns true if this pool dynamically maintains its target
821		* parallelism level. If false, new threads are added only to
822		* avoid possible starvation.
823	<	* This setting is by default true;
823	>	* This setting is by default true.
824	>	*
825		* @return true if maintains parallelism
826		*/
827		public boolean getMaintainsParallelism() {
#	Line 810 | Line 832 | public class ForkJoinPool extends Abstra
832		* Sets whether this pool dynamically maintains its target
833		* parallelism level. If false, new threads are added only to
834		* avoid possible starvation.
835	+	*
836		* @param enable true to maintains parallelism
837		*/
838		public void setMaintainsParallelism(boolean enable) {
#	Line 867 | Line 890 | public class ForkJoinPool extends Abstra
890		* Returns an estimate of the number of threads that are currently
891		* stealing or executing tasks. This method may overestimate the
892		* number of active threads.
893	+	*
894		* @return the number of active threads
895		*/
896		public int getActiveThreadCount() {
#	Line 877 | Line 901 | public class ForkJoinPool extends Abstra
901		* Returns an estimate of the number of threads that are currently
902		* idle waiting for tasks. This method may underestimate the
903		* number of idle threads.
904	+	*
905		* @return the number of idle threads
906		*/
907		final int getIdleThreadCount() {
908		int c = runningCountOf(workerCounts) - activeCountOf(runControl);
909	<	return (c <= 0)? 0 : c;
909	>	return (c <= 0) ? 0 : c;
910		}
911
912		/**
913		* Returns true if all worker threads are currently idle. An idle
914		* worker is one that cannot obtain a task to execute because none
915		* are available to steal from other threads, and there are no
916	<	* pending submissions to the pool. This method is conservative:
917	<	* It might not return true immediately upon idleness of all
916	>	* pending submissions to the pool. This method is conservative;
917	>	* it might not return true immediately upon idleness of all
918		* threads, but will eventually become true if threads remain
919		* inactive.
920	+	*
921		* @return true if all threads are currently idle
922		*/
923		public boolean isQuiescent() {
#	Line 903 | Line 929 | public class ForkJoinPool extends Abstra
929		* one thread's work queue by another. The reported value
930		* underestimates the actual total number of steals when the pool
931		* is not quiescent. This value may be useful for monitoring and
932	<	* tuning fork/join programs: In general, steal counts should be
932	>	* tuning fork/join programs: in general, steal counts should be
933		* high enough to keep threads busy, but low enough to avoid
934		* overhead and contention across threads.
935	+	*
936		* @return the number of steals
937		*/
938		public long getStealCount() {
#	Line 913 | Line 940 | public class ForkJoinPool extends Abstra
940		}
941
942		/**
943	<	* Accumulate steal count from a worker. Call only
944	<	* when worker known to be idle.
943	>	* Accumulates steal count from a worker.
944	>	* Call only when worker known to be idle.
945		*/
946		private void updateStealCount(ForkJoinWorkerThread w) {
947		int sc = w.getAndClearStealCount();
#	Line 929 | Line 956 | public class ForkJoinPool extends Abstra
956		* an approximation, obtained by iterating across all threads in
957		* the pool. This method may be useful for tuning task
958		* granularities.
959	+	*
960		* @return the number of queued tasks
961		*/
962		public long getQueuedTaskCount() {
#	Line 948 | Line 976 | public class ForkJoinPool extends Abstra
976		* Returns an estimate of the number tasks submitted to this pool
977		* that have not yet begun executing. This method takes time
978		* proportional to the number of submissions.
979	+	*
980		* @return the number of queued submissions
981		*/
982		public int getQueuedSubmissionCount() {
#	Line 957 | Line 986 | public class ForkJoinPool extends Abstra
986		/**
987		* Returns true if there are any tasks submitted to this pool
988		* that have not yet begun executing.
989	+	*
990		* @return {@code true} if there are any queued submissions
991		*/
992		public boolean hasQueuedSubmissions() {
#	Line 967 | Line 997 | public class ForkJoinPool extends Abstra
997		* Removes and returns the next unexecuted submission if one is
998		* available.  This method may be useful in extensions to this
999		* class that re-assign work in systems with multiple pools.
1000	+	*
1001		* @return the next submission, or null if none
1002		*/
1003		protected ForkJoinTask<?> pollSubmission() {
#	Line 986 | Line 1017 | public class ForkJoinPool extends Abstra
1017		* exception is thrown.  The behavior of this operation is
1018		* undefined if the specified collection is modified while the
1019		* operation is in progress.
1020	+	*
1021		* @param c the collection to transfer elements into
1022		* @return the number of elements transferred
1023		*/
#	Line 1046 | Line 1078 | public class ForkJoinPool extends Abstra
1078		* Invocation has no additional effect if already shut down.
1079		* Tasks that are in the process of being submitted concurrently
1080		* during the course of this method may or may not be rejected.
1081	+	*
1082		* @throws SecurityException if a security manager exists and
1083		*         the caller is not permitted to modify threads
1084		*         because it does not hold {@link
1085	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
1085	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
1086		*/
1087		public void shutdown() {
1088		checkPermission();
#	Line 1067 | Line 1100 | public class ForkJoinPool extends Abstra
1100		* upon termination, so always returns an empty list. However, you
1101		* can use method {@code drainTasksTo} before invoking this
1102		* method to transfer unexecuted tasks to another collection.
1103	+	*
1104		* @return an empty list
1105		* @throws SecurityException if a security manager exists and
1106		*         the caller is not permitted to modify threads
1107		*         because it does not hold {@link
1108	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
1108	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
1109		*/
1110		public List<Runnable> shutdownNow() {
1111		checkPermission();
#	Line 1139 | Line 1173 | public class ForkJoinPool extends Abstra
1173		// Shutdown and termination support
1174
1175		/**
1176	<	* Callback from terminating worker. Null out the corresponding
1177	<	* workers slot, and if terminating, try to terminate, else try to
1178	<	* shrink workers array.
1176	>	* Callback from terminating worker. Nulls out the corresponding
1177	>	* workers slot, and if terminating, tries to terminate; else
1178	>	* tries to shrink workers array.
1179	>	*
1180		* @param w the worker
1181		*/
1182		final void workerTerminated(ForkJoinWorkerThread w) {
#	Line 1172 | Line 1207 | public class ForkJoinPool extends Abstra
1207		}
1208
1209		/**
1210	<	* Initiate termination.
1210	>	* Initiates termination.
1211		*/
1212		private void terminate() {
1213		if (transitionRunStateTo(TERMINATING)) {
#	Line 1349 | Line 1384 | public class ForkJoinPool extends Abstra
1384		* Ensures that no thread is waiting for count to advance from the
1385		* current value of eventCount read on entry to this method, by
1386		* releasing waiting threads if necessary.
1387	+	*
1388		* @return the count
1389		*/
1390		final long ensureSync() {
#	Line 1370 | Line 1406 | public class ForkJoinPool extends Abstra
1406		*/
1407		private void signalIdleWorkers() {
1408		long c;
1409	<	do;while (!casEventCount(c = eventCount, c+1));
1409	>	do {} while (!casEventCount(c = eventCount, c+1));
1410		ensureSync();
1411		}
1412
#	Line 1394 | Line 1430 | public class ForkJoinPool extends Abstra
1430		* Waits until event count advances from last value held by
1431		* caller, or if excess threads, caller is resumed as spare, or
1432		* caller or pool is terminating. Updates caller's event on exit.
1433	+	*
1434		* @param w the calling worker thread
1435		*/
1436		final void sync(ForkJoinWorkerThread w) {
#	Line 1424 | Line 1461 | public class ForkJoinPool extends Abstra
1461		* Returns true if worker waiting on sync can proceed:
1462		*  - on signal (thread == null)
1463		*  - on event count advance (winning race to notify vs signaller)
1464	<	*  - on Interrupt
1464	>	*  - on interrupt
1465		*  - if the first queued node, we find work available
1466		* If node was not signalled and event count not advanced on exit,
1467		* then we also help advance event count.
1468	+	*
1469		* @return true if node can be released
1470		*/
1471		final boolean syncIsReleasable(WaitQueueNode node) {
#	Line 1468 | Line 1506 | public class ForkJoinPool extends Abstra
1506		* spare thread when one is about to block (and remove or
1507		* suspend it later when unblocked -- see suspendIfSpare).
1508		* However, implementing this idea requires coping with
1509	<	* several problems: We have imperfect information about the
1509	>	* several problems: we have imperfect information about the
1510		* states of threads. Some count updates can and usually do
1511		* lag run state changes, despite arrangements to keep them
1512		* accurate (for example, when possible, updating counts
#	Line 1491 | Line 1529 | public class ForkJoinPool extends Abstra
1529		* target counts, else create only to avoid starvation
1530		* @return true if joinMe known to be done
1531		*/
1532	<	final boolean preJoin(ForkJoinTask<?> joinMe, boolean maintainParallelism) {
1532	>	final boolean preJoin(ForkJoinTask<?> joinMe,
1533	>	boolean maintainParallelism) {
1534		maintainParallelism &= maintainsParallelism; // overrride
1535		boolean dec = false;  // true when running count decremented
1536		while (spareStack == null || !tryResumeSpare(dec)) {
1537		int counts = workerCounts;
1538	<	if (dec || (dec = casWorkerCounts(counts, --counts))) { // CAS cheat
1538	>	if (dec || (dec = casWorkerCounts(counts, --counts))) {
1539	>	// CAS cheat
1540		if (!needSpare(counts, maintainParallelism))
1541		break;
1542		if (joinMe.status < 0)
#	Line 1511 | Line 1551 | public class ForkJoinPool extends Abstra
1551		/**
1552		* Same idea as preJoin
1553		*/
1554	<	final boolean preBlock(ManagedBlocker blocker, boolean maintainParallelism){
1554	>	final boolean preBlock(ManagedBlocker blocker,
1555	>	boolean maintainParallelism) {
1556		maintainParallelism &= maintainsParallelism;
1557		boolean dec = false;
1558		while (spareStack == null || !tryResumeSpare(dec)) {
#	Line 1535 | Line 1576 | public class ForkJoinPool extends Abstra
1576		* there is apparently some work to do.  This self-limiting rule
1577		* means that the more threads that have already been added, the
1578		* less parallelism we will tolerate before adding another.
1579	+	*
1580		* @param counts current worker counts
1581		* @param maintainParallelism try to maintain parallelism
1582		*/
#	Line 1554 | Line 1596 | public class ForkJoinPool extends Abstra
1596		/**
1597		* Adds a spare worker if lock available and no more than the
1598		* expected numbers of threads exist.
1599	+	*
1600		* @return true if successful
1601		*/
1602		private boolean tryAddSpare(int expectedCounts) {
#	Line 1613 | Line 1656 | public class ForkJoinPool extends Abstra
1656		* the same WaitQueueNodes as barriers.  They are resumed mainly
1657		* in preJoin, but are also woken on pool events that require all
1658		* threads to check run state.
1659	+	*
1660		* @param w the caller
1661		*/
1662		private boolean suspendIfSpare(ForkJoinWorkerThread w) {
#	Line 1623 | Line 1667 | public class ForkJoinPool extends Abstra
1667		node = new WaitQueueNode(0, w);
1668		if (casWorkerCounts(s, s-1)) { // representation-dependent
1669		// push onto stack
1670	<	do;while (!casSpareStack(node.next = spareStack, node));
1670	>	do {} while (!casSpareStack(node.next = spareStack, node));
1671		// block until released by resumeSpare
1672		node.awaitSpareRelease();
1673		return true;
#	Line 1634 | Line 1678 | public class ForkJoinPool extends Abstra
1678
1679		/**
1680		* Tries to pop and resume a spare thread.
1681	+	*
1682		* @param updateCount if true, increment running count on success
1683		* @return true if successful
1684		*/
#	Line 1652 | Line 1697 | public class ForkJoinPool extends Abstra
1697
1698		/**
1699		* Pops and resumes all spare threads. Same idea as ensureSync.
1700	+	*
1701		* @return true if any spares released
1702		*/
1703		private boolean resumeAllSpares() {
#	Line 1695 | Line 1741 | public class ForkJoinPool extends Abstra
1741		* Interface for extending managed parallelism for tasks running
1742		* in ForkJoinPools. A ManagedBlocker provides two methods.
1743		* Method {@code isReleasable} must return true if blocking is not
1744	<	* necessary. Method {@code block} blocks the current thread
1745	<	* if necessary (perhaps internally invoking isReleasable before
1746	<	* actually blocking.).
1744	>	* necessary. Method {@code block} blocks the current thread if
1745	>	* necessary (perhaps internally invoking {@code isReleasable}
1746	>	* before actually blocking.).
1747	>	*
1748		* <p>For example, here is a ManagedBlocker based on a
1749		* ReentrantLock:
1750	<	* <pre>
1751	<	*   class ManagedLocker implements ManagedBlocker {
1752	<	*     final ReentrantLock lock;
1753	<	*     boolean hasLock = false;
1754	<	*     ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1755	<	*     public boolean block() {
1756	<	*        if (!hasLock)
1757	<	*           lock.lock();
1758	<	*        return true;
1759	<	*     }
1760	<	*     public boolean isReleasable() {
1761	<	*        return hasLock || (hasLock = lock.tryLock());
1715	<	*     }
1750	>	*  <pre> {@code
1751	>	* class ManagedLocker implements ManagedBlocker {
1752	>	*   final ReentrantLock lock;
1753	>	*   boolean hasLock = false;
1754	>	*   ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1755	>	*   public boolean block() {
1756	>	*     if (!hasLock)
1757	>	*       lock.lock();
1758	>	*     return true;
1759	>	*   }
1760	>	*   public boolean isReleasable() {
1761	>	*     return hasLock || (hasLock = lock.tryLock());
1762		*   }
1763	<	* </pre>
1763	>	* }}</pre>
1764		*/
1765		public static interface ManagedBlocker {
1766		/**
1767		* Possibly blocks the current thread, for example waiting for
1768		* a lock or condition.
1769	+	*
1770		* @return true if no additional blocking is necessary (i.e.,
1771		* if isReleasable would return true)
1772		* @throws InterruptedException if interrupted while waiting
1773	<	* (the method is not required to do so, but is allowed to).
1773	>	* (the method is not required to do so, but is allowed to)
1774		*/
1775		boolean block() throws InterruptedException;
1776
#	Line 1740 | Line 1787 | public class ForkJoinPool extends Abstra
1787		* while the current thread is blocked.  If
1788		* {@code maintainParallelism} is true and the pool supports
1789		* it ({@link #getMaintainsParallelism}), this method attempts to
1790	<	* maintain the pool's nominal parallelism. Otherwise if activates
1790	>	* maintain the pool's nominal parallelism. Otherwise it activates
1791		* a thread only if necessary to avoid complete starvation. This
1792		* option may be preferable when blockages use timeouts, or are
1793		* almost always brief.
1794		*
1795		* <p> If the caller is not a ForkJoinTask, this method is behaviorally
1796		* equivalent to
1797	<	* <pre>
1798	<	*   while (!blocker.isReleasable())
1799	<	*      if (blocker.block())
1800	<	*         return;
1801	<	* </pre>
1797	>	*  <pre> {@code
1798	>	* while (!blocker.isReleasable())
1799	>	*   if (blocker.block())
1800	>	*     return;
1801	>	* }</pre>
1802		* If the caller is a ForkJoinTask, then the pool may first
1803		* be expanded to ensure parallelism, and later adjusted.
1804		*
#	Line 1766 | Line 1813 | public class ForkJoinPool extends Abstra
1813		boolean maintainParallelism)
1814		throws InterruptedException {
1815		Thread t = Thread.currentThread();
1816	<	ForkJoinPool pool = (t instanceof ForkJoinWorkerThread?
1817	<	((ForkJoinWorkerThread)t).pool : null);
1816	>	ForkJoinPool pool = ((t instanceof ForkJoinWorkerThread) ?
1817	>	((ForkJoinWorkerThread) t).pool : null);
1818		if (!blocker.isReleasable()) {
1819		try {
1820		if (pool == null ||
#	Line 1782 | Line 1829 | public class ForkJoinPool extends Abstra
1829
1830		private static void awaitBlocker(ManagedBlocker blocker)
1831		throws InterruptedException {
1832	<	do;while (!blocker.isReleasable() && !blocker.block());
1832	>	do {} while (!blocker.isReleasable() && !blocker.block());
1833		}
1834
1835		// AbstractExecutorService overrides
1836
1837		protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) {
1838	<	return new AdaptedRunnable(runnable, value);
1838	>	return new AdaptedRunnable<T>(runnable, value);
1839		}
1840
1841		protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
1842	<	return new AdaptedCallable(callable);
1842	>	return new AdaptedCallable<T>(callable);
1843		}
1844
1845
1846	<	// Temporary Unsafe mechanics for preliminary release
1847	<	private static Unsafe getUnsafe() throws Throwable {
1846	>	// Unsafe mechanics for jsr166y 3rd party package.
1847	>	private static sun.misc.Unsafe getUnsafe() {
1848		try {
1849	<	return Unsafe.getUnsafe();
1849	>	return sun.misc.Unsafe.getUnsafe();
1850		} catch (SecurityException se) {
1851		try {
1852		return java.security.AccessController.doPrivileged
1853	<	(new java.security.PrivilegedExceptionAction<Unsafe>() {
1854	<	public Unsafe run() throws Exception {
1855	<	return getUnsafePrivileged();
1853	>	(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
1854	>	public sun.misc.Unsafe run() throws Exception {
1855	>	return getUnsafeByReflection();
1856		}});
1857		} catch (java.security.PrivilegedActionException e) {
1858	<	throw e.getCause();
1858	>	throw new RuntimeException("Could not initialize intrinsics",
1859	>	e.getCause());
1860		}
1861		}
1862		}
1863
1864	<	private static Unsafe getUnsafePrivileged()
1864	>	private static sun.misc.Unsafe getUnsafeByReflection()
1865		throws NoSuchFieldException, IllegalAccessException {
1866	<	Field f = Unsafe.class.getDeclaredField("theUnsafe");
1866	>	java.lang.reflect.Field f =
1867	>	sun.misc.Unsafe.class.getDeclaredField("theUnsafe");
1868		f.setAccessible(true);
1869	<	return (Unsafe) f.get(null);
1821	<	}
1822	<
1823	<	private static long fieldOffset(String fieldName)
1824	<	throws NoSuchFieldException {
1825	<	return UNSAFE.objectFieldOffset
1826	<	(ForkJoinPool.class.getDeclaredField(fieldName));
1869	>	return (sun.misc.Unsafe) f.get(null);
1870		}
1871
1872	<	static final Unsafe UNSAFE;
1830	<	static final long eventCountOffset;
1831	<	static final long workerCountsOffset;
1832	<	static final long runControlOffset;
1833	<	static final long syncStackOffset;
1834	<	static final long spareStackOffset;
1835	<
1836	<	static {
1872	>	private static long fieldOffset(String fieldName, Class<?> klazz) {
1873		try {
1874	<	UNSAFE = getUnsafe();
1875	<	eventCountOffset = fieldOffset("eventCount");
1876	<	workerCountsOffset = fieldOffset("workerCounts");
1877	<	runControlOffset = fieldOffset("runControl");
1878	<	syncStackOffset = fieldOffset("syncStack");
1879	<	spareStackOffset = fieldOffset("spareStack");
1844	<	} catch (Throwable e) {
1845	<	throw new RuntimeException("Could not initialize intrinsics", e);
1874	>	return UNSAFE.objectFieldOffset(klazz.getDeclaredField(fieldName));
1875	>	} catch (NoSuchFieldException e) {
1876	>	// Convert Exception to Error
1877	>	NoSuchFieldError error = new NoSuchFieldError(fieldName);
1878	>	error.initCause(e);
1879	>	throw error;
1880		}
1881		}
1882
1883	+	private static final sun.misc.Unsafe UNSAFE = getUnsafe();
1884	+	static final long eventCountOffset =
1885	+	fieldOffset("eventCount", ForkJoinPool.class);
1886	+	static final long workerCountsOffset =
1887	+	fieldOffset("workerCounts", ForkJoinPool.class);
1888	+	static final long runControlOffset =
1889	+	fieldOffset("runControl", ForkJoinPool.class);
1890	+	static final long syncStackOffset =
1891	+	fieldOffset("syncStack",ForkJoinPool.class);
1892	+	static final long spareStackOffset =
1893	+	fieldOffset("spareStack", ForkJoinPool.class);
1894	+
1895		private boolean casEventCount(long cmp, long val) {
1896		return UNSAFE.compareAndSwapLong(this, eventCountOffset, cmp, val);
1897		}

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