ViewVC Help

View File | Revision Log | Show Annotations | Download File | Root Listing

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

Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.4 by dl, Mon Jan 12 17:16:18 2009 UTC vs.
Revision 1.11 by jsr166, Tue Jul 21 00:15:13 2009 UTC

#	Line 27 | Line 27 | import java.lang.reflect.*;
27		* (eventually blocking if none exist). This makes them efficient when
28		* most tasks spawn other subtasks (as do most ForkJoinTasks), as well
29		* as the mixed execution of some plain Runnable- or Callable- based
30	<	* activities along with ForkJoinTasks. Otherwise, other
30	>	* activities along with ForkJoinTasks. When setting
31	>	* {@code setAsyncMode}, a ForkJoinPools may also be appropriate for
32	>	* use with fine-grained tasks that are never joined. Otherwise, other
33		* ExecutorService implementations are typically more appropriate
34		* choices.
35		*
#	Line 36 | Line 38 | import java.lang.reflect.*;
38		* adding, suspending, or resuming threads, even if some tasks are
39		* waiting to join others. However, no such adjustments are performed
40		* in the face of blocked IO or other unmanaged synchronization. The
41	<	* nested <code>ManagedBlocker</code> interface enables extension of
41	>	* nested {@code ManagedBlocker} interface enables extension of
42		* the kinds of synchronization accommodated.  The target parallelism
43	<	* level may also be changed dynamically (<code>setParallelism</code>)
44	<	* and dynamically thread construction can be limited using methods
45	<	* <code>setMaximumPoolSize</code> and/or
46	<	* <code>setMaintainsParallelism</code>.
43	>	* level may also be changed dynamically ({@code setParallelism})
44	>	* and thread construction can be limited using methods
45	>	* {@code setMaximumPoolSize} and/or
46	>	* {@code setMaintainsParallelism}.
47		*
48		* <p>In addition to execution and lifecycle control methods, this
49		* class provides status check methods (for example
50	<	* <code>getStealCount</code>) that are intended to aid in developing,
50	>	* {@code getStealCount}) that are intended to aid in developing,
51		* tuning, and monitoring fork/join applications. Also, method
52	<	* <code>toString</code> returns indications of pool state in a
52	>	* {@code toString} returns indications of pool state in a
53		* convenient form for informal monitoring.
54		*
55		* <p><b>Implementation notes</b>: This implementation restricts the
#	Line 79 | Line 81 | public class ForkJoinPool extends Abstra
81		* Returns a new worker thread operating in the given pool.
82		*
83		* @param pool the pool this thread works in
84	<	* @throws NullPointerException if pool is null;
84	>	* @throws NullPointerException if pool is null
85		*/
86		public ForkJoinWorkerThread newThread(ForkJoinPool pool);
87		}
#	Line 131 | Line 133 | public class ForkJoinPool extends Abstra
133		new AtomicInteger();
134
135		/**
136	<	* Array holding all worker threads in the pool. Array size must
137	<	* be a power of two.  Updates and replacements are protected by
138	<	* workerLock, but it is always kept in a consistent enough state
139	<	* to be randomly accessed without locking by workers performing
140	<	* work-stealing.
136	>	* Array holding all worker threads in the pool. Initialized upon
137	>	* first use. Array size must be a power of two.  Updates and
138	>	* replacements are protected by workerLock, but it is always kept
139	>	* in a consistent enough state to be randomly accessed without
140	>	* locking by workers performing work-stealing.
141		*/
142		volatile ForkJoinWorkerThread[] workers;
143
#	Line 151 | Line 153 | public class ForkJoinPool extends Abstra
153
154		/**
155		* The uncaught exception handler used when any worker
156	<	* abrupty terminates
156	>	* abruptly terminates
157		*/
158		private Thread.UncaughtExceptionHandler ueh;
159
#	Line 204 | Line 206 | public class ForkJoinPool extends Abstra
206		private volatile int parallelism;
207
208		/**
209	+	* True if use local fifo, not default lifo, for local polling
210	+	*/
211	+	private volatile boolean locallyFifo;
212	+
213	+	/**
214		* Holds number of total (i.e., created and not yet terminated)
215		* and running (i.e., not blocked on joins or other managed sync)
216		* threads, packed into one int to ensure consistent snapshot when
#	Line 219 | Line 226 | public class ForkJoinPool extends Abstra
226		private static int workerCountsFor(int t, int r) { return (t << 16) + r; }
227
228		/**
229	<	* Add delta (which may be negative) to running count.  This must
229	>	* Adds delta (which may be negative) to running count.  This must
230		* be called before (with negative arg) and after (with positive)
231	<	* any managed synchronization (i.e., mainly, joins)
231	>	* any managed synchronization (i.e., mainly, joins).
232		* @param delta the number to add
233		*/
234		final void updateRunningCount(int delta) {
#	Line 230 | Line 237 | public class ForkJoinPool extends Abstra
237		}
238
239		/**
240	<	* Add delta (which may be negative) to both total and running
240	>	* Adds delta (which may be negative) to both total and running
241		* count.  This must be called upon creation and termination of
242		* worker threads.
243		* @param delta the number to add
#	Line 266 | Line 273 | public class ForkJoinPool extends Abstra
273		/**
274		* Try incrementing active count; fail on contention. Called by
275		* workers before/during executing tasks.
276	<	* @return true on success;
276	>	* @return true on success
277		*/
278		final boolean tryIncrementActiveCount() {
279		int c = runControl;
#	Line 274 | Line 281 | public class ForkJoinPool extends Abstra
281		}
282
283		/**
284	<	* Try decrementing active count; fail on contention.
285	<	* Possibly trigger termination on success
284	>	* Tries decrementing active count; fails on contention.
285	>	* Possibly triggers termination on success.
286		* Called by workers when they can't find tasks.
287		* @return true on success
288		*/
#	Line 290 | Line 297 | public class ForkJoinPool extends Abstra
297		}
298
299		/**
300	<	* Return true if argument represents zero active count and
300	>	* Returns true if argument represents zero active count and
301		* nonzero runstate, which is the triggering condition for
302		* terminating on shutdown.
303		*/
#	Line 326 | Line 333 | public class ForkJoinPool extends Abstra
333		* @throws SecurityException if a security manager exists and
334		*         the caller is not permitted to modify threads
335		*         because it does not hold {@link
336	<	*         java.lang.RuntimePermission}<code>("modifyThread")</code>,
336	>	*         java.lang.RuntimePermission}{@code ("modifyThread")},
337		*/
338		public ForkJoinPool() {
339		this(Runtime.getRuntime().availableProcessors(),
#	Line 334 | Line 341 | public class ForkJoinPool extends Abstra
341		}
342
343		/**
344	<	* Creates a ForkJoinPool with the indicated parellelism level
344	>	* Creates a ForkJoinPool with the indicated parallelism level
345		* threads, and using the default ForkJoinWorkerThreadFactory,
346		* @param parallelism the number of worker threads
347		* @throws IllegalArgumentException if parallelism less than or
#	Line 342 | Line 349 | public class ForkJoinPool extends Abstra
349		* @throws SecurityException if a security manager exists and
350		*         the caller is not permitted to modify threads
351		*         because it does not hold {@link
352	<	*         java.lang.RuntimePermission}<code>("modifyThread")</code>,
352	>	*         java.lang.RuntimePermission}{@code ("modifyThread")},
353		*/
354		public ForkJoinPool(int parallelism) {
355		this(parallelism, defaultForkJoinWorkerThreadFactory);
#	Line 357 | Line 364 | public class ForkJoinPool extends Abstra
364		* @throws SecurityException if a security manager exists and
365		*         the caller is not permitted to modify threads
366		*         because it does not hold {@link
367	<	*         java.lang.RuntimePermission}<code>("modifyThread")</code>,
367	>	*         java.lang.RuntimePermission}{@code ("modifyThread")},
368		*/
369		public ForkJoinPool(ForkJoinWorkerThreadFactory factory) {
370		this(Runtime.getRuntime().availableProcessors(), factory);
#	Line 369 | Line 376 | public class ForkJoinPool extends Abstra
376		* @param parallelism the targeted number of worker threads
377		* @param factory the factory for creating new threads
378		* @throws IllegalArgumentException if parallelism less than or
379	<	* equal to zero, or greater than implementation limit.
379	>	* equal to zero, or greater than implementation limit
380		* @throws NullPointerException if factory is null
381		* @throws SecurityException if a security manager exists and
382		*         the caller is not permitted to modify threads
383		*         because it does not hold {@link
384	<	*         java.lang.RuntimePermission}<code>("modifyThread")</code>,
384	>	*         java.lang.RuntimePermission}{@code ("modifyThread")},
385		*/
386		public ForkJoinPool(int parallelism, ForkJoinWorkerThreadFactory factory) {
387		if (parallelism <= 0 || parallelism > MAX_THREADS)
#	Line 391 | Line 398 | public class ForkJoinPool extends Abstra
398		this.termination = workerLock.newCondition();
399		this.stealCount = new AtomicLong();
400		this.submissionQueue = new LinkedTransferQueue<ForkJoinTask<?>>();
401	<	createAndStartInitialWorkers(parallelism);
401	>	// worker array and workers are lazily constructed
402		}
403
404		/**
#	Line 405 | Line 412 | public class ForkJoinPool extends Abstra
412		if (w != null) {
413		w.poolIndex = index;
414		w.setDaemon(true);
415	+	w.setAsyncMode(locallyFifo);
416		w.setName("ForkJoinPool-" + poolNumber + "-worker-" + index);
417		if (h != null)
418		w.setUncaughtExceptionHandler(h);
#	Line 413 | Line 421 | public class ForkJoinPool extends Abstra
421		}
422
423		/**
424	<	* Return a good size for worker array given pool size.
424	>	* Returns a good size for worker array given pool size.
425		* Currently requires size to be a power of two.
426		*/
427		private static int arraySizeFor(int ps) {
#	Line 421 | Line 429 | public class ForkJoinPool extends Abstra
429		}
430
431		/**
432	<	* Create or resize array if necessary to hold newLength
432	>	* Creates or resizes array if necessary to hold newLength.
433	>	* Call only under exclusion or lock.
434		* @return the array
435		*/
436		private ForkJoinWorkerThread[] ensureWorkerArrayCapacity(int newLength) {
#	Line 439 | Line 448 | public class ForkJoinPool extends Abstra
448		*/
449		private void tryShrinkWorkerArray() {
450		ForkJoinWorkerThread[] ws = workers;
451	<	int len = ws.length;
452	<	int last = len - 1;
453	<	while (last >= 0 && ws[last] == null)
454	<	--last;
455	<	int newLength = arraySizeFor(last+1);
456	<	if (newLength < len)
457	<	workers = Arrays.copyOf(ws, newLength);
451	>	if (ws != null) {
452	>	int len = ws.length;
453	>	int last = len - 1;
454	>	while (last >= 0 && ws[last] == null)
455	>	--last;
456	>	int newLength = arraySizeFor(last+1);
457	>	if (newLength < len)
458	>	workers = Arrays.copyOf(ws, newLength);
459	>	}
460		}
461
462		/**
463	<	* Initial worker array and worker creation and startup. (This
453	<	* must be done under lock to avoid interference by some of the
454	<	* newly started threads while creating others.)
463	>	* Initialize workers if necessary
464		*/
465	<	private void createAndStartInitialWorkers(int ps) {
466	<	final ReentrantLock lock = this.workerLock;
467	<	lock.lock();
468	<	try {
469	<	ForkJoinWorkerThread[] ws = ensureWorkerArrayCapacity(ps);
470	<	for (int i = 0; i < ps; ++i) {
471	<	ForkJoinWorkerThread w = createWorker(i);
472	<	if (w != null) {
473	<	ws[i] = w;
474	<	w.start();
475	<	updateWorkerCount(1);
465	>	final void ensureWorkerInitialization() {
466	>	ForkJoinWorkerThread[] ws = workers;
467	>	if (ws == null) {
468	>	final ReentrantLock lock = this.workerLock;
469	>	lock.lock();
470	>	try {
471	>	ws = workers;
472	>	if (ws == null) {
473	>	int ps = parallelism;
474	>	ws = ensureWorkerArrayCapacity(ps);
475	>	for (int i = 0; i < ps; ++i) {
476	>	ForkJoinWorkerThread w = createWorker(i);
477	>	if (w != null) {
478	>	ws[i] = w;
479	>	w.start();
480	>	updateWorkerCount(1);
481	>	}
482	>	}
483		}
484	+	} finally {
485	+	lock.unlock();
486		}
469	–	} finally {
470	–	lock.unlock();
487		}
488		}
489
#	Line 513 | Line 529 | public class ForkJoinPool extends Abstra
529		private <T> void doSubmit(ForkJoinTask<T> task) {
530		if (isShutdown())
531		throw new RejectedExecutionException();
532	+	if (workers == null)
533	+	ensureWorkerInitialization();
534		submissionQueue.offer(task);
535		signalIdleWorkers();
536		}
#	Line 671 | Line 689 | public class ForkJoinPool extends Abstra
689		* @throws SecurityException if a security manager exists and
690		*         the caller is not permitted to modify threads
691		*         because it does not hold {@link
692	<	*         java.lang.RuntimePermission}<code>("modifyThread")</code>,
692	>	*         java.lang.RuntimePermission}{@code ("modifyThread")},
693		*/
694		public Thread.UncaughtExceptionHandler
695		setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler h) {
#	Line 683 | Line 701 | public class ForkJoinPool extends Abstra
701		old = ueh;
702		ueh = h;
703		ForkJoinWorkerThread[] ws = workers;
704	<	for (int i = 0; i < ws.length; ++i) {
705	<	ForkJoinWorkerThread w = ws[i];
706	<	if (w != null)
707	<	w.setUncaughtExceptionHandler(h);
704	>	if (ws != null) {
705	>	for (int i = 0; i < ws.length; ++i) {
706	>	ForkJoinWorkerThread w = ws[i];
707	>	if (w != null)
708	>	w.setUncaughtExceptionHandler(h);
709	>	}
710		}
711		} finally {
712		lock.unlock();
#	Line 696 | Line 716 | public class ForkJoinPool extends Abstra
716
717
718		/**
719	<	* Sets the target paralleism level of this pool.
719	>	* Sets the target parallelism level of this pool.
720		* @param parallelism the target parallelism
721		* @throws IllegalArgumentException if parallelism less than or
722	<	* equal to zero or greater than maximum size bounds.
722	>	* equal to zero or greater than maximum size bounds
723		* @throws SecurityException if a security manager exists and
724		*         the caller is not permitted to modify threads
725		*         because it does not hold {@link
726	<	*         java.lang.RuntimePermission}<code>("modifyThread")</code>,
726	>	*         java.lang.RuntimePermission}{@code ("modifyThread")},
727		*/
728		public void setParallelism(int parallelism) {
729		checkPermission();
#	Line 738 | Line 758 | public class ForkJoinPool extends Abstra
758		/**
759		* Returns the number of worker threads that have started but not
760		* yet terminated.  This result returned by this method may differ
761	<	* from <code>getParallelism</code> when threads are created to
761	>	* from {@code getParallelism} when threads are created to
762		* maintain parallelism when others are cooperatively blocked.
763		*
764		* @return the number of worker threads
#	Line 762 | Line 782 | public class ForkJoinPool extends Abstra
782		* Setting this value has no effect on current pool size. It
783		* controls construction of new threads.
784		* @throws IllegalArgumentException if negative or greater then
785	<	* internal implementation limit.
785	>	* internal implementation limit
786		*/
787		public void setMaximumPoolSize(int newMax) {
788		if (newMax < 0 || newMax > MAX_THREADS)
#	Line 793 | Line 813 | public class ForkJoinPool extends Abstra
813		}
814
815		/**
816	+	* Establishes local first-in-first-out scheduling mode for forked
817	+	* tasks that are never joined. This mode may be more appropriate
818	+	* than default locally stack-based mode in applications in which
819	+	* worker threads only process asynchronous tasks.  This method is
820	+	* designed to be invoked only when pool is quiescent, and
821	+	* typically only before any tasks are submitted. The effects of
822	+	* invocations at other times may be unpredictable.
823	+	*
824	+	* @param async if true, use locally FIFO scheduling
825	+	* @return the previous mode
826	+	*/
827	+	public boolean setAsyncMode(boolean async) {
828	+	boolean oldMode = locallyFifo;
829	+	locallyFifo = async;
830	+	ForkJoinWorkerThread[] ws = workers;
831	+	if (ws != null) {
832	+	for (int i = 0; i < ws.length; ++i) {
833	+	ForkJoinWorkerThread t = ws[i];
834	+	if (t != null)
835	+	t.setAsyncMode(async);
836	+	}
837	+	}
838	+	return oldMode;
839	+	}
840	+
841	+	/**
842	+	* Returns true if this pool uses local first-in-first-out
843	+	* scheduling mode for forked tasks that are never joined.
844	+	*
845	+	* @return true if this pool uses async mode
846	+	*/
847	+	public boolean getAsyncMode() {
848	+	return locallyFifo;
849	+	}
850	+
851	+	/**
852		* Returns an estimate of the number of worker threads that are
853		* not blocked waiting to join tasks or for other managed
854		* synchronization.
#	Line 807 | Line 863 | public class ForkJoinPool extends Abstra
863		* Returns an estimate of the number of threads that are currently
864		* stealing or executing tasks. This method may overestimate the
865		* number of active threads.
866	<	* @return the number of active threads.
866	>	* @return the number of active threads
867		*/
868		public int getActiveThreadCount() {
869		return activeCountOf(runControl);
#	Line 817 | Line 873 | public class ForkJoinPool extends Abstra
873		* Returns an estimate of the number of threads that are currently
874		* idle waiting for tasks. This method may underestimate the
875		* number of idle threads.
876	<	* @return the number of idle threads.
876	>	* @return the number of idle threads
877		*/
878		final int getIdleThreadCount() {
879		int c = runningCountOf(workerCounts) - activeCountOf(runControl);
#	Line 846 | Line 902 | public class ForkJoinPool extends Abstra
902		* tuning fork/join programs: In general, steal counts should be
903		* high enough to keep threads busy, but low enough to avoid
904		* overhead and contention across threads.
905	<	* @return the number of steals.
905	>	* @return the number of steals
906		*/
907		public long getStealCount() {
908		return stealCount.get();
#	Line 869 | Line 925 | public class ForkJoinPool extends Abstra
925		* an approximation, obtained by iterating across all threads in
926		* the pool. This method may be useful for tuning task
927		* granularities.
928	<	* @return the number of queued tasks.
928	>	* @return the number of queued tasks
929		*/
930		public long getQueuedTaskCount() {
931		long count = 0;
932		ForkJoinWorkerThread[] ws = workers;
933	<	for (int i = 0; i < ws.length; ++i) {
934	<	ForkJoinWorkerThread t = ws[i];
935	<	if (t != null)
936	<	count += t.getQueueSize();
933	>	if (ws != null) {
934	>	for (int i = 0; i < ws.length; ++i) {
935	>	ForkJoinWorkerThread t = ws[i];
936	>	if (t != null)
937	>	count += t.getQueueSize();
938	>	}
939		}
940		return count;
941		}
#	Line 886 | Line 944 | public class ForkJoinPool extends Abstra
944		* Returns an estimate of the number tasks submitted to this pool
945		* that have not yet begun executing. This method takes time
946		* proportional to the number of submissions.
947	<	* @return the number of queued submissions.
947	>	* @return the number of queued submissions
948		*/
949		public int getQueuedSubmissionCount() {
950		return submissionQueue.size();
#	Line 895 | Line 953 | public class ForkJoinPool extends Abstra
953		/**
954		* Returns true if there are any tasks submitted to this pool
955		* that have not yet begun executing.
956	<	* @return <code>true</code> if there are any queued submissions.
956	>	* @return {@code true} if there are any queued submissions
957		*/
958		public boolean hasQueuedSubmissions() {
959		return !submissionQueue.isEmpty();
#	Line 912 | Line 970 | public class ForkJoinPool extends Abstra
970		}
971
972		/**
973	+	* Removes all available unexecuted submitted and forked tasks
974	+	* from scheduling queues and adds them to the given collection,
975	+	* without altering their execution status. These may include
976	+	* artificially generated or wrapped tasks. This method is designed
977	+	* to be invoked only when the pool is known to be
978	+	* quiescent. Invocations at other times may not remove all
979	+	* tasks. A failure encountered while attempting to add elements
980	+	* to collection {@code c} may result in elements being in
981	+	* neither, either or both collections when the associated
982	+	* exception is thrown.  The behavior of this operation is
983	+	* undefined if the specified collection is modified while the
984	+	* operation is in progress.
985	+	* @param c the collection to transfer elements into
986	+	* @return the number of elements transferred
987	+	*/
988	+	protected int drainTasksTo(Collection<ForkJoinTask<?>> c) {
989	+	int n = submissionQueue.drainTo(c);
990	+	ForkJoinWorkerThread[] ws = workers;
991	+	if (ws != null) {
992	+	for (int i = 0; i < ws.length; ++i) {
993	+	ForkJoinWorkerThread w = ws[i];
994	+	if (w != null)
995	+	n += w.drainTasksTo(c);
996	+	}
997	+	}
998	+	return n;
999	+	}
1000	+
1001	+	/**
1002		* Returns a string identifying this pool, as well as its state,
1003		* including indications of run state, parallelism level, and
1004		* worker and task counts.
#	Line 958 | Line 1045 | public class ForkJoinPool extends Abstra
1045		* @throws SecurityException if a security manager exists and
1046		*         the caller is not permitted to modify threads
1047		*         because it does not hold {@link
1048	<	*         java.lang.RuntimePermission}<code>("modifyThread")</code>,
1048	>	*         java.lang.RuntimePermission}{@code ("modifyThread")},
1049		*/
1050		public void shutdown() {
1051		checkPermission();
#	Line 972 | Line 1059 | public class ForkJoinPool extends Abstra
1059		* waiting tasks.  Tasks that are in the process of being
1060		* submitted or executed concurrently during the course of this
1061		* method may or may not be rejected. Unlike some other executors,
1062	<	* this method cancels rather than collects non-executed tasks,
1063	<	* so always returns an empty list.
1062	>	* this method cancels rather than collects non-executed tasks
1063	>	* upon termination, so always returns an empty list. However, you
1064	>	* can use method {@code drainTasksTo} before invoking this
1065	>	* method to transfer unexecuted tasks to another collection.
1066		* @return an empty list
1067		* @throws SecurityException if a security manager exists and
1068		*         the caller is not permitted to modify threads
1069		*         because it does not hold {@link
1070	<	*         java.lang.RuntimePermission}<code>("modifyThread")</code>,
1070	>	*         java.lang.RuntimePermission}{@code ("modifyThread")},
1071		*/
1072		public List<Runnable> shutdownNow() {
1073		checkPermission();
#	Line 987 | Line 1076 | public class ForkJoinPool extends Abstra
1076		}
1077
1078		/**
1079	<	* Returns <code>true</code> if all tasks have completed following shut down.
1079	>	* Returns {@code true} if all tasks have completed following shut down.
1080		*
1081	<	* @return <code>true</code> if all tasks have completed following shut down
1081	>	* @return {@code true} if all tasks have completed following shut down
1082		*/
1083		public boolean isTerminated() {
1084		return runStateOf(runControl) == TERMINATED;
1085		}
1086
1087		/**
1088	<	* Returns <code>true</code> if the process of termination has
1088	>	* Returns {@code true} if the process of termination has
1089		* commenced but possibly not yet completed.
1090		*
1091	<	* @return <code>true</code> if terminating
1091	>	* @return {@code true} if terminating
1092		*/
1093		public boolean isTerminating() {
1094		return runStateOf(runControl) >= TERMINATING;
1095		}
1096
1097		/**
1098	<	* Returns <code>true</code> if this pool has been shut down.
1098	>	* Returns {@code true} if this pool has been shut down.
1099		*
1100	<	* @return <code>true</code> if this pool has been shut down
1100	>	* @return {@code true} if this pool has been shut down
1101		*/
1102		public boolean isShutdown() {
1103		return runStateOf(runControl) >= SHUTDOWN;
#	Line 1021 | Line 1110 | public class ForkJoinPool extends Abstra
1110		*
1111		* @param timeout the maximum time to wait
1112		* @param unit the time unit of the timeout argument
1113	<	* @return <code>true</code> if this executor terminated and
1114	<	*         <code>false</code> if the timeout elapsed before termination
1113	>	* @return {@code true} if this executor terminated and
1114	>	*         {@code false} if the timeout elapsed before termination
1115		* @throws InterruptedException if interrupted while waiting
1116		*/
1117		public boolean awaitTermination(long timeout, TimeUnit unit)
#	Line 1058 | Line 1147 | public class ForkJoinPool extends Abstra
1147		lock.lock();
1148		try {
1149		ForkJoinWorkerThread[] ws = workers;
1150	<	int idx = w.poolIndex;
1151	<	if (idx >= 0 && idx < ws.length && ws[idx] == w)
1152	<	ws[idx] = null;
1153	<	if (totalCountOf(workerCounts) == 0) {
1154	<	terminate(); // no-op if already terminating
1155	<	transitionRunStateTo(TERMINATED);
1156	<	termination.signalAll();
1157	<	}
1158	<	else if (!isTerminating()) {
1159	<	tryShrinkWorkerArray();
1160	<	tryResumeSpare(true); // allow replacement
1150	>	if (ws != null) {
1151	>	int idx = w.poolIndex;
1152	>	if (idx >= 0 && idx < ws.length && ws[idx] == w)
1153	>	ws[idx] = null;
1154	>	if (totalCountOf(workerCounts) == 0) {
1155	>	terminate(); // no-op if already terminating
1156	>	transitionRunStateTo(TERMINATED);
1157	>	termination.signalAll();
1158	>	}
1159	>	else if (!isTerminating()) {
1160	>	tryShrinkWorkerArray();
1161	>	tryResumeSpare(true); // allow replacement
1162	>	}
1163		}
1164		} finally {
1165		lock.unlock();
#	Line 1092 | Line 1183 | public class ForkJoinPool extends Abstra
1183		}
1184
1185		/**
1186	<	* Possibly terminate when on shutdown state
1186	>	* Possibly terminates when on shutdown state.
1187		*/
1188		private void terminateOnShutdown() {
1189		if (!hasQueuedSubmissions() && canTerminateOnShutdown(runControl))
#	Line 1100 | Line 1191 | public class ForkJoinPool extends Abstra
1191		}
1192
1193		/**
1194	<	* Clear out and cancel submissions
1194	>	* Clears out and cancels submissions.
1195		*/
1196		private void cancelQueuedSubmissions() {
1197		ForkJoinTask<?> task;
#	Line 1109 | Line 1200 | public class ForkJoinPool extends Abstra
1200		}
1201
1202		/**
1203	<	* Clean out worker queues.
1203	>	* Cleans out worker queues.
1204		*/
1205		private void cancelQueuedWorkerTasks() {
1206		final ReentrantLock lock = this.workerLock;
1207		lock.lock();
1208		try {
1209		ForkJoinWorkerThread[] ws = workers;
1210	<	for (int i = 0; i < ws.length; ++i) {
1211	<	ForkJoinWorkerThread t = ws[i];
1212	<	if (t != null)
1213	<	t.cancelTasks();
1210	>	if (ws != null) {
1211	>	for (int i = 0; i < ws.length; ++i) {
1212	>	ForkJoinWorkerThread t = ws[i];
1213	>	if (t != null)
1214	>	t.cancelTasks();
1215	>	}
1216		}
1217		} finally {
1218		lock.unlock();
#	Line 1127 | Line 1220 | public class ForkJoinPool extends Abstra
1220		}
1221
1222		/**
1223	<	* Set each worker's status to terminating. Requires lock to avoid
1224	<	* conflicts with add/remove
1223	>	* Sets each worker's status to terminating. Requires lock to avoid
1224	>	* conflicts with add/remove.
1225		*/
1226		private void stopAllWorkers() {
1227		final ReentrantLock lock = this.workerLock;
1228		lock.lock();
1229		try {
1230		ForkJoinWorkerThread[] ws = workers;
1231	<	for (int i = 0; i < ws.length; ++i) {
1232	<	ForkJoinWorkerThread t = ws[i];
1233	<	if (t != null)
1234	<	t.shutdownNow();
1231	>	if (ws != null) {
1232	>	for (int i = 0; i < ws.length; ++i) {
1233	>	ForkJoinWorkerThread t = ws[i];
1234	>	if (t != null)
1235	>	t.shutdownNow();
1236	>	}
1237		}
1238		} finally {
1239		lock.unlock();
#	Line 1146 | Line 1241 | public class ForkJoinPool extends Abstra
1241		}
1242
1243		/**
1244	<	* Interrupt all unterminated workers.  This is not required for
1244	>	* Interrupts all unterminated workers.  This is not required for
1245		* sake of internal control, but may help unstick user code during
1246		* shutdown.
1247		*/
#	Line 1155 | Line 1250 | public class ForkJoinPool extends Abstra
1250		lock.lock();
1251		try {
1252		ForkJoinWorkerThread[] ws = workers;
1253	<	for (int i = 0; i < ws.length; ++i) {
1254	<	ForkJoinWorkerThread t = ws[i];
1255	<	if (t != null && !t.isTerminated()) {
1256	<	try {
1257	<	t.interrupt();
1258	<	} catch (SecurityException ignore) {
1253	>	if (ws != null) {
1254	>	for (int i = 0; i < ws.length; ++i) {
1255	>	ForkJoinWorkerThread t = ws[i];
1256	>	if (t != null && !t.isTerminated()) {
1257	>	try {
1258	>	t.interrupt();
1259	>	} catch (SecurityException ignore) {
1260	>	}
1261		}
1262		}
1263		}
#	Line 1214 | Line 1311 | public class ForkJoinPool extends Abstra
1311		}
1312
1313		/**
1314	<	* Wake up waiter, returning false if known to already
1314	>	* Wakes up waiter, returning false if known to already
1315		*/
1316		boolean signal() {
1317		ForkJoinWorkerThread t = thread;
#	Line 1226 | Line 1323 | public class ForkJoinPool extends Abstra
1323		}
1324
1325		/**
1326	<	* Await release on sync
1326	>	* Awaits release on sync.
1327		*/
1328		void awaitSyncRelease(ForkJoinPool p) {
1329		while (thread != null && !p.syncIsReleasable(this))
#	Line 1234 | Line 1331 | public class ForkJoinPool extends Abstra
1331		}
1332
1333		/**
1334	<	* Await resumption as spare
1334	>	* Awaits resumption as spare.
1335		*/
1336		void awaitSpareRelease() {
1337		while (thread != null) {
#	Line 1274 | Line 1371 | public class ForkJoinPool extends Abstra
1371		}
1372
1373		/**
1374	<	* Signal threads waiting to poll a task. Because method sync
1374	>	* Signals threads waiting to poll a task. Because method sync
1375		* rechecks availability, it is OK to only proceed if queue
1376		* appears to be non-empty, and OK to skip under contention to
1377		* increment count (since some other thread succeeded).
#	Line 1302 | Line 1399 | public class ForkJoinPool extends Abstra
1399		long prev = w.lastEventCount;
1400		WaitQueueNode node = null;
1401		WaitQueueNode h;
1402	<	while (eventCount == prev &&
1402	>	while (eventCount == prev &&
1403		((h = syncStack) == null || h.count == prev)) {
1404		if (node == null)
1405		node = new WaitQueueNode(prev, w);
#	Line 1324 | Line 1421 | public class ForkJoinPool extends Abstra
1421		*  - on signal (thread == null)
1422		*  - on event count advance (winning race to notify vs signaller)
1423		*  - on Interrupt
1424	<	*  - if the first queued node, we find work available
1425	<	* If node was not signalled and event count not advanced on exit,
1424	>	*  - if the first queued node, we find work available
1425	>	* If node was not signalled and event count not advanced on exit,
1426		* then we also help advance event count.
1427		* @return true if node can be released
1428		*/
#	Line 1361 | Line 1458 | public class ForkJoinPool extends Abstra
1458		//  Parallelism maintenance
1459
1460		/**
1461	<	* Decrement running count; if too low, add spare.
1461	>	* Decrements running count; if too low, adds spare.
1462		*
1463		* Conceptually, all we need to do here is add or resume a
1464		* spare thread when one is about to block (and remove or
#	Line 1381 | Line 1478 | public class ForkJoinPool extends Abstra
1478		* only be suspended or removed when they are idle, not
1479		* immediately when they aren't needed. So adding threads will
1480		* raise parallelism level for longer than necessary.  Also,
1481	<	* FJ applications often enounter highly transient peaks when
1481	>	* FJ applications often encounter highly transient peaks when
1482		* many threads are blocked joining, but for less time than it
1483		* takes to create or resume spares.
1484		*
#	Line 1446 | Line 1543 | public class ForkJoinPool extends Abstra
1543		return (tc < maxPoolSize &&
1544		(rc == 0 || totalSurplus < 0 ||
1545		(maintainParallelism &&
1546	<	runningDeficit > totalSurplus &&
1546	>	runningDeficit > totalSurplus &&
1547		ForkJoinWorkerThread.hasQueuedTasks(workers))));
1548		}
1549	<
1549	>
1550		/**
1551	<	* Add a spare worker if lock available and no more than the
1552	<	* expected numbers of threads exist
1551	>	* Adds a spare worker if lock available and no more than the
1552	>	* expected numbers of threads exist.
1553		* @return true if successful
1554		*/
1555		private boolean tryAddSpare(int expectedCounts) {
#	Line 1485 | Line 1582 | public class ForkJoinPool extends Abstra
1582		}
1583
1584		/**
1585	<	* Add the kth spare worker. On entry, pool coounts are already
1585	>	* Adds the kth spare worker. On entry, pool counts are already
1586		* adjusted to reflect addition.
1587		*/
1588		private void createAndStartSpare(int k) {
#	Line 1507 | Line 1604 | public class ForkJoinPool extends Abstra
1604		}
1605
1606		/**
1607	<	* Suspend calling thread w if there are excess threads.  Called
1608	<	* only from sync.  Spares are enqueued in a Treiber stack
1609	<	* using the same WaitQueueNodes as barriers.  They are resumed
1610	<	* mainly in preJoin, but are also woken on pool events that
1611	<	* require all threads to check run state.
1607	>	* Suspends calling thread w if there are excess threads.  Called
1608	>	* only from sync.  Spares are enqueued in a Treiber stack using
1609	>	* the same WaitQueueNodes as barriers.  They are resumed mainly
1610	>	* in preJoin, but are also woken on pool events that require all
1611	>	* threads to check run state.
1612		* @param w the caller
1613		*/
1614		private boolean suspendIfSpare(ForkJoinWorkerThread w) {
#	Line 1532 | Line 1629 | public class ForkJoinPool extends Abstra
1629		}
1630
1631		/**
1632	<	* Try to pop and resume a spare thread.
1632	>	* Tries to pop and resume a spare thread.
1633		* @param updateCount if true, increment running count on success
1634		* @return true if successful
1635		*/
#	Line 1550 | Line 1647 | public class ForkJoinPool extends Abstra
1647		}
1648
1649		/**
1650	<	* Pop and resume all spare threads. Same idea as ensureSync.
1650	>	* Pops and resumes all spare threads. Same idea as ensureSync.
1651		* @return true if any spares released
1652		*/
1653		private boolean resumeAllSpares() {
#	Line 1568 | Line 1665 | public class ForkJoinPool extends Abstra
1665		}
1666
1667		/**
1668	<	* Pop and shutdown excessive spare threads. Call only while
1668	>	* Pops and shuts down excessive spare threads. Call only while
1669		* holding lock. This is not guaranteed to eliminate all excess
1670		* threads, only those suspended as spares, which are the ones
1671		* unlikely to be needed in the future.
#	Line 1593 | Line 1690 | public class ForkJoinPool extends Abstra
1690		/**
1691		* Interface for extending managed parallelism for tasks running
1692		* in ForkJoinPools. A ManagedBlocker provides two methods.
1693	<	* Method <code>isReleasable</code> must return true if blocking is not
1694	<	* necessary. Method <code>block</code> blocks the current thread
1693	>	* Method {@code isReleasable} must return true if blocking is not
1694	>	* necessary. Method {@code block} blocks the current thread
1695		* if necessary (perhaps internally invoking isReleasable before
1696		* actually blocking.).
1697		* <p>For example, here is a ManagedBlocker based on a
#	Line 1620 | Line 1717 | public class ForkJoinPool extends Abstra
1717		* Possibly blocks the current thread, for example waiting for
1718		* a lock or condition.
1719		* @return true if no additional blocking is necessary (i.e.,
1720	<	* if isReleasable would return true).
1720	>	* if isReleasable would return true)
1721		* @throws InterruptedException if interrupted while waiting
1722	<	* (the method is not required to do so, but is allowe to).
1722	>	* (the method is not required to do so, but is allowed to).
1723		*/
1724		boolean block() throws InterruptedException;
1725
#	Line 1637 | Line 1734 | public class ForkJoinPool extends Abstra
1734		* is a ForkJoinWorkerThread, this method possibly arranges for a
1735		* spare thread to be activated if necessary to ensure parallelism
1736		* while the current thread is blocked.  If
1737	<	* <code>maintainParallelism</code> is true and the pool supports
1737	>	* {@code maintainParallelism} is true and the pool supports
1738		* it ({@link #getMaintainsParallelism}), this method attempts to
1739		* maintain the pool's nominal parallelism. Otherwise if activates
1740		* a thread only if necessary to avoid complete starvation. This
#	Line 1659 | Line 1756 | public class ForkJoinPool extends Abstra
1756		* attempt to maintain the pool's nominal parallelism; otherwise
1757		* activate a thread only if necessary to avoid complete
1758		* starvation.
1759	<	* @throws InterruptedException if blocker.block did so.
1759	>	* @throws InterruptedException if blocker.block did so
1760		*/
1761		public static void managedBlock(ManagedBlocker blocker,
1762		boolean maintainParallelism)
#	Line 1696 | Line 1793 | public class ForkJoinPool extends Abstra
1793
1794
1795		// Temporary Unsafe mechanics for preliminary release
1796	+	private static Unsafe getUnsafe() throws Throwable {
1797	+	try {
1798	+	return Unsafe.getUnsafe();
1799	+	} catch (SecurityException se) {
1800	+	try {
1801	+	return java.security.AccessController.doPrivileged
1802	+	(new java.security.PrivilegedExceptionAction<Unsafe>() {
1803	+	public Unsafe run() throws Exception {
1804	+	return getUnsafePrivileged();
1805	+	}});
1806	+	} catch (java.security.PrivilegedActionException e) {
1807	+	throw e.getCause();
1808	+	}
1809	+	}
1810	+	}
1811	+
1812	+	private static Unsafe getUnsafePrivileged()
1813	+	throws NoSuchFieldException, IllegalAccessException {
1814	+	Field f = Unsafe.class.getDeclaredField("theUnsafe");
1815	+	f.setAccessible(true);
1816	+	return (Unsafe) f.get(null);
1817	+	}
1818	+
1819	+	private static long fieldOffset(String fieldName)
1820	+	throws NoSuchFieldException {
1821	+	return _unsafe.objectFieldOffset
1822	+	(ForkJoinPool.class.getDeclaredField(fieldName));
1823	+	}
1824
1825		static final Unsafe _unsafe;
1826		static final long eventCountOffset;
#	Line 1706 | Line 1831 | public class ForkJoinPool extends Abstra
1831
1832		static {
1833		try {
1834	<	if (ForkJoinPool.class.getClassLoader() != null) {
1835	<	Field f = Unsafe.class.getDeclaredField("theUnsafe");
1836	<	f.setAccessible(true);
1837	<	_unsafe = (Unsafe)f.get(null);
1838	<	}
1839	<	else
1840	<	_unsafe = Unsafe.getUnsafe();
1716	<	eventCountOffset = _unsafe.objectFieldOffset
1717	<	(ForkJoinPool.class.getDeclaredField("eventCount"));
1718	<	workerCountsOffset = _unsafe.objectFieldOffset
1719	<	(ForkJoinPool.class.getDeclaredField("workerCounts"));
1720	<	runControlOffset = _unsafe.objectFieldOffset
1721	<	(ForkJoinPool.class.getDeclaredField("runControl"));
1722	<	syncStackOffset = _unsafe.objectFieldOffset
1723	<	(ForkJoinPool.class.getDeclaredField("syncStack"));
1724	<	spareStackOffset = _unsafe.objectFieldOffset
1725	<	(ForkJoinPool.class.getDeclaredField("spareStack"));
1726	<	} catch (Exception e) {
1834	>	_unsafe = getUnsafe();
1835	>	eventCountOffset = fieldOffset("eventCount");
1836	>	workerCountsOffset = fieldOffset("workerCounts");
1837	>	runControlOffset = fieldOffset("runControl");
1838	>	syncStackOffset = fieldOffset("syncStack");
1839	>	spareStackOffset = fieldOffset("spareStack");
1840	>	} catch (Throwable e) {
1841		throw new RuntimeException("Could not initialize intrinsics", e);
1842		}
1843		}

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines