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root/jsr166/jsr166/src/jsr166e/ForkJoinPool.java

Comparing jsr166/src/jsr166e/ForkJoinPool.java (file contents):
Revision 1.13 by jsr166, Wed Nov 14 18:45:53 2012 UTC vs.
Revision 1.56 by jsr166, Wed Feb 13 18:30:47 2013 UTC

#	Line 17 | Line 17 | import java.util.concurrent.ExecutorServ
17		import java.util.concurrent.Future;
18		import java.util.concurrent.RejectedExecutionException;
19		import java.util.concurrent.RunnableFuture;
20	–	import java.util.concurrent.ThreadLocalRandom;
20		import java.util.concurrent.TimeUnit;
21
22		/**
#	Line 38 | Line 37 | import java.util.concurrent.TimeUnit;
37		* ForkJoinPool}s may also be appropriate for use with event-style
38		* tasks that are never joined.
39		*
40	<	* <p>A static {@link #commonPool} is available and appropriate for
40	>	* <p>A static {@link #commonPool()} is available and appropriate for
41		* most applications. The common pool is used by any ForkJoinTask that
42		* is not explicitly submitted to a specified pool. Using the common
43		* pool normally reduces resource usage (its threads are slowly
#	Line 52 | Line 51 | import java.util.concurrent.TimeUnit;
51		* dynamically adding, suspending, or resuming internal worker
52		* threads, even if some tasks are stalled waiting to join
53		* others. However, no such adjustments are guaranteed in the face of
54	<	* blocked IO or other unmanaged synchronization. The nested {@link
54	>	* blocked I/O or other unmanaged synchronization. The nested {@link
55		* ManagedBlocker} interface enables extension of the kinds of
56		* synchronization accommodated.
57		*
#	Line 63 | Line 62 | import java.util.concurrent.TimeUnit;
62		* {@link #toString} returns indications of pool state in a
63		* convenient form for informal monitoring.
64		*
65	<	* <p> As is the case with other ExecutorServices, there are three
65	>	* <p>As is the case with other ExecutorServices, there are three
66		* main task execution methods summarized in the following table.
67		* These are designed to be used primarily by clients not already
68		* engaged in fork/join computations in the current pool.  The main
#	Line 100 | Line 99 | import java.util.concurrent.TimeUnit;
99		*
100		* <p>The common pool is by default constructed with default
101		* parameters, but these may be controlled by setting three {@link
102	<	* System#getProperty properties} with prefix {@code
102	>	* System#getProperty system properties} with prefix {@code
103		* java.util.concurrent.ForkJoinPool.common}: {@code parallelism} --
104		* an integer greater than zero, {@code threadFactory} -- the class
105		* name of a {@link ForkJoinWorkerThreadFactory}, and {@code
106		* exceptionHandler} -- the class name of a {@link
107	+	* java.lang.Thread.UncaughtExceptionHandler
108		* Thread.UncaughtExceptionHandler}. Upon any error in establishing
109		* these settings, default parameters are used.
110		*
#	Line 239 | Line 239 | public class ForkJoinPool extends Abstra
239		* enable shutdown.  When used as a lock, it is normally only very
240		* briefly held, so is nearly always available after at most a
241		* brief spin, but we use a monitor-based backup strategy to
242	<	* blocking when needed.
242	>	* block when needed.
243		*
244		* Recording WorkQueues.  WorkQueues are recorded in the
245		* "workQueues" array that is created upon first use and expanded
#	Line 248 | Line 248 | public class ForkJoinPool extends Abstra
248		* by a lock but the array is otherwise concurrently readable, and
249		* accessed directly.  To simplify index-based operations, the
250		* array size is always a power of two, and all readers must
251	<	* tolerate null slots. Worker queues are at odd indices Shared
251	>	* tolerate null slots. Worker queues are at odd indices. Shared
252		* (submission) queues are at even indices, up to a maximum of 64
253		* slots, to limit growth even if array needs to expand to add
254		* more workers. Grouping them together in this way simplifies and
#	Line 316 | Line 316 | public class ForkJoinPool extends Abstra
316		* execute. However, many other threads may notice the same task
317		* and each signal to wake up a thread that might take it. So in
318		* general, pools will be over-signalled.  When a submission is
319	<	* added or another worker adds a task to a queue that is
320	<	* apparently empty, they signal waiting workers (or trigger
319	>	* added or another worker adds a task to a queue that has fewer
320	>	* than two tasks, they signal waiting workers (or trigger
321		* creation of new ones if fewer than the given parallelism level
322	<	* -- see signalWork).  These primary signals are buttressed by
323	<	* signals whenever other threads scan for work or do not have a
324	<	* task to process. On most platforms, signalling (unpark)
325	<	* overhead time is noticeably long, and the time between
326	<	* signalling a thread and it actually making progress can be very
327	<	* noticeably long, so it is worth offloading these delays from
328	<	* critical paths as much as possible.
322	>	* -- signalWork), and may leave a hint to the unparked worker to
323	>	* help signal others upon wakeup).  These primary signals are
324	>	* buttressed by others (see method helpSignal) whenever other
325	>	* threads scan for work or do not have a task to process.  On
326	>	* most platforms, signalling (unpark) overhead time is noticeably
327	>	* long, and the time between signalling a thread and it actually
328	>	* making progress can be very noticeably long, so it is worth
329	>	* offloading these delays from critical paths as much as
330	>	* possible.
331		*
332		* Trimming workers. To release resources after periods of lack of
333		* use, a worker starting to wait when the pool is quiescent will
#	Line 393 | Line 395 | public class ForkJoinPool extends Abstra
395		* steals, rather than use per-task bookkeeping.  This sometimes
396		* requires a linear scan of workQueues array to locate stealers,
397		* but often doesn't because stealers leave hints (that may become
398	<	* stale/wrong) of where to locate them.  A stealHint is only a
399	<	* hint because a worker might have had multiple steals and the
400	<	* hint records only one of them (usually the most current).
401	<	* Hinting isolates cost to when it is needed, rather than adding
402	<	* to per-task overhead.  (2) It is "shallow", ignoring nesting
403	<	* and potentially cyclic mutual steals.  (3) It is intentionally
398	>	* stale/wrong) of where to locate them.  It is only a hint
399	>	* because a worker might have had multiple steals and the hint
400	>	* records only one of them (usually the most current).  Hinting
401	>	* isolates cost to when it is needed, rather than adding to
402	>	* per-task overhead.  (2) It is "shallow", ignoring nesting and
403	>	* potentially cyclic mutual steals.  (3) It is intentionally
404		* racy: field currentJoin is updated only while actively joining,
405		* which means that we miss links in the chain during long-lived
406		* tasks, GC stalls etc (which is OK since blocking in such cases
#	Line 438 | Line 440 | public class ForkJoinPool extends Abstra
440		* Common Pool
441		* ===========
442		*
443	<	* The static commonPool always exists after static
443	>	* The static common Pool always exists after static
444		* initialization.  Since it (or any other created pool) need
445		* never be used, we minimize initial construction overhead and
446		* footprint to the setup of about a dozen fields, with no nested
#	Line 449 | Line 451 | public class ForkJoinPool extends Abstra
451		* perform some subtask processing (see externalHelpJoin and
452		* related methods).  We do not need to record whether these
453		* submissions are to the common pool -- if not, externalHelpJoin
454	<	* returns quicky (at the most helping to signal some common pool
454	>	* returns quickly (at the most helping to signal some common pool
455		* workers). These submitters would otherwise be blocked waiting
456		* for completion, so the extra effort (with liberally sprinkled
457		* task status checks) in inapplicable cases amounts to an odd
#	Line 525 | Line 527 | public class ForkJoinPool extends Abstra
527		* Default ForkJoinWorkerThreadFactory implementation; creates a
528		* new ForkJoinWorkerThread.
529		*/
530	<	static class DefaultForkJoinWorkerThreadFactory
530	>	static final class DefaultForkJoinWorkerThreadFactory
531		implements ForkJoinWorkerThreadFactory {
532	<	public ForkJoinWorkerThread newThread(ForkJoinPool pool) {
532	>	public final ForkJoinWorkerThread newThread(ForkJoinPool pool) {
533		return new ForkJoinWorkerThread(pool);
534		}
535		}
536
537		/**
538	+	* Per-thread records for threads that submit to pools. Currently
539	+	* holds only pseudo-random seed / index that is used to choose
540	+	* submission queues in method externalPush. In the future, this may
541	+	* also incorporate a means to implement different task rejection
542	+	* and resubmission policies.
543	+	*
544	+	* Seeds for submitters and workers/workQueues work in basically
545	+	* the same way but are initialized and updated using slightly
546	+	* different mechanics. Both are initialized using the same
547	+	* approach as in class ThreadLocal, where successive values are
548	+	* unlikely to collide with previous values. Seeds are then
549	+	* randomly modified upon collisions using xorshifts, which
550	+	* requires a non-zero seed.
551	+	*/
552	+	static final class Submitter {
553	+	int seed;
554	+	Submitter(int s) { seed = s; }
555	+	}
556	+
557	+	/**
558		* Class for artificial tasks that are used to replace the target
559		* of local joins if they are removed from an interior queue slot
560		* in WorkQueue.tryRemoveAndExec. We don't need the proxy to
#	Line 598 | Line 620 | public class ForkJoinPool extends Abstra
620		* trades off slightly slower average field access for the sake of
621		* avoiding really bad worst-case access. (Until better JVM
622		* support is in place, this padding is dependent on transient
623	<	* properties of JVM field layout rules.)  We also take care in
623	>	* properties of JVM field layout rules.) We also take care in
624		* allocating, sizing and resizing the array. Non-shared queue
625		* arrays are initialized by workers before use. Others are
626		* allocated on first use.
#	Line 624 | Line 646 | public class ForkJoinPool extends Abstra
646		*/
647		static final int MAXIMUM_QUEUE_CAPACITY = 1 << 26; // 64M
648
649	+	// Heuristic padding to ameliorate unfortunate memory placements
650	+	volatile long pad00, pad01, pad02, pad03, pad04, pad05, pad06;
651	+
652		int seed;                  // for random scanning; initialize nonzero
653		volatile int eventCount;   // encoded inactivation count; < 0 if inactive
654		int nextWait;              // encoded record of next event waiter
655	<	final int mode;            // lifo, fifo, or shared
631	<	int nsteals;               // cumulative number of steals
655	>	int hint;                  // steal or signal hint (index)
656		int poolIndex;             // index of this queue in pool (or 0)
657	<	int stealHint;             // index of most recent known stealer
657	>	final int mode;            // 0: lifo, > 0: fifo, < 0: shared
658	>	int nsteals;               // number of steals
659		volatile int qlock;        // 1: locked, -1: terminate; else 0
660		volatile int base;         // index of next slot for poll
661		int top;                   // index of next slot for push
#	Line 640 | Line 665 | public class ForkJoinPool extends Abstra
665		volatile Thread parker;    // == owner during call to park; else null
666		volatile ForkJoinTask<?> currentJoin;  // task being joined in awaitJoin
667		ForkJoinTask<?> currentSteal; // current non-local task being executed
643	–	// Heuristic padding to ameliorate unfortunate memory placements
644	–	Object p00, p01, p02, p03, p04, p05, p06, p07;
645	–	Object p08, p09, p0a, p0b, p0c, p0d, p0e;
668
669	<	WorkQueue(ForkJoinPool pool, ForkJoinWorkerThread owner, int mode) {
670	<	this.mode = mode;
669	>	volatile Object pad10, pad11, pad12, pad13, pad14, pad15, pad16, pad17;
670	>	volatile Object pad18, pad19, pad1a, pad1b, pad1c, pad1d;
671	>
672	>	WorkQueue(ForkJoinPool pool, ForkJoinWorkerThread owner, int mode,
673	>	int seed) {
674		this.pool = pool;
675		this.owner = owner;
676	+	this.mode = mode;
677	+	this.seed = seed;
678		// Place indices in the center of array (that is not yet allocated)
679		base = top = INITIAL_QUEUE_CAPACITY >>> 1;
680		}
681
682		/**
683	<	* Pushes a task. Call only by owner in unshared queues.
657	<	* Cases needing resizing or rejection are relyaed to fullPush
658	<	* (that also handles shared queues).
659	<	*
660	<	* @param task the task. Caller must ensure non-null.
661	<	* @throw RejectedExecutionException if array cannot be resized
683	>	* Returns the approximate number of tasks in the queue.
684		*/
685	<	final void push(ForkJoinTask<?> task) {
686	<	ForkJoinPool p; ForkJoinTask<?>[] a;
687	<	int s = top, n;
688	<	if ((a = array) != null && a.length > (n = s + 1 - base)) {
689	<	U.putOrderedObject
690	<	(a, (((a.length - 1) & s) << ASHIFT) + ABASE, task);
691	<	top = s + 1;
692	<	if (n <= 1 && (p = pool) != null)
693	<	p.signalWork(this, 1);
694	<	}
695	<	else
696	<	fullPush(task, true);
685	>	final int queueSize() {
686	>	int n = base - top;       // non-owner callers must read base first
687	>	return (n >= 0) ? 0 : -n; // ignore transient negative
688	>	}
689	>
690	>	/**
691	>	* Provides a more accurate estimate of whether this queue has
692	>	* any tasks than does queueSize, by checking whether a
693	>	* near-empty queue has at least one unclaimed task.
694	>	*/
695	>	final boolean isEmpty() {
696	>	ForkJoinTask<?>[] a; int m, s;
697	>	int n = base - (s = top);
698	>	return (n >= 0 ||
699	>	(n == -1 &&
700	>	((a = array) == null ||
701	>	(m = a.length - 1) < 0 ||
702	>	U.getObject
703	>	(a, (long)((m & (s - 1)) << ASHIFT) + ABASE) == null)));
704		}
705
706		/**
707	<	* Pushes a task if lock is free and array is either big
708	<	* enough or can be resized to be big enough. Note: a
680	<	* specialization of a common fast path of this method is in
681	<	* ForkJoinPool.externalPush. When called from a FJWT queue,
682	<	* this can fail only if the pool has been shut down or
683	<	* an out of memory error.
707	>	* Pushes a task. Call only by owner in unshared queues.  (The
708	>	* shared-queue version is embedded in method externalPush.)
709		*
710		* @param task the task. Caller must ensure non-null.
711	<	* @param owned if true, throw RJE on failure
711	>	* @throws RejectedExecutionException if array cannot be resized
712		*/
713	<	final boolean fullPush(ForkJoinTask<?> task, boolean owned) {
714	<	ForkJoinPool p; ForkJoinTask<?>[] a;
715	<	if (owned) {
716	<	if (qlock < 0) // must be shutting down
717	<	throw new RejectedExecutionException();
718	<	}
719	<	else if (!U.compareAndSwapInt(this, QLOCK, 0, 1))
720	<	return false;
721	<	try {
697	<	int s = top, oldLen, len;
698	<	if ((a = array) == null)
699	<	a = array = new ForkJoinTask<?>[len=INITIAL_QUEUE_CAPACITY];
700	<	else if ((oldLen = a.length) > s + 1 - base)
701	<	len = oldLen;
702	<	else if ((len = oldLen << 1) > MAXIMUM_QUEUE_CAPACITY)
703	<	throw new RejectedExecutionException("Capacity exceeded");
704	<	else {
705	<	int oldMask, b;
706	<	ForkJoinTask<?>[] oldA = a;
707	<	a = array = new ForkJoinTask<?>[len];
708	<	if ((oldMask = oldLen - 1) >= 0 && s - (b = base) > 0) {
709	<	int mask = len - 1;
710	<	do {
711	<	ForkJoinTask<?> x;
712	<	int oldj = ((b & oldMask) << ASHIFT) + ABASE;
713	<	int j    = ((b &    mask) << ASHIFT) + ABASE;
714	<	x = (ForkJoinTask<?>)
715	<	U.getObjectVolatile(oldA, oldj);
716	<	if (x != null &&
717	<	U.compareAndSwapObject(oldA, oldj, x, null))
718	<	U.putObjectVolatile(a, j, x);
719	<	} while (++b != s);
720	<	}
713	>	final void push(ForkJoinTask<?> task) {
714	>	ForkJoinTask<?>[] a; ForkJoinPool p;
715	>	int s = top, m, n;
716	>	if ((a = array) != null) {    // ignore if queue removed
717	>	int j = (((m = a.length - 1) & s) << ASHIFT) + ABASE;
718	>	U.putOrderedObject(a, j, task);
719	>	if ((n = (top = s + 1) - base) <= 2) {
720	>	if ((p = pool) != null)
721	>	p.signalWork(this);
722		}
723	<	U.putOrderedObject
724	<	(a, (((len - 1) & s) << ASHIFT) + ABASE, task);
724	<	top = s + 1;
725	<	} finally {
726	<	if (!owned)
727	<	qlock = 0;
723	>	else if (n >= m)
724	>	growArray();
725		}
726	<	if ((p = pool) != null)
727	<	p.signalWork(this, 1);
728	<	return true;
726	>	}
727	>
728	>	/**
729	>	* Initializes or doubles the capacity of array. Call either
730	>	* by owner or with lock held -- it is OK for base, but not
731	>	* top, to move while resizings are in progress.
732	>	*/
733	>	final ForkJoinTask<?>[] growArray() {
734	>	ForkJoinTask<?>[] oldA = array;
735	>	int size = oldA != null ? oldA.length << 1 : INITIAL_QUEUE_CAPACITY;
736	>	if (size > MAXIMUM_QUEUE_CAPACITY)
737	>	throw new RejectedExecutionException("Queue capacity exceeded");
738	>	int oldMask, t, b;
739	>	ForkJoinTask<?>[] a = array = new ForkJoinTask<?>[size];
740	>	if (oldA != null && (oldMask = oldA.length - 1) >= 0 &&
741	>	(t = top) - (b = base) > 0) {
742	>	int mask = size - 1;
743	>	do {
744	>	ForkJoinTask<?> x;
745	>	int oldj = ((b & oldMask) << ASHIFT) + ABASE;
746	>	int j    = ((b &    mask) << ASHIFT) + ABASE;
747	>	x = (ForkJoinTask<?>)U.getObjectVolatile(oldA, oldj);
748	>	if (x != null &&
749	>	U.compareAndSwapObject(oldA, oldj, x, null))
750	>	U.putObjectVolatile(a, j, x);
751	>	} while (++b != t);
752	>	}
753	>	return a;
754		}
755
756		/**
#	Line 852 | Line 874 | public class ForkJoinPool extends Abstra
874		return seed = r ^= r << 5;
875		}
876
855	–	/**
856	–	* Provides a more accurate estimate of size than (top - base)
857	–	* by ordering reads and checking whether a near-empty queue
858	–	* has at least one unclaimed task.
859	–	*/
860	–	final int queueSize() {
861	–	ForkJoinTask<?>[] a; int k, s, n;
862	–	return ((n = base - (s = top)) < 0 &&
863	–	(n != -1 ||
864	–	((a = array) != null && (k = a.length) > 0 &&
865	–	U.getObject
866	–	(a, (long)((((k - 1) & (s - 1)) << ASHIFT) + ABASE)) != null))) ?
867	–	-n : 0;
868	–	}
869	–
877		// Specialized execution methods
878
879		/**
#	Line 900 | Line 907 | public class ForkJoinPool extends Abstra
907		* or any other cancelled task. Returns (true) on any CAS
908		* or consistency check failure so caller can retry.
909		*
910	<	* @return false if no progress can be made, else true;
910	>	* @return false if no progress can be made, else true
911		*/
912		final boolean tryRemoveAndExec(ForkJoinTask<?> task) {
913		boolean stat = true, removed = false, empty = true;
#	Line 945 | Line 952 | public class ForkJoinPool extends Abstra
952
953		/**
954		* Polls for and executes the given task or any other task in
955	<	* its CountedCompleter computation
955	>	* its CountedCompleter computation.
956		*/
957		final boolean pollAndExecCC(ForkJoinTask<?> root) {
958		ForkJoinTask<?>[] a; int b; Object o;
#	Line 980 | Line 987 | public class ForkJoinPool extends Abstra
987		if (t != null) {
988		(currentSteal = t).doExec();
989		currentSteal = null;
990	<	if (++nsteals < 0) {     // spill on overflow
991	<	ForkJoinPool p;
985	<	if ((p = pool) != null)
986	<	p.collectStealCount(this);
987	<	}
988	<	if (top != base) {       // process remaining local tasks
990	>	++nsteals;
991	>	if (base - top < 0) {       // process remaining local tasks
992		if (mode == 0)
993		popAndExecAll();
994		else
#	Line 1017 | Line 1020 | public class ForkJoinPool extends Abstra
1020		s != Thread.State.TIMED_WAITING);
1021		}
1022
1020	–	/**
1021	–	* If this owned and is not already interrupted, try to
1022	–	* interrupt and/or unpark, ignoring exceptions.
1023	–	*/
1024	–	final void interruptOwner() {
1025	–	Thread wt, p;
1026	–	if ((wt = owner) != null && !wt.isInterrupted()) {
1027	–	try {
1028	–	wt.interrupt();
1029	–	} catch (SecurityException ignore) {
1030	–	}
1031	–	}
1032	–	if ((p = parker) != null)
1033	–	U.unpark(p);
1034	–	}
1035	–
1023		// Unsafe mechanics
1024		private static final sun.misc.Unsafe U;
1025		private static final long QLOCK;
1026		private static final int ABASE;
1027		private static final int ASHIFT;
1028		static {
1042	–	int s;
1029		try {
1030		U = getUnsafe();
1031		Class<?> k = WorkQueue.class;
#	Line 1047 | Line 1033 | public class ForkJoinPool extends Abstra
1033		QLOCK = U.objectFieldOffset
1034		(k.getDeclaredField("qlock"));
1035		ABASE = U.arrayBaseOffset(ak);
1036	<	s = U.arrayIndexScale(ak);
1036	>	int scale = U.arrayIndexScale(ak);
1037	>	if ((scale & (scale - 1)) != 0)
1038	>	throw new Error("data type scale not a power of two");
1039	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
1040		} catch (Exception e) {
1041		throw new Error(e);
1042		}
1054	–	if ((s & (s-1)) != 0)
1055	–	throw new Error("data type scale not a power of two");
1056	–	ASHIFT = 31 - Integer.numberOfLeadingZeros(s);
1043		}
1044		}
1045
1060	–	/**
1061	–	* Per-thread records for threads that submit to pools. Currently
1062	–	* holds only pseudo-random seed / index that is used to choose
1063	–	* submission queues in method externalPush. In the future, this may
1064	–	* also incorporate a means to implement different task rejection
1065	–	* and resubmission policies.
1066	–	*
1067	–	* Seeds for submitters and workers/workQueues work in basically
1068	–	* the same way but are initialized and updated using slightly
1069	–	* different mechanics. Both are initialized using the same
1070	–	* approach as in class ThreadLocal, where successive values are
1071	–	* unlikely to collide with previous values. Seeds are then
1072	–	* randomly modified upon collisions using xorshifts, which
1073	–	* requires a non-zero seed.
1074	–	*/
1075	–	static final class Submitter {
1076	–	int seed;
1077	–	Submitter(int s) { seed = s; }
1078	–	}
1079	–
1080	–	/** Property prefix for constructing common pool */
1081	–	private static final String propPrefix =
1082	–	"java.util.concurrent.ForkJoinPool.common.";
1083	–
1046		// static fields (initialized in static initializer below)
1047
1048		/**
#	Line 1091 | Line 1053 | public class ForkJoinPool extends Abstra
1053		defaultForkJoinWorkerThreadFactory;
1054
1055		/**
1056	<	* Common (static) pool. Non-null for public use unless a static
1057	<	* construction exception, but internal usages null-check on use
1058	<	* to paranoically avoid potential initialization circularities
1059	<	* as well as to simplify generated code.
1056	>	* Per-thread submission bookkeeping. Shared across all pools
1057	>	* to reduce ThreadLocal pollution and because random motion
1058	>	* to avoid contention in one pool is likely to hold for others.
1059	>	* Lazily initialized on first submission (but null-checked
1060	>	* in other contexts to avoid unnecessary initialization).
1061		*/
1062	<	static final ForkJoinPool commonPool;
1062	>	static final ThreadLocal<Submitter> submitters;
1063
1064		/**
1065		* Permission required for callers of methods that may start or
#	Line 1105 | Line 1068 | public class ForkJoinPool extends Abstra
1068		private static final RuntimePermission modifyThreadPermission;
1069
1070		/**
1071	<	* Per-thread submission bookkeeping. Shared across all pools
1072	<	* to reduce ThreadLocal pollution and because random motion
1073	<	* to avoid contention in one pool is likely to hold for others.
1074	<	* Lazily initialized on first submission (but null-checked
1112	<	* in other contexts to avoid unnecessary initialization).
1071	>	* Common (static) pool. Non-null for public use unless a static
1072	>	* construction exception, but internal usages null-check on use
1073	>	* to paranoically avoid potential initialization circularities
1074	>	* as well as to simplify generated code.
1075		*/
1076	<	static final ThreadLocal<Submitter> submitters;
1076	>	static final ForkJoinPool common;
1077
1078		/**
1079	<	* Common pool parallelism. Must equal commonPool.parallelism.
1079	>	* Common pool parallelism. Must equal common.parallelism.
1080		*/
1081	<	static final int commonPoolParallelism;
1081	>	static final int commonParallelism;
1082
1083		/**
1084		* Sequence number for creating workerNamePrefix.
#	Line 1124 | Line 1086 | public class ForkJoinPool extends Abstra
1086		private static int poolNumberSequence;
1087
1088		/**
1089	<	* Return the next sequence number. We don't expect this to
1090	<	* ever contend so use simple builtin sync.
1089	>	* Returns the next sequence number. We don't expect this to
1090	>	* ever contend, so use simple builtin sync.
1091		*/
1092		private static final synchronized int nextPoolId() {
1093		return ++poolNumberSequence;
#	Line 1149 | Line 1111 | public class ForkJoinPool extends Abstra
1111		private static final long FAST_IDLE_TIMEOUT =  200L * 1000L * 1000L;
1112
1113		/**
1114	+	* Tolerance for idle timeouts, to cope with timer undershoots
1115	+	*/
1116	+	private static final long TIMEOUT_SLOP = 2000000L;
1117	+
1118	+	/**
1119		* The maximum stolen->joining link depth allowed in method
1120		* tryHelpStealer.  Must be a power of two.  Depths for legitimate
1121		* chains are unbounded, but we use a fixed constant to avoid
#	Line 1248 | Line 1215 | public class ForkJoinPool extends Abstra
1215		static final int FIFO_QUEUE          =  1;
1216		static final int SHARED_QUEUE        = -1;
1217
1218	+	// bounds for #steps in scan loop -- must be power 2 minus 1
1219	+	private static final int MIN_SCAN    = 0x1ff;   // cover estimation slop
1220	+	private static final int MAX_SCAN    = 0x1ffff; // 4 * max workers
1221	+
1222		// Instance fields
1223
1224		/*
1225	<	* Field layout order in this class tends to matter more than one
1226	<	* would like. Runtime layout order is only loosely related to
1225	>	* Field layout of this class tends to matter more than one would
1226	>	* like. Runtime layout order is only loosely related to
1227		* declaration order and may differ across JVMs, but the following
1228		* empirically works OK on current JVMs.
1229		*/
1230	+
1231	+	// Heuristic padding to ameliorate unfortunate memory placements
1232	+	volatile long pad00, pad01, pad02, pad03, pad04, pad05, pad06;
1233	+
1234		volatile long stealCount;                  // collects worker counts
1235		volatile long ctl;                         // main pool control
1261	–	final int parallelism;                     // parallelism level
1262	–	final int localMode;                       // per-worker scheduling mode
1263	–	volatile int indexSeed;                    // worker/submitter index seed
1236		volatile int plock;                        // shutdown status and seqLock
1237	+	volatile int indexSeed;                    // worker/submitter index seed
1238	+	final int config;                          // mode and parallelism level
1239		WorkQueue[] workQueues;                    // main registry
1240	<	final ForkJoinWorkerThreadFactory factory; // factory for new workers
1240	>	final ForkJoinWorkerThreadFactory factory;
1241		final Thread.UncaughtExceptionHandler ueh; // per-worker UEH
1242		final String workerNamePrefix;             // to create worker name string
1243
1244	<	/*
1244	>	volatile Object pad10, pad11, pad12, pad13, pad14, pad15, pad16, pad17;
1245	>	volatile Object pad18, pad19, pad1a, pad1b;
1246	>
1247	>	/**
1248		* Acquires the plock lock to protect worker array and related
1249		* updates. This method is called only if an initial CAS on plock
1250	<	* fails. This acts as a spinLock for normal cases, but falls back
1250	>	* fails. This acts as a spinlock for normal cases, but falls back
1251		* to builtin monitor to block when (rarely) needed. This would be
1252		* a terrible idea for a highly contended lock, but works fine as
1253	<	* a more conservative alternative to a pure spinlock.  See
1277	<	* internal ConcurrentHashMap documentation for further
1278	<	* explanation of nearly the same construction.
1253	>	* a more conservative alternative to a pure spinlock.
1254		*/
1255		private int acquirePlock() {
1256		int spins = PL_SPINS, r = 0, ps, nps;
#	Line 1283 | Line 1258 | public class ForkJoinPool extends Abstra
1258		if (((ps = plock) & PL_LOCK) == 0 &&
1259		U.compareAndSwapInt(this, PLOCK, ps, nps = ps + PL_LOCK))
1260		return nps;
1261	<	else if (r == 0)
1262	<	r = ThreadLocalRandom.current().nextInt(); // randomize spins
1261	>	else if (r == 0) { // randomize spins if possible
1262	>	Thread t = Thread.currentThread(); WorkQueue w; Submitter z;
1263	>	if ((t instanceof ForkJoinWorkerThread) &&
1264	>	(w = ((ForkJoinWorkerThread)t).workQueue) != null)
1265	>	r = w.seed;
1266	>	else if ((z = submitters.get()) != null)
1267	>	r = z.seed;
1268	>	else
1269	>	r = 1;
1270	>	}
1271		else if (spins >= 0) {
1272		r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
1273		if (r >= 0)
#	Line 1318 | Line 1301 | public class ForkJoinPool extends Abstra
1301		synchronized (this) { notifyAll(); }
1302		}
1303
1304	+	/**
1305	+	* Tries to create and start one worker if fewer than target
1306	+	* parallelism level exist. Adjusts counts etc on failure.
1307	+	*/
1308	+	private void tryAddWorker() {
1309	+	long c; int u;
1310	+	while ((u = (int)((c = ctl) >>> 32)) < 0 &&
1311	+	(u & SHORT_SIGN) != 0 && (int)c == 0) {
1312	+	long nc = (long)(((u + UTC_UNIT) & UTC_MASK) |
1313	+	((u + UAC_UNIT) & UAC_MASK)) << 32;
1314	+	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1315	+	ForkJoinWorkerThreadFactory fac;
1316	+	Throwable ex = null;
1317	+	ForkJoinWorkerThread wt = null;
1318	+	try {
1319	+	if ((fac = factory) != null &&
1320	+	(wt = fac.newThread(this)) != null) {
1321	+	wt.start();
1322	+	break;
1323	+	}
1324	+	} catch (Throwable e) {
1325	+	ex = e;
1326	+	}
1327	+	deregisterWorker(wt, ex);
1328	+	break;
1329	+	}
1330	+	}
1331	+	}
1332	+
1333		//  Registering and deregistering workers
1334
1335		/**
1336	<	* Callback from ForkJoinWorkerThread constructor to establish its
1337	<	* poolIndex and record its WorkQueue. To avoid scanning bias due
1338	<	* to packing entries in front of the workQueues array, we treat
1339	<	* the array as a simple power-of-two hash table using per-thread
1340	<	* seed as hash, expanding as needed.
1341	<	*
1342	<	* @param w the worker's queue
1343	<	*/
1344	<	final void registerWorker(WorkQueue w) {
1345	<	int s, ps; // generate a rarely colliding candidate index seed
1346	<	do {} while (!U.compareAndSwapInt(this, INDEXSEED,
1347	<	s = indexSeed, s += SEED_INCREMENT) ||
1336	>	* Callback from ForkJoinWorkerThread to establish and record its
1337	>	* WorkQueue. To avoid scanning bias due to packing entries in
1338	>	* front of the workQueues array, we treat the array as a simple
1339	>	* power-of-two hash table using per-thread seed as hash,
1340	>	* expanding as needed.
1341	>	*
1342	>	* @param wt the worker thread
1343	>	* @return the worker's queue
1344	>	*/
1345	>	final WorkQueue registerWorker(ForkJoinWorkerThread wt) {
1346	>	Thread.UncaughtExceptionHandler handler; WorkQueue[] ws; int s, ps;
1347	>	wt.setDaemon(true);
1348	>	if ((handler = ueh) != null)
1349	>	wt.setUncaughtExceptionHandler(handler);
1350	>	do {} while (!U.compareAndSwapInt(this, INDEXSEED, s = indexSeed,
1351	>	s += SEED_INCREMENT) ||
1352		s == 0); // skip 0
1353	+	WorkQueue w = new WorkQueue(this, wt, config >>> 16, s);
1354		if (((ps = plock) & PL_LOCK) != 0 ||
1355		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1356		ps = acquirePlock();
1357		int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1358		try {
1359	<	WorkQueue[] ws;
1343	<	if (w != null && (ws = workQueues) != null) {
1344	<	w.seed = s;
1359	>	if ((ws = workQueues) != null) {    // skip if shutting down
1360		int n = ws.length, m = n - 1;
1361	<	int r = (s << 1) | 1;               // use odd-numbered indices
1362	<	if (ws[r &= m] != null) {           // collision
1363	<	int probes = 0;                 // step by approx half size
1361	>	int r = (s << 1) | 1;           // use odd-numbered indices
1362	>	if (ws[r &= m] != null) {       // collision
1363	>	int probes = 0;             // step by approx half size
1364		int step = (n <= 4) ? 2 : ((n >>> 1) & EVENMASK) + 2;
1365		while (ws[r = (r + step) & m] != null) {
1366		if (++probes >= n) {
#	Line 1355 | Line 1370 | public class ForkJoinPool extends Abstra
1370		}
1371		}
1372		}
1373	<	w.eventCount = w.poolIndex = r;     // establish before recording
1373	>	w.eventCount = w.poolIndex = r; // volatile write orders
1374		ws[r] = w;
1375		}
1376		} finally {
1377		if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1378		releasePlock(nps);
1379		}
1380	+	wt.setName(workerNamePrefix.concat(Integer.toString(w.poolIndex)));
1381	+	return w;
1382		}
1383
1384		/**
#	Line 1377 | Line 1394 | public class ForkJoinPool extends Abstra
1394		WorkQueue w = null;
1395		if (wt != null && (w = wt.workQueue) != null) {
1396		int ps;
1380	–	collectStealCount(w);
1397		w.qlock = -1;                // ensure set
1398	+	long ns = w.nsteals, sc;     // collect steal count
1399	+	do {} while (!U.compareAndSwapLong(this, STEALCOUNT,
1400	+	sc = stealCount, sc + ns));
1401		if (((ps = plock) & PL_LOCK) != 0 ||
1402		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1403		ps = acquirePlock();
#	Line 1394 | Line 1413 | public class ForkJoinPool extends Abstra
1413		}
1414		}
1415
1416	<	long c;                             // adjust ctl counts
1416	>	long c;                          // adjust ctl counts
1417		do {} while (!U.compareAndSwapLong
1418		(this, CTL, c = ctl, (((c - AC_UNIT) & AC_MASK) |
1419		((c - TC_UNIT) & TC_MASK) |
1420		(c & ~(AC_MASK|TC_MASK)))));
1421
1422	<	if (!tryTerminate(false, false) && w != null) {
1423	<	w.cancelAll();                  // cancel remaining tasks
1424	<	if (w.array != null)            // suppress signal if never ran
1425	<	signalWork(null, 1);        // wake up or create replacement
1426	<	if (ex == null)                 // help clean refs on way out
1427	<	ForkJoinTask.helpExpungeStaleExceptions();
1422	>	if (!tryTerminate(false, false) && w != null && w.array != null) {
1423	>	w.cancelAll();               // cancel remaining tasks
1424	>	WorkQueue[] ws; WorkQueue v; Thread p; int u, i, e;
1425	>	while ((u = (int)((c = ctl) >>> 32)) < 0 && (e = (int)c) >= 0) {
1426	>	if (e > 0) {             // activate or create replacement
1427	>	if ((ws = workQueues) == null ||
1428	>	(i = e & SMASK) >= ws.length ||
1429	>	(v = ws[i]) == null)
1430	>	break;
1431	>	long nc = (((long)(v.nextWait & E_MASK)) |
1432	>	((long)(u + UAC_UNIT) << 32));
1433	>	if (v.eventCount != (e | INT_SIGN))
1434	>	break;
1435	>	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1436	>	v.eventCount = (e + E_SEQ) & E_MASK;
1437	>	if ((p = v.parker) != null)
1438	>	U.unpark(p);
1439	>	break;
1440	>	}
1441	>	}
1442	>	else {
1443	>	if ((short)u < 0)
1444	>	tryAddWorker();
1445	>	break;
1446	>	}
1447	>	}
1448		}
1449	<
1450	<	if (ex != null)                     // rethrow
1449	>	if (ex == null)                     // help clean refs on way out
1450	>	ForkJoinTask.helpExpungeStaleExceptions();
1451	>	else                                // rethrow
1452		ForkJoinTask.rethrow(ex);
1453		}
1454
1415	–	/**
1416	–	* Collect worker steal count into total. Called on termination
1417	–	* and upon int overflow of local count. (There is a possible race
1418	–	* in the latter case vs any caller of getStealCount, which can
1419	–	* make its results less accurate than usual.)
1420	–	*/
1421	–	final void collectStealCount(WorkQueue w) {
1422	–	if (w != null) {
1423	–	long sc;
1424	–	int ns = w.nsteals;
1425	–	w.nsteals = 0; // handle overflow
1426	–	long steals = (ns >= 0) ? ns : 1L + (long)(Integer.MAX_VALUE);
1427	–	do {} while (!U.compareAndSwapLong(this, STEALCOUNT,
1428	–	sc = stealCount, sc + steals));
1429	–	}
1430	–	}
1431	–
1455		// Submissions
1456
1457		/**
#	Line 1445 | Line 1468 | public class ForkJoinPool extends Abstra
1468		(ws = workQueues) != null && (m = (ws.length - 1)) >= 0 &&
1469		(q = ws[m & z.seed & SQMASK]) != null &&
1470		U.compareAndSwapInt(q, QLOCK, 0, 1)) { // lock
1471	<	int s = q.top, n;
1472	<	if ((a = q.array) != null && a.length > (n = s + 1 - q.base)) {
1473	<	U.putObject(a, (long)(((a.length - 1) & s) << ASHIFT) + ABASE,
1474	<	task);
1471	>	int b = q.base, s = q.top, n, an;
1472	>	if ((a = q.array) != null && (an = a.length) > (n = s + 1 - b)) {
1473	>	int j = (((an - 1) & s) << ASHIFT) + ABASE;
1474	>	U.putOrderedObject(a, j, task);
1475		q.top = s + 1;                     // push on to deque
1476		q.qlock = 0;
1477	<	if (n <= 1)
1478	<	signalWork(q, 1);
1477	>	if (n <= 2)
1478	>	signalWork(q);
1479		return;
1480		}
1481		q.qlock = 0;
#	Line 1463 | Line 1486 | public class ForkJoinPool extends Abstra
1486		/**
1487		* Full version of externalPush. This method is called, among
1488		* other times, upon the first submission of the first task to the
1489	<	* pool, so must perform secondary initialization: creating
1467	<	* workQueue array and setting plock to a valid value. It also
1489	>	* pool, so must perform secondary initialization.  It also
1490		* detects first submission by an external thread by looking up
1491		* its ThreadLocal, and creates a new shared queue if the one at
1492	<	* index if empty or contended. The lock bodies must be
1492	>	* index if empty or contended. The plock lock body must be
1493		* exception-free (so no try/finally) so we optimistically
1494	<	* allocate new queues/arrays outside the locks and throw them
1495	<	* away if (very rarely) not needed. Note that the plock seq value
1496	<	* can eventually wrap around zero, but if so harmlessly fails to
1497	<	* reinitialize.
1494	>	* allocate new queues outside the lock and throw them away if
1495	>	* (very rarely) not needed.
1496	>	*
1497	>	* Secondary initialization occurs when plock is zero, to create
1498	>	* workQueue array and set plock to a valid value.  This lock body
1499	>	* must also be exception-free. Because the plock seq value can
1500	>	* eventually wrap around zero, this method harmlessly fails to
1501	>	* reinitialize if workQueues exists, while still advancing plock.
1502		*/
1503		private void fullExternalPush(ForkJoinTask<?> task) {
1504	<	for (Submitter z = null;;) {
1505	<	WorkQueue[] ws; WorkQueue q; int ps, m, r, s;
1506	<	if ((ps = plock) < 0)
1504	>	int r = 0; // random index seed
1505	>	for (Submitter z = submitters.get();;) {
1506	>	WorkQueue[] ws; WorkQueue q; int ps, m, k;
1507	>	if (z == null) {
1508	>	if (U.compareAndSwapInt(this, INDEXSEED, r = indexSeed,
1509	>	r += SEED_INCREMENT) && r != 0)
1510	>	submitters.set(z = new Submitter(r));
1511	>	}
1512	>	else if (r == 0) {                  // move to a different index
1513	>	r = z.seed;
1514	>	r ^= r << 13;                   // same xorshift as WorkQueues
1515	>	r ^= r >>> 17;
1516	>	z.seed = r ^ (r << 5);
1517	>	}
1518	>	else if ((ps = plock) < 0)
1519		throw new RejectedExecutionException();
1520	<	else if ((ws = workQueues) == null || (m = ws.length - 1) < 0) {
1521	<	int n = parallelism - 1; n |= n >>> 1; n |= n >>> 2;
1522	<	n |= n >>> 4; n |= n >>> 8; n |= n >>> 16;
1523	<	WorkQueue[] nws = new WorkQueue[(n + 1) << 1]; // power of two
1524	<	if ((ps & PL_LOCK) != 0 ||
1520	>	else if (ps == 0 || (ws = workQueues) == null ||
1521	>	(m = ws.length - 1) < 0) { // initialize workQueues
1522	>	int p = config & SMASK;         // find power of two table size
1523	>	int n = (p > 1) ? p - 1 : 1;    // ensure at least 2 slots
1524	>	n |= n >>> 1; n |= n >>> 2;  n |= n >>> 4;
1525	>	n |= n >>> 8; n |= n >>> 16; n = (n + 1) << 1;
1526	>	WorkQueue[] nws = ((ws = workQueues) == null || ws.length == 0 ?
1527	>	new WorkQueue[n] : null);
1528	>	if (((ps = plock) & PL_LOCK) != 0 ||
1529		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1530		ps = acquirePlock();
1531	<	if ((ws = workQueues) == null)
1531	>	if (((ws = workQueues) == null || ws.length == 0) && nws != null)
1532		workQueues = nws;
1533		int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1534		if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1535		releasePlock(nps);
1536		}
1537	<	else if (z == null && (z = submitters.get()) == null) {
1538	<	if (U.compareAndSwapInt(this, INDEXSEED,
1539	<	s = indexSeed, s += SEED_INCREMENT) &&
1540	<	s != 0) // skip 0
1541	<	submitters.set(z = new Submitter(s));
1537	>	else if ((q = ws[k = r & m & SQMASK]) != null) {
1538	>	if (q.qlock == 0 && U.compareAndSwapInt(q, QLOCK, 0, 1)) {
1539	>	ForkJoinTask<?>[] a = q.array;
1540	>	int s = q.top;
1541	>	boolean submitted = false;
1542	>	try {                      // locked version of push
1543	>	if ((a != null && a.length > s + 1 - q.base) ||
1544	>	(a = q.growArray()) != null) {   // must presize
1545	>	int j = (((a.length - 1) & s) << ASHIFT) + ABASE;
1546	>	U.putOrderedObject(a, j, task);
1547	>	q.top = s + 1;
1548	>	submitted = true;
1549	>	}
1550	>	} finally {
1551	>	q.qlock = 0;  // unlock
1552	>	}
1553	>	if (submitted) {
1554	>	signalWork(q);
1555	>	return;
1556	>	}
1557	>	}
1558	>	r = 0; // move on failure
1559		}
1560	<	else {
1561	<	int k = (r = z.seed) & m & SQMASK;
1562	<	if ((q = ws[k]) == null && (ps & PL_LOCK) == 0) {
1563	<	(q = new WorkQueue(this, null, SHARED_QUEUE)).poolIndex = k;
1564	<	if (((ps = plock) & PL_LOCK) != 0 ||
1565	<	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1566	<	ps = acquirePlock();
1567	<	WorkQueue w = null;
1568	<	if ((ws = workQueues) != null && k < ws.length &&
1569	<	(w = ws[k]) == null)
1511	<	ws[k] = q;
1512	<	else
1513	<	q = w;
1514	<	int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1515	<	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1516	<	releasePlock(nps);
1517	<	}
1518	<	if (q != null && q.qlock == 0 && q.fullPush(task, false))
1519	<	return;
1520	<	r ^= r << 13;                // same xorshift as WorkQueues
1521	<	r ^= r >>> 17;
1522	<	z.seed = r ^= r << 5;        // move to a different index
1560	>	else if (((ps = plock) & PL_LOCK) == 0) { // create new queue
1561	>	q = new WorkQueue(this, null, SHARED_QUEUE, r);
1562	>	if (((ps = plock) & PL_LOCK) != 0 ||
1563	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1564	>	ps = acquirePlock();
1565	>	if ((ws = workQueues) != null && k < ws.length && ws[k] == null)
1566	>	ws[k] = q;
1567	>	int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1568	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1569	>	releasePlock(nps);
1570		}
1571	+	else
1572	+	r = 0; // try elsewhere while lock held
1573		}
1574		}
1575
#	Line 1535 | Line 1584 | public class ForkJoinPool extends Abstra
1584		}
1585
1586		/**
1587	<	* Tries to create (at most one) or activate (possibly several)
1539	<	* workers if too few are active. On contention failure, continues
1540	<	* until at least one worker is signalled or the given queue is
1541	<	* empty or all workers are active.
1587	>	* Tries to create or activate a worker if too few are active.
1588		*
1589	<	* @param q if non-null, the queue holding tasks to be signalled
1544	<	* @param signals the target number of signals.
1589	>	* @param q the (non-null) queue holding tasks to be signalled
1590		*/
1591	<	final void signalWork(WorkQueue q, int signals) {
1592	<	long c; int e, u, i; WorkQueue[] ws; WorkQueue w; Thread p;
1591	>	final void signalWork(WorkQueue q) {
1592	>	int hint = q.poolIndex;
1593	>	long c; int e, u, i, n; WorkQueue[] ws; WorkQueue w; Thread p;
1594		while ((u = (int)((c = ctl) >>> 32)) < 0) {
1595		if ((e = (int)c) > 0) {
1596		if ((ws = workQueues) != null && ws.length > (i = e & SMASK) &&
#	Line 1552 | Line 1598 | public class ForkJoinPool extends Abstra
1598		long nc = (((long)(w.nextWait & E_MASK)) |
1599		((long)(u + UAC_UNIT) << 32));
1600		if (U.compareAndSwapLong(this, CTL, c, nc)) {
1601	+	w.hint = hint;
1602		w.eventCount = (e + E_SEQ) & E_MASK;
1603		if ((p = w.parker) != null)
1604		U.unpark(p);
1605	<	if (--signals <= 0)
1559	<	break;
1605	>	break;
1606		}
1607	<	else
1562	<	signals = 1;
1563	<	if ((q != null && q.queueSize() == 0))
1607	>	if (q.top - q.base <= 0)
1608		break;
1609		}
1610		else
1611		break;
1612		}
1613	<	else if (e == 0 && (u & SHORT_SIGN) != 0) {
1614	<	long nc = (long)(((u + UTC_UNIT) & UTC_MASK) |
1615	<	((u + UAC_UNIT) & UAC_MASK)) << 32;
1572	<	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1573	<	ForkJoinWorkerThread wt = null;
1574	<	Throwable ex = null;
1575	<	boolean started = false;
1576	<	try {
1577	<	ForkJoinWorkerThreadFactory fac;
1578	<	if ((fac = factory) != null &&
1579	<	(wt = fac.newThread(this)) != null) {
1580	<	wt.start();
1581	<	started = true;
1582	<	}
1583	<	} catch (Throwable rex) {
1584	<	ex = rex;
1585	<	}
1586	<	if (!started)
1587	<	deregisterWorker(wt, ex); // adjust counts on failure
1588	<	break;
1589	<	}
1590	<	}
1591	<	else
1613	>	else {
1614	>	if ((short)u < 0)
1615	>	tryAddWorker();
1616		break;
1617	+	}
1618		}
1619		}
1620
#	Line 1599 | Line 1624 | public class ForkJoinPool extends Abstra
1624		* Top-level runloop for workers, called by ForkJoinWorkerThread.run.
1625		*/
1626		final void runWorker(WorkQueue w) {
1627	<	// initialize queue array in this thread
1603	<	w.array = new ForkJoinTask<?>[WorkQueue.INITIAL_QUEUE_CAPACITY];
1627	>	w.growArray(); // allocate queue
1628		do { w.runTask(scan(w)); } while (w.qlock >= 0);
1629		}
1630
#	Line 1612 | Line 1636 | public class ForkJoinPool extends Abstra
1636		* contention, or state changes that indicate possible success on
1637		* re-invocation.
1638		*
1639	<	* The scan searches for tasks across a random permutation of
1640	<	* queues (starting at a random index and stepping by a random
1641	<	* relative prime, checking each at least once).  The scan
1642	<	* terminates upon either finding a non-empty queue, or completing
1643	<	* the sweep. If the worker is not inactivated, it takes and
1644	<	* returns a task from this queue. Otherwise, if not activated, it
1645	<	* signals workers (that may include itself) and returns so caller
1646	<	* can retry. Also returns for trtry if the worker array may have
1647	<	* changed during an empty scan.  On failure to find a task, we
1648	<	* take one of the following actions, after which the caller will
1649	<	* retry calling this method unless terminated.
1639	>	* The scan searches for tasks across queues (starting at a random
1640	>	* index, and relying on registerWorker to irregularly scatter
1641	>	* them within array to avoid bias), checking each at least twice.
1642	>	* The scan terminates upon either finding a non-empty queue, or
1643	>	* completing the sweep. If the worker is not inactivated, it
1644	>	* takes and returns a task from this queue. Otherwise, if not
1645	>	* activated, it signals workers (that may include itself) and
1646	>	* returns so caller can retry. Also returns for true if the
1647	>	* worker array may have changed during an empty scan.  On failure
1648	>	* to find a task, we take one of the following actions, after
1649	>	* which the caller will retry calling this method unless
1650	>	* terminated.
1651		*
1652		* * If pool is terminating, terminate the worker.
1653		*
1654		* * If not already enqueued, try to inactivate and enqueue the
1655		* worker on wait queue. Or, if inactivating has caused the pool
1656	<	* to be quiescent, relay to idleAwaitWork to check for
1657	<	* termination and possibly shrink pool.
1656	>	* to be quiescent, relay to idleAwaitWork to possibly shrink
1657	>	* pool.
1658		*
1659		* * If already enqueued and none of the above apply, possibly
1660	<	* (with 1/2 probablility) park awaiting signal, else lingering to
1661	<	* help scan and signal.
1660	>	* park awaiting signal, else lingering to help scan and signal.
1661	>	*
1662	>	* * If a non-empty queue discovered or left as a hint,
1663	>	* help wake up other workers before return.
1664		*
1665		* @param w the worker (via its WorkQueue)
1666		* @return a task or null if none found
1667		*/
1668		private final ForkJoinTask<?> scan(WorkQueue w) {
1669	<	WorkQueue[] ws; WorkQueue q;           // first update random seed
1670	<	int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
1671	<	int ps = plock, m;                     // volatile read order matters
1672	<	if ((ws = workQueues) != null && (m = ws.length - 1) > 0) {
1673	<	int ec = w.eventCount;             // ec is negative if inactive
1674	<	int step = (r >>> 16) | 1;         // relatively prime
1675	<	for (int j = (m + 1) << 2;  ; --j, r += step) {
1676	<	ForkJoinTask<?> t; ForkJoinTask<?>[] a; int b, n;
1677	<	if ((q = ws[r & m]) != null && (b = q.base) - q.top < 0 &&
1678	<	(a = q.array) != null) {   // probably nonempty
1669	>	WorkQueue[] ws; int m;
1670	>	int ps = plock;                          // read plock before ws
1671	>	if (w != null && (ws = workQueues) != null && (m = ws.length - 1) >= 0) {
1672	>	int ec = w.eventCount;               // ec is negative if inactive
1673	>	int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
1674	>	w.hint = -1;                         // update seed and clear hint
1675	>	int j = ((m + m + 1) | MIN_SCAN) & MAX_SCAN;
1676	>	do {
1677	>	WorkQueue q; ForkJoinTask<?>[] a; int b;
1678	>	if ((q = ws[(r + j) & m]) != null && (b = q.base) - q.top < 0 &&
1679	>	(a = q.array) != null) {     // probably nonempty
1680		int i = (((a.length - 1) & b) << ASHIFT) + ABASE;
1681	<	t = (ForkJoinTask<?>)U.getObjectVolatile(a, i);
1681	>	ForkJoinTask<?> t = (ForkJoinTask<?>)
1682	>	U.getObjectVolatile(a, i);
1683		if (q.base == b && ec >= 0 && t != null &&
1684		U.compareAndSwapObject(a, i, t, null)) {
1685	<	if ((n = q.top - (q.base = b + 1)) > 0)
1686	<	signalWork(q, n);
1687	<	return t;              // taken
1688	<	}
1689	<	if (j < m || (ec < 0 && (ec = w.eventCount) < 0)) {
1690	<	if ((n = q.queueSize() - 1) > 0)
1691	<	signalWork(q, n);
1692	<	break;                 // let caller retry after signal
1693	<	}
1694	<	}
1695	<	else if (j < 0) {              // end of scan
1696	<	long c = ctl; int e;
1697	<	if (plock != ps)           // incomplete sweep
1698	<	break;
1699	<	if ((e = (int)c) < 0)      // pool is terminating
1700	<	w.qlock = -1;
1701	<	else if (ec >= 0) {        // try to enqueue/inactivate
1702	<	long nc = ((long)ec |
1703	<	((c - AC_UNIT) & (AC_MASK|TC_MASK)));
1704	<	w.nextWait = e;
1705	<	w.eventCount = ec | INT_SIGN; // mark as inactive
1706	<	if (ctl != c ||
1707	<	!U.compareAndSwapLong(this, CTL, c, nc))
1708	<	w.eventCount = ec; // unmark on CAS failure
1709	<	else if ((int)(c >> AC_SHIFT) == 1 - parallelism)
1710	<	idleAwaitWork(w, nc, c);  // quiescent
1685	>	if ((q.base = b + 1) - q.top < 0)
1686	>	signalWork(q);
1687	>	return t;                // taken
1688	>	}
1689	>	else if ((ec < 0 || j < m) && (int)(ctl >> AC_SHIFT) <= 0) {
1690	>	w.hint = (r + j) & m;    // help signal below
1691	>	break;                   // cannot take
1692	>	}
1693	>	}
1694	>	} while (--j >= 0);
1695	>
1696	>	int h, e, ns; long c, sc; WorkQueue q;
1697	>	if ((ns = w.nsteals) != 0) {
1698	>	if (U.compareAndSwapLong(this, STEALCOUNT,
1699	>	sc = stealCount, sc + ns))
1700	>	w.nsteals = 0;               // collect steals and rescan
1701	>	}
1702	>	else if (plock != ps)                // consistency check
1703	>	;                                // skip
1704	>	else if ((e = (int)(c = ctl)) < 0)
1705	>	w.qlock = -1;                    // pool is terminating
1706	>	else {
1707	>	if ((h = w.hint) < 0) {
1708	>	if (ec >= 0) {               // try to enqueue/inactivate
1709	>	long nc = (((long)ec |
1710	>	((c - AC_UNIT) & (AC_MASK|TC_MASK))));
1711	>	w.nextWait = e;          // link and mark inactive
1712	>	w.eventCount = ec | INT_SIGN;
1713	>	if (ctl != c || !U.compareAndSwapLong(this, CTL, c, nc))
1714	>	w.eventCount = ec;   // unmark on CAS failure
1715	>	else if ((int)(c >> AC_SHIFT) == 1 - (config & SMASK))
1716	>	idleAwaitWork(w, nc, c);
1717		}
1718	<	else if (w.seed >= 0 && w.eventCount < 0) {
1718	>	else if (w.eventCount < 0 && ctl == c) {
1719		Thread wt = Thread.currentThread();
1720	<	Thread.interrupted();  // clear status
1720	>	Thread.interrupted();    // clear status
1721		U.putObject(wt, PARKBLOCKER, this);
1722	<	w.parker = wt;         // emulate LockSupport.park
1723	<	if (w.eventCount < 0)  // recheck
1724	<	U.park(false, 0L);
1722	>	w.parker = wt;           // emulate LockSupport.park
1723	>	if (w.eventCount < 0)    // recheck
1724	>	U.park(false, 0L);   // block
1725		w.parker = null;
1726		U.putObject(wt, PARKBLOCKER, null);
1727		}
1728	<	break;
1728	>	}
1729	>	if ((h >= 0 || (h = w.hint) >= 0) &&
1730	>	(ws = workQueues) != null && h < ws.length &&
1731	>	(q = ws[h]) != null) {      // signal others before retry
1732	>	WorkQueue v; Thread p; int u, i, s;
1733	>	for (int n = (config & SMASK) - 1;;) {
1734	>	int idleCount = (w.eventCount < 0) ? 0 : -1;
1735	>	if (((s = idleCount - q.base + q.top) <= n &&
1736	>	(n = s) <= 0) ||
1737	>	(u = (int)((c = ctl) >>> 32)) >= 0 ||
1738	>	(e = (int)c) <= 0 || m < (i = e & SMASK) ||
1739	>	(v = ws[i]) == null)
1740	>	break;
1741	>	long nc = (((long)(v.nextWait & E_MASK)) |
1742	>	((long)(u + UAC_UNIT) << 32));
1743	>	if (v.eventCount != (e | INT_SIGN) ||
1744	>	!U.compareAndSwapLong(this, CTL, c, nc))
1745	>	break;
1746	>	v.hint = h;
1747	>	v.eventCount = (e + E_SEQ) & E_MASK;
1748	>	if ((p = v.parker) != null)
1749	>	U.unpark(p);
1750	>	if (--n <= 0)
1751	>	break;
1752	>	}
1753		}
1754		}
1755		}
#	Line 1710 | Line 1769 | public class ForkJoinPool extends Abstra
1769		* @param prevCtl the ctl value to restore if thread is terminated
1770		*/
1771		private void idleAwaitWork(WorkQueue w, long currentCtl, long prevCtl) {
1772	<	if (w.eventCount < 0 &&
1773	<	(this == commonPool || !tryTerminate(false, false)) &&
1774	<	(int)prevCtl != 0) {
1772	>	if (w != null && w.eventCount < 0 &&
1773	>	!tryTerminate(false, false) && (int)prevCtl != 0 &&
1774	>	ctl == currentCtl) {
1775		int dc = -(short)(currentCtl >>> TC_SHIFT);
1776		long parkTime = dc < 0 ? FAST_IDLE_TIMEOUT: (dc + 1) * IDLE_TIMEOUT;
1777	<	long deadline = System.nanoTime() + parkTime - 100000L; // 1ms slop
1777	>	long deadline = System.nanoTime() + parkTime - TIMEOUT_SLOP;
1778		Thread wt = Thread.currentThread();
1779		while (ctl == currentCtl) {
1780		Thread.interrupted();  // timed variant of version in scan()
#	Line 1730 | Line 1789 | public class ForkJoinPool extends Abstra
1789		if (deadline - System.nanoTime() <= 0L &&
1790		U.compareAndSwapLong(this, CTL, currentCtl, prevCtl)) {
1791		w.eventCount = (w.eventCount + E_SEQ) | E_MASK;
1792	+	w.hint = -1;
1793		w.qlock = -1;   // shrink
1794		break;
1795		}
#	Line 1738 | Line 1798 | public class ForkJoinPool extends Abstra
1798		}
1799
1800		/**
1801	<	* Scans through queues looking for work while joining a task;
1802	<	* if any are present, signals.
1801	>	* Scans through queues looking for work while joining a task; if
1802	>	* any present, signals. May return early if more signalling is
1803	>	* detectably unneeded.
1804		*
1805	<	* @param task to return early if done
1805	>	* @param task return early if done
1806		* @param origin an index to start scan
1807		*/
1808	<	final int helpSignal(ForkJoinTask<?> task, int origin) {
1809	<	WorkQueue[] ws; WorkQueue q; int m, n, s;
1810	<	if (task != null && (ws = workQueues) != null &&
1811	<	(m = ws.length - 1) >= 0) {
1812	<	for (int i = 0; i <= m; ++i) {
1813	<	if ((s = task.status) < 0)
1814	<	return s;
1815	<	if ((q = ws[(i + origin) & m]) != null &&
1816	<	(n = q.queueSize()) > 0) {
1817	<	signalWork(q, n);
1818	<	if ((int)(ctl >> AC_SHIFT) >= 0)
1808	>	private void helpSignal(ForkJoinTask<?> task, int origin) {
1809	>	WorkQueue[] ws; WorkQueue w; Thread p; long c; int m, u, e, i, s;
1810	>	if (task != null && task.status >= 0 &&
1811	>	(u = (int)(ctl >>> 32)) < 0 && (u >> UAC_SHIFT) < 0 &&
1812	>	(ws = workQueues) != null && (m = ws.length - 1) >= 0) {
1813	>	outer: for (int k = origin, j = m; j >= 0; --j) {
1814	>	WorkQueue q = ws[k++ & m];
1815	>	for (int n = m;;) { // limit to at most m signals
1816	>	if (task.status < 0)
1817	>	break outer;
1818	>	if (q == null ||
1819	>	((s = -q.base + q.top) <= n && (n = s) <= 0))
1820		break;
1821	+	if ((u = (int)((c = ctl) >>> 32)) >= 0 ||
1822	+	(e = (int)c) <= 0 || m < (i = e & SMASK) ||
1823	+	(w = ws[i]) == null)
1824	+	break outer;
1825	+	long nc = (((long)(w.nextWait & E_MASK)) |
1826	+	((long)(u + UAC_UNIT) << 32));
1827	+	if (w.eventCount != (e | INT_SIGN))
1828	+	break outer;
1829	+	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1830	+	w.eventCount = (e + E_SEQ) & E_MASK;
1831	+	if ((p = w.parker) != null)
1832	+	U.unpark(p);
1833	+	if (--n <= 0)
1834	+	break;
1835	+	}
1836		}
1837		}
1838		}
1762	–	return 0;
1839		}
1840
1841		/**
#	Line 1793 | Line 1869 | public class ForkJoinPool extends Abstra
1869		}
1870		if ((ws = workQueues) == null || (m = ws.length - 1) <= 0)
1871		break restart;              // shutting down
1872	<	if ((v = ws[h = (j.stealHint | 1) & m]) == null ||
1872	>	if ((v = ws[h = (j.hint | 1) & m]) == null ||
1873		v.currentSteal != subtask) {
1874		for (int origin = h;;) {    // find stealer
1875		if (((h = (h + 2) & m) & 15) == 1 &&
#	Line 1801 | Line 1877 | public class ForkJoinPool extends Abstra
1877		continue restart;   // occasional staleness check
1878		if ((v = ws[h]) != null &&
1879		v.currentSteal == subtask) {
1880	<	j.stealHint = h;    // save hint
1880	>	j.hint = h;        // save hint
1881		break;
1882		}
1883		if (h == origin)
#	Line 1850 | Line 1926 | public class ForkJoinPool extends Abstra
1926
1927		/**
1928		* Analog of tryHelpStealer for CountedCompleters. Tries to steal
1929	<	* and run tasks within the target's computation
1929	>	* and run tasks within the target's computation.
1930		*
1931		* @param task the task to join
1932		* @param mode if shared, exit upon completing any task
1933		* if all workers are active
1858	–	*
1934		*/
1935		private int helpComplete(ForkJoinTask<?> task, int mode) {
1936	<	WorkQueue[] ws; WorkQueue q; int m, n, s;
1936	>	WorkQueue[] ws; WorkQueue q; int m, n, s, u;
1937		if (task != null && (ws = workQueues) != null &&
1938		(m = ws.length - 1) >= 0) {
1939		for (int j = 1, origin = j;;) {
#	Line 1866 | Line 1941 | public class ForkJoinPool extends Abstra
1941		return s;
1942		if ((q = ws[j & m]) != null && q.pollAndExecCC(task)) {
1943		origin = j;
1944	<	if (mode == SHARED_QUEUE && (int)(ctl >> AC_SHIFT) >= 0)
1944	>	if (mode == SHARED_QUEUE &&
1945	>	((u = (int)(ctl >>> 32)) >= 0 || (u >> UAC_SHIFT) >= 0))
1946		break;
1947		}
1948		else if ((j = (j + 2) & m) == origin)
#	Line 1884 | Line 1960 | public class ForkJoinPool extends Abstra
1960		* may become starved.
1961		*/
1962		final boolean tryCompensate() {
1963	<	int pc = parallelism, e, u, i, tc; long c;
1963	>	int pc = config & SMASK, e, i, tc; long c;
1964		WorkQueue[] ws; WorkQueue w; Thread p;
1965	<	if ((e = (int)(c = ctl)) >= 0 && (ws = workQueues) != null) {
1965	>	if ((ws = workQueues) != null && (e = (int)(c = ctl)) >= 0) {
1966		if (e != 0 && (i = e & SMASK) < ws.length &&
1967		(w = ws[i]) != null && w.eventCount == (e | INT_SIGN)) {
1968		long nc = ((long)(w.nextWait & E_MASK) |
#	Line 1898 | Line 1974 | public class ForkJoinPool extends Abstra
1974		return true;   // replace with idle worker
1975		}
1976		}
1977	<	else if ((short)((u = (int)(c >>> 32)) >>> UTC_SHIFT) >= 0 &&
1978	<	(u >> UAC_SHIFT) + pc > 1) {
1977	>	else if ((tc = (short)(c >>> TC_SHIFT)) >= 0 &&
1978	>	(int)(c >> AC_SHIFT) + pc > 1) {
1979		long nc = ((c - AC_UNIT) & AC_MASK) | (c & ~AC_MASK);
1980		if (U.compareAndSwapLong(this, CTL, c, nc))
1981	<	return true;    // no compensation
1981	>	return true;   // no compensation
1982		}
1983	<	else if ((tc = u + pc) < MAX_CAP) {
1983	>	else if (tc + pc < MAX_CAP) {
1984		long nc = ((c + TC_UNIT) & TC_MASK) | (c & ~TC_MASK);
1985		if (U.compareAndSwapLong(this, CTL, c, nc)) {
1986	+	ForkJoinWorkerThreadFactory fac;
1987		Throwable ex = null;
1988		ForkJoinWorkerThread wt = null;
1989		try {
1913	–	ForkJoinWorkerThreadFactory fac;
1990		if ((fac = factory) != null &&
1991		(wt = fac.newThread(this)) != null) {
1992		wt.start();
#	Line 1919 | Line 1995 | public class ForkJoinPool extends Abstra
1995		} catch (Throwable rex) {
1996		ex = rex;
1997		}
1998	<	deregisterWorker(wt, ex); // adjust counts etc
1998	>	deregisterWorker(wt, ex); // clean up and return false
1999		}
2000		}
2001		}
#	Line 1938 | Line 2014 | public class ForkJoinPool extends Abstra
2014		if (joiner != null && task != null && (s = task.status) >= 0) {
2015		ForkJoinTask<?> prevJoin = joiner.currentJoin;
2016		joiner.currentJoin = task;
2017	<	do {} while ((s = task.status) >= 0 &&
1942	<	joiner.queueSize() > 0 &&
2017	>	do {} while ((s = task.status) >= 0 && !joiner.isEmpty() &&
2018		joiner.tryRemoveAndExec(task)); // process local tasks
2019	<	if (s >= 0 && (s = task.status) >= 0 &&
2020	<	(s = helpSignal(task, joiner.poolIndex)) >= 0 &&
2021	<	(task instanceof CountedCompleter))
2022	<	s = helpComplete(task, LIFO_QUEUE);
2019	>	if (s >= 0 && (s = task.status) >= 0) {
2020	>	helpSignal(task, joiner.poolIndex);
2021	>	if ((s = task.status) >= 0 &&
2022	>	(task instanceof CountedCompleter))
2023	>	s = helpComplete(task, LIFO_QUEUE);
2024	>	}
2025		while (s >= 0 && (s = task.status) >= 0) {
2026	<	if ((joiner.queueSize() > 0 ||           // try helping
2026	>	if ((!joiner.isEmpty() ||           // try helping
2027		(s = tryHelpStealer(joiner, task)) == 0) &&
2028	<	(s = task.status) >= 0 && tryCompensate()) {
2029	<	if (task.trySetSignal() && (s = task.status) >= 0) {
2030	<	synchronized (task) {
2031	<	if (task.status >= 0) {
2032	<	try {                // see ForkJoinTask
2033	<	task.wait();     //  for explanation
2034	<	} catch (InterruptedException ie) {
2028	>	(s = task.status) >= 0) {
2029	>	helpSignal(task, joiner.poolIndex);
2030	>	if ((s = task.status) >= 0 && tryCompensate()) {
2031	>	if (task.trySetSignal() && (s = task.status) >= 0) {
2032	>	synchronized (task) {
2033	>	if (task.status >= 0) {
2034	>	try {                // see ForkJoinTask
2035	>	task.wait();     //  for explanation
2036	>	} catch (InterruptedException ie) {
2037	>	}
2038		}
2039	+	else
2040	+	task.notifyAll();
2041		}
1960	–	else
1961	–	task.notifyAll();
2042		}
2043	+	long c;                          // re-activate
2044	+	do {} while (!U.compareAndSwapLong
2045	+	(this, CTL, c = ctl, c + AC_UNIT));
2046		}
1964	–	long c;                          // re-activate
1965	–	do {} while (!U.compareAndSwapLong
1966	–	(this, CTL, c = ctl, c + AC_UNIT));
2047		}
2048		}
2049		joiner.currentJoin = prevJoin;
#	Line 1984 | Line 2064 | public class ForkJoinPool extends Abstra
2064		if (joiner != null && task != null && (s = task.status) >= 0) {
2065		ForkJoinTask<?> prevJoin = joiner.currentJoin;
2066		joiner.currentJoin = task;
2067	<	do {} while ((s = task.status) >= 0 &&
1988	<	joiner.queueSize() > 0 &&
2067	>	do {} while ((s = task.status) >= 0 && !joiner.isEmpty() &&
2068		joiner.tryRemoveAndExec(task));
2069	<	if (s >= 0 && (s = task.status) >= 0 &&
2070	<	(s = helpSignal(task, joiner.poolIndex)) >= 0 &&
2071	<	(task instanceof CountedCompleter))
2072	<	s = helpComplete(task, LIFO_QUEUE);
2073	<	if (s >= 0 && joiner.queueSize() == 0) {
2069	>	if (s >= 0 && (s = task.status) >= 0) {
2070	>	helpSignal(task, joiner.poolIndex);
2071	>	if ((s = task.status) >= 0 &&
2072	>	(task instanceof CountedCompleter))
2073	>	s = helpComplete(task, LIFO_QUEUE);
2074	>	}
2075	>	if (s >= 0 && joiner.isEmpty()) {
2076		do {} while (task.status >= 0 &&
2077		tryHelpStealer(joiner, task) > 0);
2078		}
#	Line 2001 | Line 2082 | public class ForkJoinPool extends Abstra
2082
2083		/**
2084		* Returns a (probably) non-empty steal queue, if one is found
2085	<	* during a random, then cyclic scan, else null.  This method must
2086	<	* be retried by caller if, by the time it tries to use the queue,
2006	<	* it is empty.
2085	>	* during a scan, else null.  This method must be retried by
2086	>	* caller if, by the time it tries to use the queue, it is empty.
2087		* @param r a (random) seed for scanning
2088		*/
2089		private WorkQueue findNonEmptyStealQueue(int r) {
2090	<	int step = (r >>> 16) | 1;
2091	<	for (WorkQueue[] ws;;) {
2092	<	int ps = plock, m;
2093	<	if ((ws = workQueues) == null || (m = ws.length - 1) < 1)
2094	<	return null;
2095	<	for (int j = (m + 1) << 2; ; r += step) {
2096	<	WorkQueue q = ws[((r << 1) | 1) & m];
2017	<	if (q != null && q.queueSize() > 0)
2018	<	return q;
2019	<	else if (--j < 0) {
2020	<	if (plock == ps)
2021	<	return null;
2022	<	break;
2090	>	for (;;) {
2091	>	int ps = plock, m; WorkQueue[] ws; WorkQueue q;
2092	>	if ((ws = workQueues) != null && (m = ws.length - 1) >= 0) {
2093	>	for (int j = (m + 1) << 2; j >= 0; --j) {
2094	>	if ((q = ws[(((r + j) << 1) | 1) & m]) != null &&
2095	>	q.base - q.top < 0)
2096	>	return q;
2097		}
2098		}
2099	+	if (plock == ps)
2100	+	return null;
2101		}
2102		}
2103
#	Line 2033 | Line 2109 | public class ForkJoinPool extends Abstra
2109		*/
2110		final void helpQuiescePool(WorkQueue w) {
2111		for (boolean active = true;;) {
2112	<	ForkJoinTask<?> localTask; // exhaust local queue
2113	<	while ((localTask = w.nextLocalTask()) != null)
2114	<	localTask.doExec();
2115	<	// Similar to loop in scan(), but ignoring submissions
2116	<	WorkQueue q = findNonEmptyStealQueue(w.nextSeed());
2117	<	if (q != null) {
2118	<	ForkJoinTask<?> t; int b;
2112	>	long c; WorkQueue q; ForkJoinTask<?> t; int b;
2113	>	while ((t = w.nextLocalTask()) != null) {
2114	>	if (w.base - w.top < 0)
2115	>	signalWork(w);
2116	>	t.doExec();
2117	>	}
2118	>	if ((q = findNonEmptyStealQueue(w.nextSeed())) != null) {
2119		if (!active) {      // re-establish active count
2044	–	long c;
2120		active = true;
2121		do {} while (!U.compareAndSwapLong
2122		(this, CTL, c = ctl, c + AC_UNIT));
2123		}
2124	<	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null)
2124	>	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null) {
2125	>	if (q.base - q.top < 0)
2126	>	signalWork(q);
2127		w.runSubtask(t);
2128	+	}
2129		}
2130	<	else {
2131	<	long c;
2132	<	if (active) {       // decrement active count without queuing
2130	>	else if (active) {       // decrement active count without queuing
2131	>	long nc = (c = ctl) - AC_UNIT;
2132	>	if ((int)(nc >> AC_SHIFT) + (config & SMASK) == 0)
2133	>	return;          // bypass decrement-then-increment
2134	>	if (U.compareAndSwapLong(this, CTL, c, nc))
2135		active = false;
2056	–	do {} while (!U.compareAndSwapLong
2057	–	(this, CTL, c = ctl, c -= AC_UNIT));
2058	–	}
2059	–	else
2060	–	c = ctl;        // re-increment on exit
2061	–	if ((int)(c >> AC_SHIFT) + parallelism == 0) {
2062	–	do {} while (!U.compareAndSwapLong
2063	–	(this, CTL, c = ctl, c + AC_UNIT));
2064	–	break;
2065	–	}
2136		}
2137	+	else if ((int)((c = ctl) >> AC_SHIFT) + (config & SMASK) == 0 &&
2138	+	U.compareAndSwapLong(this, CTL, c, c + AC_UNIT))
2139	+	return;
2140		}
2141		}
2142
#	Line 2079 | Line 2152 | public class ForkJoinPool extends Abstra
2152		return t;
2153		if ((q = findNonEmptyStealQueue(w.nextSeed())) == null)
2154		return null;
2155	<	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null)
2155	>	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null) {
2156	>	if (q.base - q.top < 0)
2157	>	signalWork(q);
2158		return t;
2159	+	}
2160		}
2161		}
2162
#	Line 2109 | Line 2185 | public class ForkJoinPool extends Abstra
2185		* producing extra tasks amortizes the uncertainty of progress and
2186		* diffusion assumptions.
2187		*
2188	<	* So, users will want to use values larger, but not much larger
2188	>	* So, users will want to use values larger (but not much larger)
2189		* than 1 to both smooth over transient shortages and hedge
2190		* against uneven progress; as traded off against the cost of
2191		* extra task overhead. We leave the user to pick a threshold
#	Line 2133 | Line 2209 | public class ForkJoinPool extends Abstra
2209		static int getSurplusQueuedTaskCount() {
2210		Thread t; ForkJoinWorkerThread wt; ForkJoinPool pool; WorkQueue q;
2211		if (((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)) {
2212	<	int b = (q = (wt = (ForkJoinWorkerThread)t).workQueue).base;
2213	<	int p = (pool = wt.pool).parallelism;
2212	>	int p = (pool = (wt = (ForkJoinWorkerThread)t).pool).config & SMASK;
2213	>	int n = (q = wt.workQueue).top - q.base;
2214		int a = (int)(pool.ctl >> AC_SHIFT) + p;
2215	<	return q.top - b - (a > (p >>>= 1) ? 0 :
2216	<	a > (p >>>= 1) ? 1 :
2217	<	a > (p >>>= 1) ? 2 :
2218	<	a > (p >>>= 1) ? 4 :
2219	<	8);
2215	>	return n - (a > (p >>>= 1) ? 0 :
2216	>	a > (p >>>= 1) ? 1 :
2217	>	a > (p >>>= 1) ? 2 :
2218	>	a > (p >>>= 1) ? 4 :
2219	>	8);
2220		}
2221		return 0;
2222		}
#	Line 2162 | Line 2238 | public class ForkJoinPool extends Abstra
2238		* @return true if now terminating or terminated
2239		*/
2240		private boolean tryTerminate(boolean now, boolean enable) {
2241	<	if (this == commonPool)                     // cannot shut down
2241	>	int ps;
2242	>	if (this == common)                    // cannot shut down
2243		return false;
2244	+	if ((ps = plock) >= 0) {                   // enable by setting plock
2245	+	if (!enable)
2246	+	return false;
2247	+	if ((ps & PL_LOCK) != 0 ||
2248	+	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
2249	+	ps = acquirePlock();
2250	+	int nps = ((ps + PL_LOCK) & ~SHUTDOWN) | SHUTDOWN;
2251	+	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
2252	+	releasePlock(nps);
2253	+	}
2254		for (long c;;) {
2255	<	if (((c = ctl) & STOP_BIT) != 0) {      // already terminating
2256	<	if ((short)(c >>> TC_SHIFT) == -parallelism) {
2255	>	if (((c = ctl) & STOP_BIT) != 0) {     // already terminating
2256	>	if ((short)(c >>> TC_SHIFT) == -(config & SMASK)) {
2257		synchronized (this) {
2258	<	notifyAll();                // signal when 0 workers
2258	>	notifyAll();               // signal when 0 workers
2259		}
2260		}
2261		return true;
2262		}
2263	<	if (plock >= 0) {                       // not yet enabled
2264	<	int ps;
2265	<	if (!enable)
2263	>	if (!now) {                            // check if idle & no tasks
2264	>	WorkQueue[] ws; WorkQueue w;
2265	>	if ((int)(c >> AC_SHIFT) != -(config & SMASK))
2266		return false;
2267	<	if (((ps = plock) & PL_LOCK) != 0 ||
2268	<	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
2269	<	ps = acquirePlock();
2270	<	int nps = SHUTDOWN;
2271	<	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
2272	<	releasePlock(nps);
2273	<	}
2274	<	if (!now) {                             // check if idle & no tasks
2275	<	if ((int)(c >> AC_SHIFT) != -parallelism ||
2276	<	hasQueuedSubmissions())
2190	<	return false;
2191	<	// Check for unqueued inactive workers. One pass suffices.
2192	<	WorkQueue[] ws = workQueues; WorkQueue w;
2193	<	if (ws != null) {
2194	<	for (int i = 1; i < ws.length; i += 2) {
2195	<	if ((w = ws[i]) != null && w.eventCount >= 0)
2196	<	return false;
2267	>	if ((ws = workQueues) != null) {
2268	>	for (int i = 0; i < ws.length; ++i) {
2269	>	if ((w = ws[i]) != null) {
2270	>	if (!w.isEmpty()) {    // signal unprocessed tasks
2271	>	signalWork(w);
2272	>	return false;
2273	>	}
2274	>	if ((i & 1) != 0 && w.eventCount >= 0)
2275	>	return false;      // unqueued inactive worker
2276	>	}
2277		}
2278		}
2279		}
2280		if (U.compareAndSwapLong(this, CTL, c, c | STOP_BIT)) {
2281		for (int pass = 0; pass < 3; ++pass) {
2282	<	WorkQueue[] ws = workQueues;
2283	<	if (ws != null) {
2204	<	WorkQueue w;
2282	>	WorkQueue[] ws; WorkQueue w; Thread wt;
2283	>	if ((ws = workQueues) != null) {
2284		int n = ws.length;
2285		for (int i = 0; i < n; ++i) {
2286		if ((w = ws[i]) != null) {
2287		w.qlock = -1;
2288		if (pass > 0) {
2289		w.cancelAll();
2290	<	if (pass > 1)
2291	<	w.interruptOwner();
2290	>	if (pass > 1 && (wt = w.owner) != null) {
2291	>	if (!wt.isInterrupted()) {
2292	>	try {
2293	>	wt.interrupt();
2294	>	} catch (Throwable ignore) {
2295	>	}
2296	>	}
2297	>	U.unpark(wt);
2298	>	}
2299		}
2300		}
2301		}
2302		// Wake up workers parked on event queue
2303		int i, e; long cc; Thread p;
2304		while ((e = (int)(cc = ctl) & E_MASK) != 0 &&
2305	<	(i = e & SMASK) < n &&
2305	>	(i = e & SMASK) < n && i >= 0 &&
2306		(w = ws[i]) != null) {
2307		long nc = ((long)(w.nextWait & E_MASK) |
2308		((cc + AC_UNIT) & AC_MASK) |
#	Line 2244 | Line 2330 | public class ForkJoinPool extends Abstra
2330		static WorkQueue commonSubmitterQueue() {
2331		ForkJoinPool p; WorkQueue[] ws; int m; Submitter z;
2332		return ((z = submitters.get()) != null &&
2333	<	(p = commonPool) != null &&
2333	>	(p = common) != null &&
2334		(ws = p.workQueues) != null &&
2335		(m = ws.length - 1) >= 0) ?
2336		ws[m & z.seed & SQMASK] : null;
#	Line 2255 | Line 2341 | public class ForkJoinPool extends Abstra
2341		*/
2342		static boolean tryExternalUnpush(ForkJoinTask<?> t) {
2343		ForkJoinPool p; WorkQueue[] ws; WorkQueue q; Submitter z;
2344	<	ForkJoinTask<?>[] a;  int m, s; long j;
2345	<	if ((z = submitters.get()) != null &&
2346	<	(p = commonPool) != null &&
2344	>	ForkJoinTask<?>[] a;  int m, s;
2345	>	if (t != null &&
2346	>	(z = submitters.get()) != null &&
2347	>	(p = common) != null &&
2348		(ws = p.workQueues) != null &&
2349		(m = ws.length - 1) >= 0 &&
2350		(q = ws[m & z.seed & SQMASK]) != null &&
2351		(s = q.top) != q.base &&
2352	<	(a = q.array) != null &&
2353	<	U.getObjectVolatile
2354	<	(a, j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE) == t &&
2355	<	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2356	<	if (q.array == a && q.top == s && // recheck
2357	<	U.compareAndSwapObject(a, j, t, null)) {
2358	<	q.top = s - 1;
2352	>	(a = q.array) != null) {
2353	>	long j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE;
2354	>	if (U.getObject(a, j) == t &&
2355	>	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2356	>	if (q.array == a && q.top == s && // recheck
2357	>	U.compareAndSwapObject(a, j, t, null)) {
2358	>	q.top = s - 1;
2359	>	q.qlock = 0;
2360	>	return true;
2361	>	}
2362		q.qlock = 0;
2273	–	return true;
2363		}
2275	–	q.qlock = 0;
2364		}
2365		return false;
2366		}
#	Line 2287 | Line 2375 | public class ForkJoinPool extends Abstra
2375		if (q != null && (a = q.array) != null && (m = (a.length - 1)) >= 0 &&
2376		root != null && root.status >= 0) {
2377		for (;;) {
2378	<	int s; Object o; CountedCompleter<?> task = null;
2378	>	int s, u; Object o; CountedCompleter<?> task = null;
2379		if ((s = q.top) - q.base > 0) {
2380		long j = ((m & (s - 1)) << ASHIFT) + ABASE;
2381		if ((o = U.getObject(a, j)) != null &&
#	Line 2310 | Line 2398 | public class ForkJoinPool extends Abstra
2398		}
2399		if (task != null)
2400		task.doExec();
2401	<	if (root.status < 0 || (int)(ctl >> AC_SHIFT) >= 0)
2401	>	if (root.status < 0 ||
2402	>	(u = (int)(ctl >>> 32)) >= 0 || (u >> UAC_SHIFT) >= 0)
2403		break;
2404		if (task == null) {
2405	<	if (helpSignal(root, q.poolIndex) >= 0)
2405	>	helpSignal(root, q.poolIndex);
2406	>	if (root.status >= 0)
2407		helpComplete(root, SHARED_QUEUE);
2408		break;
2409		}
#	Line 2328 | Line 2418 | public class ForkJoinPool extends Abstra
2418		static void externalHelpJoin(ForkJoinTask<?> t) {
2419		// Some hard-to-avoid overlap with tryExternalUnpush
2420		ForkJoinPool p; WorkQueue[] ws; WorkQueue q, w; Submitter z;
2421	<	ForkJoinTask<?>[] a;  int m, s, n; long j;
2422	<	if (t != null && t.status >= 0 &&
2421	>	ForkJoinTask<?>[] a;  int m, s, n;
2422	>	if (t != null &&
2423		(z = submitters.get()) != null &&
2424	<	(p = commonPool) != null &&
2424	>	(p = common) != null &&
2425		(ws = p.workQueues) != null &&
2426		(m = ws.length - 1) >= 0 &&
2427		(q = ws[m & z.seed & SQMASK]) != null &&
2428		(a = q.array) != null) {
2429	<	if ((s = q.top) != q.base &&
2430	<	U.getObjectVolatile
2431	<	(a, j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE) == t &&
2432	<	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2433	<	if (q.array == a && q.top == s &&
2434	<	U.compareAndSwapObject(a, j, t, null)) {
2435	<	q.top = s - 1;
2436	<	q.qlock = 0;
2437	<	t.doExec();
2429	>	int am = a.length - 1;
2430	>	if ((s = q.top) != q.base) {
2431	>	long j = ((am & (s - 1)) << ASHIFT) + ABASE;
2432	>	if (U.getObject(a, j) == t &&
2433	>	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2434	>	if (q.array == a && q.top == s &&
2435	>	U.compareAndSwapObject(a, j, t, null)) {
2436	>	q.top = s - 1;
2437	>	q.qlock = 0;
2438	>	t.doExec();
2439	>	}
2440	>	else
2441	>	q.qlock = 0;
2442		}
2349	–	else
2350	–	q.qlock = 0;
2443		}
2444		if (t.status >= 0) {
2445		if (t instanceof CountedCompleter)
#	Line 2358 | Line 2450 | public class ForkJoinPool extends Abstra
2450		}
2451		}
2452
2361	–	/**
2362	–	* Restricted version of helpQuiescePool for external callers
2363	–	*/
2364	–	static void externalHelpQuiescePool() {
2365	–	ForkJoinPool p; ForkJoinTask<?> t; WorkQueue q; int b;
2366	–	int r = ThreadLocalRandom.current().nextInt();
2367	–	if ((p = commonPool) != null &&
2368	–	(q = p.findNonEmptyStealQueue(r)) != null &&
2369	–	(b = q.base) - q.top < 0 &&
2370	–	(t = q.pollAt(b)) != null)
2371	–	t.doExec();
2372	–	}
2373	–
2453		// Exported methods
2454
2455		// Constructors
#	Line 2387 | Line 2466 | public class ForkJoinPool extends Abstra
2466		*         java.lang.RuntimePermission}{@code ("modifyThread")}
2467		*/
2468		public ForkJoinPool() {
2469	<	this(Runtime.getRuntime().availableProcessors(),
2469	>	this(Math.min(MAX_CAP, Runtime.getRuntime().availableProcessors()),
2470		defaultForkJoinWorkerThreadFactory, null, false);
2471		}
2472
#	Line 2442 | Line 2521 | public class ForkJoinPool extends Abstra
2521		throw new NullPointerException();
2522		if (parallelism <= 0 || parallelism > MAX_CAP)
2523		throw new IllegalArgumentException();
2445	–	this.parallelism = parallelism;
2524		this.factory = factory;
2525		this.ueh = handler;
2526	<	this.localMode = asyncMode ? FIFO_QUEUE : LIFO_QUEUE;
2526	>	this.config = parallelism | (asyncMode ? (FIFO_QUEUE << 16) : 0);
2527		long np = (long)(-parallelism); // offset ctl counts
2528		this.ctl = ((np << AC_SHIFT) & AC_MASK) | ((np << TC_SHIFT) & TC_MASK);
2529		int pn = nextPoolId();
#	Line 2462 | Line 2540 | public class ForkJoinPool extends Abstra
2540		ForkJoinPool(int parallelism, long ctl,
2541		ForkJoinWorkerThreadFactory factory,
2542		Thread.UncaughtExceptionHandler handler) {
2543	<	this.parallelism = parallelism;
2543	>	this.config = parallelism;
2544		this.ctl = ctl;
2545		this.factory = factory;
2546		this.ueh = handler;
2469	–	this.localMode = LIFO_QUEUE;
2547		this.workerNamePrefix = "ForkJoinPool.commonPool-worker-";
2548		}
2549
2550		/**
2551	<	* Returns the common pool instance.
2551	>	* Returns the common pool instance. This pool is statically
2552	>	* constructed; its run state is unaffected by attempts to {@link
2553	>	* #shutdown} or {@link #shutdownNow}. However this pool and any
2554	>	* ongoing processing are automatically terminated upon program
2555	>	* {@link System#exit}.  Any program that relies on asynchronous
2556	>	* task processing to complete before program termination should
2557	>	* invoke {@code commonPool().}{@link #awaitQuiescence}, before
2558	>	* exit.
2559		*
2560		* @return the common pool instance
2561	+	* @since 1.8
2562		*/
2563		public static ForkJoinPool commonPool() {
2564	<	return commonPool; // cannot be null (if so, a static init error)
2564	>	// assert common != null : "static init error";
2565	>	return common;
2566		}
2567
2568		// Execution methods
#	Line 2599 | Line 2685 | public class ForkJoinPool extends Abstra
2685		// In previous versions of this class, this method constructed
2686		// a task to run ForkJoinTask.invokeAll, but now external
2687		// invocation of multiple tasks is at least as efficient.
2688	<	List<ForkJoinTask<T>> fs = new ArrayList<ForkJoinTask<T>>(tasks.size());
2603	<	// Workaround needed because method wasn't declared with
2604	<	// wildcards in return type but should have been.
2605	<	@SuppressWarnings({"unchecked", "rawtypes"})
2606	<	List<Future<T>> futures = (List<Future<T>>) (List) fs;
2688	>	ArrayList<Future<T>> futures = new ArrayList<Future<T>>(tasks.size());
2689
2690		boolean done = false;
2691		try {
2692		for (Callable<T> t : tasks) {
2693		ForkJoinTask<T> f = new ForkJoinTask.AdaptedCallable<T>(t);
2694	+	futures.add(f);
2695		externalPush(f);
2613	–	fs.add(f);
2696		}
2697	<	for (ForkJoinTask<T> f : fs)
2698	<	f.quietlyJoin();
2697	>	for (int i = 0, size = futures.size(); i < size; i++)
2698	>	((ForkJoinTask<?>)futures.get(i)).quietlyJoin();
2699		done = true;
2700		return futures;
2701		} finally {
2702		if (!done)
2703	<	for (ForkJoinTask<T> f : fs)
2704	<	f.cancel(false);
2703	>	for (int i = 0, size = futures.size(); i < size; i++)
2704	>	futures.get(i).cancel(false);
2705		}
2706		}
2707
#	Line 2648 | Line 2730 | public class ForkJoinPool extends Abstra
2730		* @return the targeted parallelism level of this pool
2731		*/
2732		public int getParallelism() {
2733	<	return parallelism;
2733	>	return config & SMASK;
2734		}
2735
2736		/**
2737		* Returns the targeted parallelism level of the common pool.
2738		*
2739		* @return the targeted parallelism level of the common pool
2740	+	* @since 1.8
2741		*/
2742		public static int getCommonPoolParallelism() {
2743	<	return commonPoolParallelism;
2743	>	return commonParallelism;
2744		}
2745
2746		/**
#	Line 2669 | Line 2752 | public class ForkJoinPool extends Abstra
2752		* @return the number of worker threads
2753		*/
2754		public int getPoolSize() {
2755	<	return parallelism + (short)(ctl >>> TC_SHIFT);
2755	>	return (config & SMASK) + (short)(ctl >>> TC_SHIFT);
2756		}
2757
2758		/**
#	Line 2679 | Line 2762 | public class ForkJoinPool extends Abstra
2762		* @return {@code true} if this pool uses async mode
2763		*/
2764		public boolean getAsyncMode() {
2765	<	return localMode != 0;
2765	>	return (config >>> 16) == FIFO_QUEUE;
2766		}
2767
2768		/**
#	Line 2710 | Line 2793 | public class ForkJoinPool extends Abstra
2793		* @return the number of active threads
2794		*/
2795		public int getActiveThreadCount() {
2796	<	int r = parallelism + (int)(ctl >> AC_SHIFT);
2796	>	int r = (config & SMASK) + (int)(ctl >> AC_SHIFT);
2797		return (r <= 0) ? 0 : r; // suppress momentarily negative values
2798		}
2799
#	Line 2726 | Line 2809 | public class ForkJoinPool extends Abstra
2809		* @return {@code true} if all threads are currently idle
2810		*/
2811		public boolean isQuiescent() {
2812	<	return (int)(ctl >> AC_SHIFT) + parallelism == 0;
2812	>	return (int)(ctl >> AC_SHIFT) + (config & SMASK) == 0;
2813		}
2814
2815		/**
#	Line 2803 | Line 2886 | public class ForkJoinPool extends Abstra
2886		WorkQueue[] ws; WorkQueue w;
2887		if ((ws = workQueues) != null) {
2888		for (int i = 0; i < ws.length; i += 2) {
2889	<	if ((w = ws[i]) != null && w.queueSize() != 0)
2889	>	if ((w = ws[i]) != null && !w.isEmpty())
2890		return true;
2891		}
2892		}
#	Line 2889 | Line 2972 | public class ForkJoinPool extends Abstra
2972		}
2973		}
2974		}
2975	<	int pc = parallelism;
2975	>	int pc = (config & SMASK);
2976		int tc = pc + (short)(c >>> TC_SHIFT);
2977		int ac = pc + (int)(c >> AC_SHIFT);
2978		if (ac < 0) // ignore transient negative
#	Line 2915 | Line 2998 | public class ForkJoinPool extends Abstra
2998		* Possibly initiates an orderly shutdown in which previously
2999		* submitted tasks are executed, but no new tasks will be
3000		* accepted. Invocation has no effect on execution state if this
3001	<	* is the {@link #commonPool}, and no additional effect if
3001	>	* is the {@link #commonPool()}, and no additional effect if
3002		* already shut down.  Tasks that are in the process of being
3003		* submitted concurrently during the course of this method may or
3004		* may not be rejected.
#	Line 2933 | Line 3016 | public class ForkJoinPool extends Abstra
3016		/**
3017		* Possibly attempts to cancel and/or stop all tasks, and reject
3018		* all subsequently submitted tasks.  Invocation has no effect on
3019	<	* execution state if this is the {@link #commonPool}, and no
3019	>	* execution state if this is the {@link #commonPool()}, and no
3020		* additional effect if already shut down. Otherwise, tasks that
3021		* are in the process of being submitted or executed concurrently
3022		* during the course of this method may or may not be
#	Line 2962 | Line 3045 | public class ForkJoinPool extends Abstra
3045		public boolean isTerminated() {
3046		long c = ctl;
3047		return ((c & STOP_BIT) != 0L &&
3048	<	(short)(c >>> TC_SHIFT) == -parallelism);
3048	>	(short)(c >>> TC_SHIFT) == -(config & SMASK));
3049		}
3050
3051		/**
#	Line 2970 | Line 3053 | public class ForkJoinPool extends Abstra
3053		* commenced but not yet completed.  This method may be useful for
3054		* debugging. A return of {@code true} reported a sufficient
3055		* period after shutdown may indicate that submitted tasks have
3056	<	* ignored or suppressed interruption, or are waiting for IO,
3056	>	* ignored or suppressed interruption, or are waiting for I/O,
3057		* causing this executor not to properly terminate. (See the
3058		* advisory notes for class {@link ForkJoinTask} stating that
3059		* tasks should not normally entail blocking operations.  But if
#	Line 2981 | Line 3064 | public class ForkJoinPool extends Abstra
3064		public boolean isTerminating() {
3065		long c = ctl;
3066		return ((c & STOP_BIT) != 0L &&
3067	<	(short)(c >>> TC_SHIFT) != -parallelism);
3067	>	(short)(c >>> TC_SHIFT) != -(config & SMASK));
3068		}
3069
3070		/**
#	Line 2996 | Line 3079 | public class ForkJoinPool extends Abstra
3079		/**
3080		* Blocks until all tasks have completed execution after a
3081		* shutdown request, or the timeout occurs, or the current thread
3082	<	* is interrupted, whichever happens first. Note that the {@link
3083	<	* #commonPool()} never terminates until program shutdown so
3084	<	* this method will always time out.
3082	>	* is interrupted, whichever happens first. Because the {@link
3083	>	* #commonPool()} never terminates until program shutdown, when
3084	>	* applied to the common pool, this method is equivalent to {@link
3085	>	* #awaitQuiescence} but always returns {@code false}.
3086		*
3087		* @param timeout the maximum time to wait
3088		* @param unit the time unit of the timeout argument
#	Line 3008 | Line 3092 | public class ForkJoinPool extends Abstra
3092		*/
3093		public boolean awaitTermination(long timeout, TimeUnit unit)
3094		throws InterruptedException {
3095	+	if (Thread.interrupted())
3096	+	throw new InterruptedException();
3097	+	if (this == common) {
3098	+	awaitQuiescence(timeout, unit);
3099	+	return false;
3100	+	}
3101		long nanos = unit.toNanos(timeout);
3102		if (isTerminated())
3103		return true;
#	Line 3027 | Line 3117 | public class ForkJoinPool extends Abstra
3117		}
3118
3119		/**
3120	+	* If called by a ForkJoinTask operating in this pool, equivalent
3121	+	* in effect to {@link ForkJoinTask#helpQuiesce}. Otherwise,
3122	+	* waits and/or attempts to assist performing tasks until this
3123	+	* pool {@link #isQuiescent} or the indicated timeout elapses.
3124	+	*
3125	+	* @param timeout the maximum time to wait
3126	+	* @param unit the time unit of the timeout argument
3127	+	* @return {@code true} if quiescent; {@code false} if the
3128	+	* timeout elapsed.
3129	+	*/
3130	+	public boolean awaitQuiescence(long timeout, TimeUnit unit) {
3131	+	long nanos = unit.toNanos(timeout);
3132	+	ForkJoinWorkerThread wt;
3133	+	Thread thread = Thread.currentThread();
3134	+	if ((thread instanceof ForkJoinWorkerThread) &&
3135	+	(wt = (ForkJoinWorkerThread)thread).pool == this) {
3136	+	helpQuiescePool(wt.workQueue);
3137	+	return true;
3138	+	}
3139	+	long startTime = System.nanoTime();
3140	+	WorkQueue[] ws;
3141	+	int r = 0, m;
3142	+	boolean found = true;
3143	+	while (!isQuiescent() && (ws = workQueues) != null &&
3144	+	(m = ws.length - 1) >= 0) {
3145	+	if (!found) {
3146	+	if ((System.nanoTime() - startTime) > nanos)
3147	+	return false;
3148	+	Thread.yield(); // cannot block
3149	+	}
3150	+	found = false;
3151	+	for (int j = (m + 1) << 2; j >= 0; --j) {
3152	+	ForkJoinTask<?> t; WorkQueue q; int b;
3153	+	if ((q = ws[r++ & m]) != null && (b = q.base) - q.top < 0) {
3154	+	found = true;
3155	+	if ((t = q.pollAt(b)) != null) {
3156	+	if (q.base - q.top < 0)
3157	+	signalWork(q);
3158	+	t.doExec();
3159	+	}
3160	+	break;
3161	+	}
3162	+	}
3163	+	}
3164	+	return true;
3165	+	}
3166	+
3167	+	/**
3168	+	* Waits and/or attempts to assist performing tasks indefinitely
3169	+	* until the {@link #commonPool()} {@link #isQuiescent}.
3170	+	*/
3171	+	static void quiesceCommonPool() {
3172	+	common.awaitQuiescence(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
3173	+	}
3174	+
3175	+	/**
3176		* Interface for extending managed parallelism for tasks running
3177		* in {@link ForkJoinPool}s.
3178		*
#	Line 3125 | Line 3271 | public class ForkJoinPool extends Abstra
3271		if (t instanceof ForkJoinWorkerThread) {
3272		ForkJoinPool p = ((ForkJoinWorkerThread)t).pool;
3273		while (!blocker.isReleasable()) { // variant of helpSignal
3274	<	WorkQueue[] ws; WorkQueue q; int m, n;
3274	>	WorkQueue[] ws; WorkQueue q; int m, u;
3275		if ((ws = p.workQueues) != null && (m = ws.length - 1) >= 0) {
3276		for (int i = 0; i <= m; ++i) {
3277		if (blocker.isReleasable())
3278		return;
3279	<	if ((q = ws[i]) != null && (n = q.queueSize()) > 0) {
3280	<	p.signalWork(q, n);
3281	<	if ((int)(p.ctl >> AC_SHIFT) >= 0)
3279	>	if ((q = ws[i]) != null && q.base - q.top < 0) {
3280	>	p.signalWork(q);
3281	>	if ((u = (int)(p.ctl >>> 32)) >= 0 ||
3282	>	(u >> UAC_SHIFT) >= 0)
3283		break;
3284		}
3285		}
#	Line 3178 | Line 3325 | public class ForkJoinPool extends Abstra
3325		private static final long QLOCK;
3326
3327		static {
3328	<	// Establish common pool parameters
3182	<	// TBD: limit or report ignored exceptions?
3183	<
3184	<	int par = 0;
3185	<	ForkJoinWorkerThreadFactory fac = null;
3186	<	Thread.UncaughtExceptionHandler handler = null;
3187	<	try {
3188	<	String pp = System.getProperty(propPrefix + "parallelism");
3189	<	String hp = System.getProperty(propPrefix + "exceptionHandler");
3190	<	String fp = System.getProperty(propPrefix + "threadFactory");
3191	<	if (fp != null)
3192	<	fac = ((ForkJoinWorkerThreadFactory)ClassLoader.
3193	<	getSystemClassLoader().loadClass(fp).newInstance());
3194	<	if (hp != null)
3195	<	handler = ((Thread.UncaughtExceptionHandler)ClassLoader.
3196	<	getSystemClassLoader().loadClass(hp).newInstance());
3197	<	if (pp != null)
3198	<	par = Integer.parseInt(pp);
3199	<	} catch (Exception ignore) {
3200	<	}
3201	<
3202	<	int s; // initialize field offsets for CAS etc
3328	>	// initialize field offsets for CAS etc
3329		try {
3330		U = getUnsafe();
3331		Class<?> k = ForkJoinPool.class;
#	Line 3219 | Line 3345 | public class ForkJoinPool extends Abstra
3345		(wk.getDeclaredField("qlock"));
3346		Class<?> ak = ForkJoinTask[].class;
3347		ABASE = U.arrayBaseOffset(ak);
3348	<	s = U.arrayIndexScale(ak);
3349	<	ASHIFT = 31 - Integer.numberOfLeadingZeros(s);
3348	>	int scale = U.arrayIndexScale(ak);
3349	>	if ((scale & (scale - 1)) != 0)
3350	>	throw new Error("data type scale not a power of two");
3351	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
3352		} catch (Exception e) {
3353		throw new Error(e);
3354		}
3355	<	if ((s & (s-1)) != 0)
3356	<	throw new Error("data type scale not a power of two");
3355	>
3356	>	submitters = new ThreadLocal<Submitter>();
3357	>	ForkJoinWorkerThreadFactory fac = defaultForkJoinWorkerThreadFactory =
3358	>	new DefaultForkJoinWorkerThreadFactory();
3359	>	modifyThreadPermission = new RuntimePermission("modifyThread");
3360
3361		/*
3362	<	* For extra caution, computations to set up pool state are
3363	<	* here; the constructor just assigns these values to fields.
3362	>	* Establish common pool parameters.  For extra caution,
3363	>	* computations to set up common pool state are here; the
3364	>	* constructor just assigns these values to fields.
3365		*/
3366	<	ForkJoinWorkerThreadFactory defaultFac =
3367	<	defaultForkJoinWorkerThreadFactory =
3368	<	new DefaultForkJoinWorkerThreadFactory();
3369	<	if (fac == null)
3370	<	fac = defaultFac;
3366	>
3367	>	int par = 0;
3368	>	Thread.UncaughtExceptionHandler handler = null;
3369	>	try {  // TBD: limit or report ignored exceptions?
3370	>	String pp = System.getProperty
3371	>	("java.util.concurrent.ForkJoinPool.common.parallelism");
3372	>	String hp = System.getProperty
3373	>	("java.util.concurrent.ForkJoinPool.common.exceptionHandler");
3374	>	String fp = System.getProperty
3375	>	("java.util.concurrent.ForkJoinPool.common.threadFactory");
3376	>	if (fp != null)
3377	>	fac = ((ForkJoinWorkerThreadFactory)ClassLoader.
3378	>	getSystemClassLoader().loadClass(fp).newInstance());
3379	>	if (hp != null)
3380	>	handler = ((Thread.UncaughtExceptionHandler)ClassLoader.
3381	>	getSystemClassLoader().loadClass(hp).newInstance());
3382	>	if (pp != null)
3383	>	par = Integer.parseInt(pp);
3384	>	} catch (Exception ignore) {
3385	>	}
3386	>
3387		if (par <= 0)
3388		par = Runtime.getRuntime().availableProcessors();
3389		if (par > MAX_CAP)
3390		par = MAX_CAP;
3391	+	commonParallelism = par;
3392		long np = (long)(-par); // precompute initial ctl value
3393		long ct = ((np << AC_SHIFT) & AC_MASK) | ((np << TC_SHIFT) & TC_MASK);
3394
3395	<	commonPoolParallelism = par;
3247	<	commonPool = new ForkJoinPool(par, ct, fac, handler);
3248	<	modifyThreadPermission = new RuntimePermission("modifyThread");
3249	<	submitters = new ThreadLocal<Submitter>();
3395	>	common = new ForkJoinPool(par, ct, fac, handler);
3396		}
3397
3398		/**
#	Line 3259 | Line 3405 | public class ForkJoinPool extends Abstra
3405		private static sun.misc.Unsafe getUnsafe() {
3406		try {
3407		return sun.misc.Unsafe.getUnsafe();
3408	<	} catch (SecurityException se) {
3409	<	try {
3410	<	return java.security.AccessController.doPrivileged
3411	<	(new java.security
3412	<	.PrivilegedExceptionAction<sun.misc.Unsafe>() {
3413	<	public sun.misc.Unsafe run() throws Exception {
3414	<	java.lang.reflect.Field f = sun.misc
3415	<	.Unsafe.class.getDeclaredField("theUnsafe");
3416	<	f.setAccessible(true);
3417	<	return (sun.misc.Unsafe) f.get(null);
3418	<	}});
3419	<	} catch (java.security.PrivilegedActionException e) {
3420	<	throw new RuntimeException("Could not initialize intrinsics",
3421	<	e.getCause());
3422	<	}
3408	>	} catch (SecurityException tryReflectionInstead) {}
3409	>	try {
3410	>	return java.security.AccessController.doPrivileged
3411	>	(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
3412	>	public sun.misc.Unsafe run() throws Exception {
3413	>	Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class;
3414	>	for (java.lang.reflect.Field f : k.getDeclaredFields()) {
3415	>	f.setAccessible(true);
3416	>	Object x = f.get(null);
3417	>	if (k.isInstance(x))
3418	>	return k.cast(x);
3419	>	}
3420	>	throw new NoSuchFieldError("the Unsafe");
3421	>	}});
3422	>	} catch (java.security.PrivilegedActionException e) {
3423	>	throw new RuntimeException("Could not initialize intrinsics",
3424	>	e.getCause());
3425		}
3426		}
3279	–
3427		}

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