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 1.12 by jsr166, Tue Jul 21 18:11:44 2009 UTC vs.
Revision 1.23 by dl, Sat Jul 25 15:50:57 2009 UTC

#	Line 5 | Line 5
5		*/
6
7		package jsr166y;
8	<	import java.util.*;
8	>
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.*;
10	>
11	>	import java.util.ArrayList;
12	>	import java.util.Arrays;
13	>	import java.util.Collection;
14	>	import java.util.Collections;
15	>	import java.util.List;
16	>	import java.util.concurrent.locks.Condition;
17	>	import java.util.concurrent.locks.LockSupport;
18	>	import java.util.concurrent.locks.ReentrantLock;
19	>	import java.util.concurrent.atomic.AtomicInteger;
20	>	import java.util.concurrent.atomic.AtomicLong;
21
22		/**
23		* An {@link ExecutorService} for running {@link ForkJoinTask}s.  A
#	Line 56 | Line 63 | import java.lang.reflect.*;
63		* maximum number of running threads to 32767. Attempts to create
64		* pools with greater than the maximum result in
65		* IllegalArgumentExceptions.
66	+	*
67	+	* @since 1.7
68	+	* @author Doug Lea
69		*/
70		public class ForkJoinPool extends AbstractExecutorService {
71
#	Line 87 | Line 97 | public class ForkJoinPool extends Abstra
97		}
98
99		/**
100	<	* Default ForkJoinWorkerThreadFactory implementation, creates a
100	>	* Default ForkJoinWorkerThreadFactory implementation; creates a
101		* new ForkJoinWorkerThread.
102		*/
103		static class  DefaultForkJoinWorkerThreadFactory
#	Line 181 | Line 191 | public class ForkJoinPool extends Abstra
191		private final LinkedTransferQueue<ForkJoinTask<?>> submissionQueue;
192
193		/**
194	<	* Head of Treiber stack for barrier sync. See below for explanation
194	>	* Head of Treiber stack for barrier sync. See below for explanation.
195		*/
196		private volatile WaitQueueNode syncStack;
197
#	Line 216 | Line 226 | public class ForkJoinPool extends Abstra
226		* threads, packed into one int to ensure consistent snapshot when
227		* making decisions about creating and suspending spare
228		* threads. Updated only by CAS.  Note: CASes in
229	<	* updateRunningCount and preJoin running active count is in low
230	<	* word, so need to be modified if this changes
229	>	* updateRunningCount and preJoin assume that running active count
230	>	* is in low word, so need to be modified if this changes.
231		*/
232		private volatile int workerCounts;
233
#	Line 229 | Line 239 | public class ForkJoinPool extends Abstra
239		* Adds delta (which may be negative) to running count.  This must
240		* be called before (with negative arg) and after (with positive)
241		* any managed synchronization (i.e., mainly, joins).
242	+	*
243		* @param delta the number to add
244		*/
245		final void updateRunningCount(int delta) {
246		int s;
247	<	do;while (!casWorkerCounts(s = workerCounts, s + delta));
247	>	do {} while (!casWorkerCounts(s = workerCounts, s + delta));
248		}
249
250		/**
251		* Adds delta (which may be negative) to both total and running
252		* count.  This must be called upon creation and termination of
253		* worker threads.
254	+	*
255		* @param delta the number to add
256		*/
257		private void updateWorkerCount(int delta) {
258		int d = delta + (delta << 16); // add to both lo and hi parts
259		int s;
260	<	do;while (!casWorkerCounts(s = workerCounts, s + d));
260	>	do {} while (!casWorkerCounts(s = workerCounts, s + d));
261		}
262
263		/**
#	Line 271 | Line 283 | public class ForkJoinPool extends Abstra
283		private static int runControlFor(int r, int a)   { return (r << 16) + a; }
284
285		/**
286	<	* Try incrementing active count; fail on contention. Called by
287	<	* workers before/during executing tasks.
286	>	* Tries incrementing active count; fails on contention.
287	>	* Called by workers before/during executing tasks.
288	>	*
289		* @return true on success
290		*/
291		final boolean tryIncrementActiveCount() {
#	Line 284 | Line 297 | public class ForkJoinPool extends Abstra
297		* Tries decrementing active count; fails on contention.
298		* Possibly triggers termination on success.
299		* Called by workers when they can't find tasks.
300	+	*
301		* @return true on success
302		*/
303		final boolean tryDecrementActiveCount() {
#	Line 302 | Line 316 | public class ForkJoinPool extends Abstra
316		* terminating on shutdown.
317		*/
318		private static boolean canTerminateOnShutdown(int c) {
319	<	return ((c & -c) >>> 16) != 0; // i.e. least bit is nonzero runState bit
319	>	// i.e. least bit is nonzero runState bit
320	>	return ((c & -c) >>> 16) != 0;
321		}
322
323		/**
#	Line 328 | Line 343 | public class ForkJoinPool extends Abstra
343
344		/**
345		* Creates a ForkJoinPool with a pool size equal to the number of
346	<	* processors available on the system and using the default
347	<	* ForkJoinWorkerThreadFactory,
346	>	* processors available on the system, using the default
347	>	* ForkJoinWorkerThreadFactory.
348	>	*
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")},
352	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
353		*/
354		public ForkJoinPool() {
355		this(Runtime.getRuntime().availableProcessors(),
#	Line 342 | Line 358 | public class ForkJoinPool extends Abstra
358
359		/**
360		* Creates a ForkJoinPool with the indicated parallelism level
361	<	* threads, and using the default ForkJoinWorkerThreadFactory,
361	>	* threads and using the default ForkJoinWorkerThreadFactory.
362	>	*
363		* @param parallelism the number of worker threads
364		* @throws IllegalArgumentException if parallelism less than or
365		* equal to zero
366		* @throws SecurityException if a security manager exists and
367		*         the caller is not permitted to modify threads
368		*         because it does not hold {@link
369	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
369	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
370		*/
371		public ForkJoinPool(int parallelism) {
372		this(parallelism, defaultForkJoinWorkerThreadFactory);
#	Line 358 | Line 375 | public class ForkJoinPool extends Abstra
375		/**
376		* Creates a ForkJoinPool with parallelism equal to the number of
377		* processors available on the system and using the given
378	<	* ForkJoinWorkerThreadFactory,
378	>	* ForkJoinWorkerThreadFactory.
379	>	*
380		* @param factory the factory for creating new threads
381		* @throws NullPointerException if factory is null
382		* @throws SecurityException if a security manager exists and
383		*         the caller is not permitted to modify threads
384		*         because it does not hold {@link
385	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
385	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
386		*/
387		public ForkJoinPool(ForkJoinWorkerThreadFactory factory) {
388		this(Runtime.getRuntime().availableProcessors(), factory);
#	Line 381 | Line 399 | public class ForkJoinPool extends Abstra
399		* @throws SecurityException if a security manager exists and
400		*         the caller is not permitted to modify threads
401		*         because it does not hold {@link
402	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
402	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
403		*/
404		public ForkJoinPool(int parallelism, ForkJoinWorkerThreadFactory factory) {
405		if (parallelism <= 0 || parallelism > MAX_THREADS)
#	Line 402 | Line 420 | public class ForkJoinPool extends Abstra
420		}
421
422		/**
423	<	* Create new worker using factory.
423	>	* Creates a new worker thread using factory.
424	>	*
425		* @param index the index to assign worker
426		* @return new worker, or null of factory failed
427		*/
#	Line 424 | Line 443 | public class ForkJoinPool extends Abstra
443		* Returns a good size for worker array given pool size.
444		* Currently requires size to be a power of two.
445		*/
446	<	private static int arraySizeFor(int ps) {
447	<	return ps <= 1? 1 : (1 << (32 - Integer.numberOfLeadingZeros(ps-1)));
446	>	private static int arraySizeFor(int poolSize) {
447	>	return (poolSize <= 1) ? 1 :
448	>	(1 << (32 - Integer.numberOfLeadingZeros(poolSize-1)));
449		}
450
451		/**
452		* Creates or resizes array if necessary to hold newLength.
453	<	* Call only under exclusion or lock.
453	>	* Call only under exclusion.
454	>	*
455		* @return the array
456		*/
457		private ForkJoinWorkerThread[] ensureWorkerArrayCapacity(int newLength) {
#	Line 444 | Line 465 | public class ForkJoinPool extends Abstra
465		}
466
467		/**
468	<	* Try to shrink workers into smaller array after one or more terminate
468	>	* Tries to shrink workers into smaller array after one or more terminate.
469		*/
470		private void tryShrinkWorkerArray() {
471		ForkJoinWorkerThread[] ws = workers;
#	Line 460 | Line 481 | public class ForkJoinPool extends Abstra
481		}
482
483		/**
484	<	* Initialize workers if necessary
484	>	* Initializes workers if necessary.
485		*/
486		final void ensureWorkerInitialization() {
487		ForkJoinWorkerThread[] ws = workers;
#	Line 527 | Line 548 | public class ForkJoinPool extends Abstra
548		* Common code for execute, invoke and submit
549		*/
550		private <T> void doSubmit(ForkJoinTask<T> task) {
551	+	if (task == null)
552	+	throw new NullPointerException();
553		if (isShutdown())
554		throw new RejectedExecutionException();
555		if (workers == null)
#	Line 536 | Line 559 | public class ForkJoinPool extends Abstra
559		}
560
561		/**
562	<	* Performs the given task; returning its result upon completion
562	>	* Performs the given task, returning its result upon completion.
563	>	*
564		* @param task the task
565		* @return the task's result
566		* @throws NullPointerException if task is null
#	Line 549 | Line 573 | public class ForkJoinPool extends Abstra
573
574		/**
575		* Arranges for (asynchronous) execution of the given task.
576	+	*
577		* @param task the task
578		* @throws NullPointerException if task is null
579		* @throws RejectedExecutionException if pool is shut down
#	Line 560 | Line 585 | public class ForkJoinPool extends Abstra
585		// AbstractExecutorService methods
586
587		public void execute(Runnable task) {
588	<	doSubmit(new AdaptedRunnable<Void>(task, null));
588	>	ForkJoinTask<?> job;
589	>	if (task instanceof AdaptedCallable) // avoid re-wrap
590	>	job = (AdaptedCallable<?>)task;
591	>	else if (task instanceof AdaptedRunnable)
592	>	job = (AdaptedRunnable<?>)task;
593	>	else
594	>	job = new AdaptedRunnable<Void>(task, null);
595	>	doSubmit(job);
596		}
597
598		public <T> ForkJoinTask<T> submit(Callable<T> task) {
#	Line 576 | Line 608 | public class ForkJoinPool extends Abstra
608		}
609
610		public ForkJoinTask<?> submit(Runnable task) {
611	<	ForkJoinTask<Void> job = new AdaptedRunnable<Void>(task, null);
611	>	ForkJoinTask<?> job;
612	>	if (task instanceof AdaptedCallable) // avoid re-wrap
613	>	job = (AdaptedCallable<?>)task;
614	>	else if (task instanceof AdaptedRunnable)
615	>	job = (AdaptedRunnable<?>)task;
616	>	else
617	>	job = new AdaptedRunnable<Void>(task, null);
618		doSubmit(job);
619		return job;
620		}
621
622		/**
623	+	* Submits a ForkJoinTask for execution.
624	+	*
625	+	* @param task the task to submit
626	+	* @return the task
627	+	* @throws RejectedExecutionException if the task cannot be
628	+	*         scheduled for execution
629	+	* @throws NullPointerException if the task is null
630	+	*/
631	+	public <T> ForkJoinTask<T> submit(ForkJoinTask<T> task) {
632	+	doSubmit(task);
633	+	return task;
634	+	}
635	+
636	+	/**
637		* Adaptor for Runnables. This implements RunnableFuture
638	<	* to be compliant with AbstractExecutorService constraints
638	>	* to be compliant with AbstractExecutorService constraints.
639		*/
640		static final class AdaptedRunnable<T> extends ForkJoinTask<T>
641		implements RunnableFuture<T> {
#	Line 603 | Line 655 | public class ForkJoinPool extends Abstra
655		return true;
656		}
657		public void run() { invoke(); }
658	+	private static final long serialVersionUID = 5232453952276885070L;
659		}
660
661		/**
#	Line 631 | Line 684 | public class ForkJoinPool extends Abstra
684		}
685		}
686		public void run() { invoke(); }
687	+	private static final long serialVersionUID = 2838392045355241008L;
688		}
689
690		public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) {
691	<	ArrayList<ForkJoinTask<T>> ts =
691	>	ArrayList<ForkJoinTask<T>> forkJoinTasks =
692		new ArrayList<ForkJoinTask<T>>(tasks.size());
693	<	for (Callable<T> c : tasks)
694	<	ts.add(new AdaptedCallable<T>(c));
695	<	invoke(new InvokeAll<T>(ts));
696	<	return (List<Future<T>>)(List)ts;
693	>	for (Callable<T> task : tasks)
694	>	forkJoinTasks.add(new AdaptedCallable<T>(task));
695	>	invoke(new InvokeAll<T>(forkJoinTasks));
696	>
697	>	@SuppressWarnings({"unchecked", "rawtypes"})
698	>	List<Future<T>> futures = (List<Future<T>>) (List) forkJoinTasks;
699	>	return futures;
700		}
701
702		static final class InvokeAll<T> extends RecursiveAction {
703		final ArrayList<ForkJoinTask<T>> tasks;
704		InvokeAll(ArrayList<ForkJoinTask<T>> tasks) { this.tasks = tasks; }
705		public void compute() {
706	<	try { invokeAll(tasks); } catch(Exception ignore) {}
706	>	try { invokeAll(tasks); }
707	>	catch (Exception ignore) {}
708		}
709	+	private static final long serialVersionUID = -7914297376763021607L;
710		}
711
712		// Configuration and status settings and queries
713
714		/**
715	<	* Returns the factory used for constructing new workers
715	>	* Returns the factory used for constructing new workers.
716		*
717		* @return the factory used for constructing new workers
718		*/
#	Line 664 | Line 723 | public class ForkJoinPool extends Abstra
723		/**
724		* Returns the handler for internal worker threads that terminate
725		* due to unrecoverable errors encountered while executing tasks.
726	+	*
727		* @return the handler, or null if none
728		*/
729		public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() {
#	Line 689 | Line 749 | public class ForkJoinPool extends Abstra
749		* @throws SecurityException if a security manager exists and
750		*         the caller is not permitted to modify threads
751		*         because it does not hold {@link
752	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
752	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
753		*/
754		public Thread.UncaughtExceptionHandler
755		setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler h) {
#	Line 717 | Line 777 | public class ForkJoinPool extends Abstra
777
778		/**
779		* Sets the target parallelism level of this pool.
780	+	*
781		* @param parallelism the target parallelism
782		* @throws IllegalArgumentException if parallelism less than or
783		* equal to zero or greater than maximum size bounds
784		* @throws SecurityException if a security manager exists and
785		*         the caller is not permitted to modify threads
786		*         because it does not hold {@link
787	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
787	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
788		*/
789		public void setParallelism(int parallelism) {
790		checkPermission();
#	Line 770 | Line 831 | public class ForkJoinPool extends Abstra
831		/**
832		* Returns the maximum number of threads allowed to exist in the
833		* pool, even if there are insufficient unblocked running threads.
834	+	*
835		* @return the maximum
836		*/
837		public int getMaximumPoolSize() {
#	Line 781 | Line 843 | public class ForkJoinPool extends Abstra
843		* pool, even if there are insufficient unblocked running threads.
844		* Setting this value has no effect on current pool size. It
845		* controls construction of new threads.
846	+	*
847		* @throws IllegalArgumentException if negative or greater then
848		* internal implementation limit
849		*/
#	Line 795 | Line 858 | public class ForkJoinPool extends Abstra
858		* Returns true if this pool dynamically maintains its target
859		* parallelism level. If false, new threads are added only to
860		* avoid possible starvation.
861	<	* This setting is by default true;
861	>	* This setting is by default true.
862	>	*
863		* @return true if maintains parallelism
864		*/
865		public boolean getMaintainsParallelism() {
#	Line 806 | Line 870 | public class ForkJoinPool extends Abstra
870		* Sets whether this pool dynamically maintains its target
871		* parallelism level. If false, new threads are added only to
872		* avoid possible starvation.
873	+	*
874		* @param enable true to maintains parallelism
875		*/
876		public void setMaintainsParallelism(boolean enable) {
#	Line 863 | Line 928 | public class ForkJoinPool extends Abstra
928		* Returns an estimate of the number of threads that are currently
929		* stealing or executing tasks. This method may overestimate the
930		* number of active threads.
931	+	*
932		* @return the number of active threads
933		*/
934		public int getActiveThreadCount() {
#	Line 873 | Line 939 | public class ForkJoinPool extends Abstra
939		* Returns an estimate of the number of threads that are currently
940		* idle waiting for tasks. This method may underestimate the
941		* number of idle threads.
942	+	*
943		* @return the number of idle threads
944		*/
945		final int getIdleThreadCount() {
946		int c = runningCountOf(workerCounts) - activeCountOf(runControl);
947	<	return (c <= 0)? 0 : c;
947	>	return (c <= 0) ? 0 : c;
948		}
949
950		/**
951		* Returns true if all worker threads are currently idle. An idle
952		* worker is one that cannot obtain a task to execute because none
953		* are available to steal from other threads, and there are no
954	<	* pending submissions to the pool. This method is conservative:
955	<	* It might not return true immediately upon idleness of all
954	>	* pending submissions to the pool. This method is conservative;
955	>	* it might not return true immediately upon idleness of all
956		* threads, but will eventually become true if threads remain
957		* inactive.
958	+	*
959		* @return true if all threads are currently idle
960		*/
961		public boolean isQuiescent() {
#	Line 899 | Line 967 | public class ForkJoinPool extends Abstra
967		* one thread's work queue by another. The reported value
968		* underestimates the actual total number of steals when the pool
969		* is not quiescent. This value may be useful for monitoring and
970	<	* tuning fork/join programs: In general, steal counts should be
970	>	* tuning fork/join programs: in general, steal counts should be
971		* high enough to keep threads busy, but low enough to avoid
972		* overhead and contention across threads.
973	+	*
974		* @return the number of steals
975		*/
976		public long getStealCount() {
#	Line 909 | Line 978 | public class ForkJoinPool extends Abstra
978		}
979
980		/**
981	<	* Accumulate steal count from a worker. Call only
982	<	* when worker known to be idle.
981	>	* Accumulates steal count from a worker.
982	>	* Call only when worker known to be idle.
983		*/
984		private void updateStealCount(ForkJoinWorkerThread w) {
985		int sc = w.getAndClearStealCount();
#	Line 925 | Line 994 | public class ForkJoinPool extends Abstra
994		* an approximation, obtained by iterating across all threads in
995		* the pool. This method may be useful for tuning task
996		* granularities.
997	+	*
998		* @return the number of queued tasks
999		*/
1000		public long getQueuedTaskCount() {
#	Line 944 | Line 1014 | public class ForkJoinPool extends Abstra
1014		* Returns an estimate of the number tasks submitted to this pool
1015		* that have not yet begun executing. This method takes time
1016		* proportional to the number of submissions.
1017	+	*
1018		* @return the number of queued submissions
1019		*/
1020		public int getQueuedSubmissionCount() {
#	Line 953 | Line 1024 | public class ForkJoinPool extends Abstra
1024		/**
1025		* Returns true if there are any tasks submitted to this pool
1026		* that have not yet begun executing.
1027	+	*
1028		* @return {@code true} if there are any queued submissions
1029		*/
1030		public boolean hasQueuedSubmissions() {
#	Line 963 | Line 1035 | public class ForkJoinPool extends Abstra
1035		* Removes and returns the next unexecuted submission if one is
1036		* available.  This method may be useful in extensions to this
1037		* class that re-assign work in systems with multiple pools.
1038	+	*
1039		* @return the next submission, or null if none
1040		*/
1041		protected ForkJoinTask<?> pollSubmission() {
#	Line 982 | Line 1055 | public class ForkJoinPool extends Abstra
1055		* exception is thrown.  The behavior of this operation is
1056		* undefined if the specified collection is modified while the
1057		* operation is in progress.
1058	+	*
1059		* @param c the collection to transfer elements into
1060		* @return the number of elements transferred
1061		*/
#	Line 1042 | Line 1116 | public class ForkJoinPool extends Abstra
1116		* Invocation has no additional effect if already shut down.
1117		* Tasks that are in the process of being submitted concurrently
1118		* during the course of this method may or may not be rejected.
1119	+	*
1120		* @throws SecurityException if a security manager exists and
1121		*         the caller is not permitted to modify threads
1122		*         because it does not hold {@link
1123	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
1123	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
1124		*/
1125		public void shutdown() {
1126		checkPermission();
#	Line 1063 | Line 1138 | public class ForkJoinPool extends Abstra
1138		* upon termination, so always returns an empty list. However, you
1139		* can use method {@code drainTasksTo} before invoking this
1140		* method to transfer unexecuted tasks to another collection.
1141	+	*
1142		* @return an empty list
1143		* @throws SecurityException if a security manager exists and
1144		*         the caller is not permitted to modify threads
1145		*         because it does not hold {@link
1146	<	*         java.lang.RuntimePermission}{@code ("modifyThread")},
1146	>	*         java.lang.RuntimePermission}{@code ("modifyThread")}
1147		*/
1148		public List<Runnable> shutdownNow() {
1149		checkPermission();
#	Line 1135 | Line 1211 | public class ForkJoinPool extends Abstra
1211		// Shutdown and termination support
1212
1213		/**
1214	<	* Callback from terminating worker. Null out the corresponding
1215	<	* workers slot, and if terminating, try to terminate, else try to
1216	<	* shrink workers array.
1214	>	* Callback from terminating worker. Nulls out the corresponding
1215	>	* workers slot, and if terminating, tries to terminate; else
1216	>	* tries to shrink workers array.
1217	>	*
1218		* @param w the worker
1219		*/
1220		final void workerTerminated(ForkJoinWorkerThread w) {
#	Line 1168 | Line 1245 | public class ForkJoinPool extends Abstra
1245		}
1246
1247		/**
1248	<	* Initiate termination.
1248	>	* Initiates termination.
1249		*/
1250		private void terminate() {
1251		if (transitionRunStateTo(TERMINATING)) {
#	Line 1345 | Line 1422 | public class ForkJoinPool extends Abstra
1422		* Ensures that no thread is waiting for count to advance from the
1423		* current value of eventCount read on entry to this method, by
1424		* releasing waiting threads if necessary.
1425	+	*
1426		* @return the count
1427		*/
1428		final long ensureSync() {
#	Line 1366 | Line 1444 | public class ForkJoinPool extends Abstra
1444		*/
1445		private void signalIdleWorkers() {
1446		long c;
1447	<	do;while (!casEventCount(c = eventCount, c+1));
1447	>	do {} while (!casEventCount(c = eventCount, c+1));
1448		ensureSync();
1449		}
1450
#	Line 1390 | Line 1468 | public class ForkJoinPool extends Abstra
1468		* Waits until event count advances from last value held by
1469		* caller, or if excess threads, caller is resumed as spare, or
1470		* caller or pool is terminating. Updates caller's event on exit.
1471	+	*
1472		* @param w the calling worker thread
1473		*/
1474		final void sync(ForkJoinWorkerThread w) {
#	Line 1420 | Line 1499 | public class ForkJoinPool extends Abstra
1499		* Returns true if worker waiting on sync can proceed:
1500		*  - on signal (thread == null)
1501		*  - on event count advance (winning race to notify vs signaller)
1502	<	*  - on Interrupt
1502	>	*  - on interrupt
1503		*  - if the first queued node, we find work available
1504		* If node was not signalled and event count not advanced on exit,
1505		* then we also help advance event count.
1506	+	*
1507		* @return true if node can be released
1508		*/
1509		final boolean syncIsReleasable(WaitQueueNode node) {
#	Line 1464 | Line 1544 | public class ForkJoinPool extends Abstra
1544		* spare thread when one is about to block (and remove or
1545		* suspend it later when unblocked -- see suspendIfSpare).
1546		* However, implementing this idea requires coping with
1547	<	* several problems: We have imperfect information about the
1547	>	* several problems: we have imperfect information about the
1548		* states of threads. Some count updates can and usually do
1549		* lag run state changes, despite arrangements to keep them
1550		* accurate (for example, when possible, updating counts
#	Line 1487 | Line 1567 | public class ForkJoinPool extends Abstra
1567		* target counts, else create only to avoid starvation
1568		* @return true if joinMe known to be done
1569		*/
1570	<	final boolean preJoin(ForkJoinTask<?> joinMe, boolean maintainParallelism) {
1570	>	final boolean preJoin(ForkJoinTask<?> joinMe,
1571	>	boolean maintainParallelism) {
1572		maintainParallelism &= maintainsParallelism; // overrride
1573		boolean dec = false;  // true when running count decremented
1574		while (spareStack == null || !tryResumeSpare(dec)) {
1575		int counts = workerCounts;
1576	<	if (dec || (dec = casWorkerCounts(counts, --counts))) { // CAS cheat
1576	>	if (dec || (dec = casWorkerCounts(counts, --counts))) {
1577	>	// CAS cheat
1578		if (!needSpare(counts, maintainParallelism))
1579		break;
1580		if (joinMe.status < 0)
#	Line 1507 | Line 1589 | public class ForkJoinPool extends Abstra
1589		/**
1590		* Same idea as preJoin
1591		*/
1592	<	final boolean preBlock(ManagedBlocker blocker, boolean maintainParallelism){
1592	>	final boolean preBlock(ManagedBlocker blocker,
1593	>	boolean maintainParallelism) {
1594		maintainParallelism &= maintainsParallelism;
1595		boolean dec = false;
1596		while (spareStack == null || !tryResumeSpare(dec)) {
#	Line 1531 | Line 1614 | public class ForkJoinPool extends Abstra
1614		* there is apparently some work to do.  This self-limiting rule
1615		* means that the more threads that have already been added, the
1616		* less parallelism we will tolerate before adding another.
1617	+	*
1618		* @param counts current worker counts
1619		* @param maintainParallelism try to maintain parallelism
1620		*/
#	Line 1550 | Line 1634 | public class ForkJoinPool extends Abstra
1634		/**
1635		* Adds a spare worker if lock available and no more than the
1636		* expected numbers of threads exist.
1637	+	*
1638		* @return true if successful
1639		*/
1640		private boolean tryAddSpare(int expectedCounts) {
#	Line 1609 | Line 1694 | public class ForkJoinPool extends Abstra
1694		* the same WaitQueueNodes as barriers.  They are resumed mainly
1695		* in preJoin, but are also woken on pool events that require all
1696		* threads to check run state.
1697	+	*
1698		* @param w the caller
1699		*/
1700		private boolean suspendIfSpare(ForkJoinWorkerThread w) {
#	Line 1619 | Line 1705 | public class ForkJoinPool extends Abstra
1705		node = new WaitQueueNode(0, w);
1706		if (casWorkerCounts(s, s-1)) { // representation-dependent
1707		// push onto stack
1708	<	do;while (!casSpareStack(node.next = spareStack, node));
1708	>	do {} while (!casSpareStack(node.next = spareStack, node));
1709		// block until released by resumeSpare
1710		node.awaitSpareRelease();
1711		return true;
#	Line 1630 | Line 1716 | public class ForkJoinPool extends Abstra
1716
1717		/**
1718		* Tries to pop and resume a spare thread.
1719	+	*
1720		* @param updateCount if true, increment running count on success
1721		* @return true if successful
1722		*/
#	Line 1648 | Line 1735 | public class ForkJoinPool extends Abstra
1735
1736		/**
1737		* Pops and resumes all spare threads. Same idea as ensureSync.
1738	+	*
1739		* @return true if any spares released
1740		*/
1741		private boolean resumeAllSpares() {
#	Line 1691 | Line 1779 | public class ForkJoinPool extends Abstra
1779		* Interface for extending managed parallelism for tasks running
1780		* in ForkJoinPools. A ManagedBlocker provides two methods.
1781		* Method {@code isReleasable} must return true if blocking is not
1782	<	* necessary. Method {@code block} blocks the current thread
1783	<	* if necessary (perhaps internally invoking isReleasable before
1784	<	* actually blocking.).
1782	>	* necessary. Method {@code block} blocks the current thread if
1783	>	* necessary (perhaps internally invoking {@code isReleasable}
1784	>	* before actually blocking.).
1785	>	*
1786		* <p>For example, here is a ManagedBlocker based on a
1787		* ReentrantLock:
1788	<	* <pre>
1789	<	*   class ManagedLocker implements ManagedBlocker {
1790	<	*     final ReentrantLock lock;
1791	<	*     boolean hasLock = false;
1792	<	*     ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1793	<	*     public boolean block() {
1794	<	*        if (!hasLock)
1795	<	*           lock.lock();
1796	<	*        return true;
1797	<	*     }
1798	<	*     public boolean isReleasable() {
1799	<	*        return hasLock || (hasLock = lock.tryLock());
1711	<	*     }
1788	>	*  <pre> {@code
1789	>	* class ManagedLocker implements ManagedBlocker {
1790	>	*   final ReentrantLock lock;
1791	>	*   boolean hasLock = false;
1792	>	*   ManagedLocker(ReentrantLock lock) { this.lock = lock; }
1793	>	*   public boolean block() {
1794	>	*     if (!hasLock)
1795	>	*       lock.lock();
1796	>	*     return true;
1797	>	*   }
1798	>	*   public boolean isReleasable() {
1799	>	*     return hasLock || (hasLock = lock.tryLock());
1800		*   }
1801	<	* </pre>
1801	>	* }}</pre>
1802		*/
1803		public static interface ManagedBlocker {
1804		/**
1805		* Possibly blocks the current thread, for example waiting for
1806		* a lock or condition.
1807	+	*
1808		* @return true if no additional blocking is necessary (i.e.,
1809		* if isReleasable would return true)
1810		* @throws InterruptedException if interrupted while waiting
1811	<	* (the method is not required to do so, but is allowed to).
1811	>	* (the method is not required to do so, but is allowed to)
1812		*/
1813		boolean block() throws InterruptedException;
1814
#	Line 1736 | Line 1825 | public class ForkJoinPool extends Abstra
1825		* while the current thread is blocked.  If
1826		* {@code maintainParallelism} is true and the pool supports
1827		* it ({@link #getMaintainsParallelism}), this method attempts to
1828	<	* maintain the pool's nominal parallelism. Otherwise if activates
1828	>	* maintain the pool's nominal parallelism. Otherwise it activates
1829		* a thread only if necessary to avoid complete starvation. This
1830		* option may be preferable when blockages use timeouts, or are
1831		* almost always brief.
1832		*
1833		* <p> If the caller is not a ForkJoinTask, this method is behaviorally
1834		* equivalent to
1835	<	* <pre>
1836	<	*   while (!blocker.isReleasable())
1837	<	*      if (blocker.block())
1838	<	*         return;
1839	<	* </pre>
1835	>	*  <pre> {@code
1836	>	* while (!blocker.isReleasable())
1837	>	*   if (blocker.block())
1838	>	*     return;
1839	>	* }</pre>
1840		* If the caller is a ForkJoinTask, then the pool may first
1841		* be expanded to ensure parallelism, and later adjusted.
1842		*
#	Line 1762 | Line 1851 | public class ForkJoinPool extends Abstra
1851		boolean maintainParallelism)
1852		throws InterruptedException {
1853		Thread t = Thread.currentThread();
1854	<	ForkJoinPool pool = (t instanceof ForkJoinWorkerThread?
1855	<	((ForkJoinWorkerThread)t).pool : null);
1854	>	ForkJoinPool pool = ((t instanceof ForkJoinWorkerThread) ?
1855	>	((ForkJoinWorkerThread) t).pool : null);
1856		if (!blocker.isReleasable()) {
1857		try {
1858		if (pool == null ||
#	Line 1778 | Line 1867 | public class ForkJoinPool extends Abstra
1867
1868		private static void awaitBlocker(ManagedBlocker blocker)
1869		throws InterruptedException {
1870	<	do;while (!blocker.isReleasable() && !blocker.block());
1870	>	do {} while (!blocker.isReleasable() && !blocker.block());
1871		}
1872
1873		// AbstractExecutorService overrides
1874
1875		protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) {
1876	<	return new AdaptedRunnable(runnable, value);
1876	>	return new AdaptedRunnable<T>(runnable, value);
1877		}
1878
1879		protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
1880	<	return new AdaptedCallable(callable);
1880	>	return new AdaptedCallable<T>(callable);
1881		}
1882
1883
1884	<	// Temporary Unsafe mechanics for preliminary release
1885	<	private static Unsafe getUnsafe() throws Throwable {
1884	>	// Unsafe mechanics for jsr166y 3rd party package.
1885	>	private static sun.misc.Unsafe getUnsafe() {
1886		try {
1887	<	return Unsafe.getUnsafe();
1887	>	return sun.misc.Unsafe.getUnsafe();
1888		} catch (SecurityException se) {
1889		try {
1890		return java.security.AccessController.doPrivileged
1891	<	(new java.security.PrivilegedExceptionAction<Unsafe>() {
1892	<	public Unsafe run() throws Exception {
1893	<	return getUnsafePrivileged();
1891	>	(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
1892	>	public sun.misc.Unsafe run() throws Exception {
1893	>	return getUnsafeByReflection();
1894		}});
1895		} catch (java.security.PrivilegedActionException e) {
1896	<	throw e.getCause();
1896	>	throw new RuntimeException("Could not initialize intrinsics",
1897	>	e.getCause());
1898		}
1899		}
1900		}
1901
1902	<	private static Unsafe getUnsafePrivileged()
1902	>	private static sun.misc.Unsafe getUnsafeByReflection()
1903		throws NoSuchFieldException, IllegalAccessException {
1904	<	Field f = Unsafe.class.getDeclaredField("theUnsafe");
1904	>	java.lang.reflect.Field f =
1905	>	sun.misc.Unsafe.class.getDeclaredField("theUnsafe");
1906		f.setAccessible(true);
1907	<	return (Unsafe) f.get(null);
1907	>	return (sun.misc.Unsafe) f.get(null);
1908		}
1909
1910	<	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;
1827	<	static final long workerCountsOffset;
1828	<	static final long runControlOffset;
1829	<	static final long syncStackOffset;
1830	<	static final long spareStackOffset;
1831	<
1832	<	static {
1910	>	private static long fieldOffset(String fieldName, Class<?> klazz) {
1911		try {
1912	<	UNSAFE = getUnsafe();
1913	<	eventCountOffset = fieldOffset("eventCount");
1914	<	workerCountsOffset = fieldOffset("workerCounts");
1915	<	runControlOffset = fieldOffset("runControl");
1916	<	syncStackOffset = fieldOffset("syncStack");
1917	<	spareStackOffset = fieldOffset("spareStack");
1840	<	} catch (Throwable e) {
1841	<	throw new RuntimeException("Could not initialize intrinsics", e);
1912	>	return UNSAFE.objectFieldOffset(klazz.getDeclaredField(fieldName));
1913	>	} catch (NoSuchFieldException e) {
1914	>	// Convert Exception to Error
1915	>	NoSuchFieldError error = new NoSuchFieldError(fieldName);
1916	>	error.initCause(e);
1917	>	throw error;
1918		}
1919		}
1920
1921	+	private static final sun.misc.Unsafe UNSAFE = getUnsafe();
1922	+	static final long eventCountOffset =
1923	+	fieldOffset("eventCount", ForkJoinPool.class);
1924	+	static final long workerCountsOffset =
1925	+	fieldOffset("workerCounts", ForkJoinPool.class);
1926	+	static final long runControlOffset =
1927	+	fieldOffset("runControl", ForkJoinPool.class);
1928	+	static final long syncStackOffset =
1929	+	fieldOffset("syncStack",ForkJoinPool.class);
1930	+	static final long spareStackOffset =
1931	+	fieldOffset("spareStack", ForkJoinPool.class);
1932	+
1933		private boolean casEventCount(long cmp, long val) {
1934		return UNSAFE.compareAndSwapLong(this, eventCountOffset, cmp, val);
1935		}

Diff Legend

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