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

Comparing jsr166/src/jsr166e/ForkJoinPool.java (file contents):
Revision 1.12 by dl, Wed Nov 14 17:20:29 2012 UTC vs.
Revision 1.29 by jsr166, Fri Dec 14 16:33:42 2012 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 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	>	* @throw 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 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
984	<	ForkJoinPool p;
985	<	if ((p = pool) != null)
986	<	p.collectStealCount(this);
987	<	}
988	<	if (top != base) {       // process remaining local tasks
990	>	if (base - top < 0) {       // process remaining local tasks
991		if (mode == 0)
992		popAndExecAll();
993		else
994		pollAndExecAll();
995		}
996	+	++nsteals;
997	+	hint = -1;
998		}
999		}
1000
#	Line 1057 | Line 1061 | public class ForkJoinPool extends Abstra
1061		}
1062		}
1063
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	–
1064		// static fields (initialized in static initializer below)
1065
1066		/**
#	Line 1091 | Line 1071 | public class ForkJoinPool extends Abstra
1071		defaultForkJoinWorkerThreadFactory;
1072
1073		/**
1074	<	* Common (static) pool. Non-null for public use unless a static
1075	<	* construction exception, but internal usages null-check on use
1076	<	* to paranoically avoid potential initialization circularities
1077	<	* as well as to simplify generated code.
1074	>	* Per-thread submission bookkeeping. Shared across all pools
1075	>	* to reduce ThreadLocal pollution and because random motion
1076	>	* to avoid contention in one pool is likely to hold for others.
1077	>	* Lazily initialized on first submission (but null-checked
1078	>	* in other contexts to avoid unnecessary initialization).
1079		*/
1080	<	static final ForkJoinPool commonPool;
1080	>	static final ThreadLocal<Submitter> submitters;
1081
1082		/**
1083		* Permission required for callers of methods that may start or
#	Line 1105 | Line 1086 | public class ForkJoinPool extends Abstra
1086		private static final RuntimePermission modifyThreadPermission;
1087
1088		/**
1089	<	* Per-thread submission bookkeeping. Shared across all pools
1090	<	* to reduce ThreadLocal pollution and because random motion
1091	<	* to avoid contention in one pool is likely to hold for others.
1092	<	* Lazily initialized on first submission (but null-checked
1112	<	* in other contexts to avoid unnecessary initialization).
1089	>	* Common (static) pool. Non-null for public use unless a static
1090	>	* construction exception, but internal usages null-check on use
1091	>	* to paranoically avoid potential initialization circularities
1092	>	* as well as to simplify generated code.
1093		*/
1094	<	static final ThreadLocal<Submitter> submitters;
1094	>	static final ForkJoinPool commonPool;
1095
1096		/**
1097		* Common pool parallelism. Must equal commonPool.parallelism.
#	Line 1149 | Line 1129 | public class ForkJoinPool extends Abstra
1129		private static final long FAST_IDLE_TIMEOUT =  200L * 1000L * 1000L;
1130
1131		/**
1132	+	* Tolerance for idle timeouts, to cope with timer undershoots
1133	+	*/
1134	+	private static final long TIMEOUT_SLOP = 2000000L; // 20ms
1135	+
1136	+	/**
1137		* The maximum stolen->joining link depth allowed in method
1138		* tryHelpStealer.  Must be a power of two.  Depths for legitimate
1139		* chains are unbounded, but we use a fixed constant to avoid
#	Line 1248 | Line 1233 | public class ForkJoinPool extends Abstra
1233		static final int FIFO_QUEUE          =  1;
1234		static final int SHARED_QUEUE        = -1;
1235
1236	+	// bounds for #steps in scan loop -- must be power 2 minus 1
1237	+	private static final int MIN_SCAN    = 0x1ff;   // cover estimation slop
1238	+	private static final int MAX_SCAN    = 0x1ffff; // 4 * max workers
1239	+
1240		// Instance fields
1241
1242		/*
1243	<	* Field layout order in this class tends to matter more than one
1244	<	* would like. Runtime layout order is only loosely related to
1243	>	* Field layout of this class tends to matter more than one would
1244	>	* like. Runtime layout order is only loosely related to
1245		* declaration order and may differ across JVMs, but the following
1246		* empirically works OK on current JVMs.
1247		*/
1248	+
1249	+	// Heuristic padding to ameliorate unfortunate memory placements
1250	+	volatile long pad00, pad01, pad02, pad03, pad04, pad05, pad06;
1251	+
1252		volatile long stealCount;                  // collects worker counts
1253		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
1254		volatile int plock;                        // shutdown status and seqLock
1255	+	volatile int indexSeed;                    // worker/submitter index seed
1256	+	final int config;                          // mode and parallelism level
1257		WorkQueue[] workQueues;                    // main registry
1258	<	final ForkJoinWorkerThreadFactory factory; // factory for new workers
1258	>	final ForkJoinWorkerThreadFactory factory;
1259		final Thread.UncaughtExceptionHandler ueh; // per-worker UEH
1260		final String workerNamePrefix;             // to create worker name string
1261
1262	+	volatile Object pad10, pad11, pad12, pad13, pad14, pad15, pad16, pad17;
1263	+	volatile Object pad18, pad19, pad1a, pad1b;
1264	+
1265		/*
1266		* Acquires the plock lock to protect worker array and related
1267		* updates. This method is called only if an initial CAS on plock
#	Line 1283 | Line 1278 | public class ForkJoinPool extends Abstra
1278		if (((ps = plock) & PL_LOCK) == 0 &&
1279		U.compareAndSwapInt(this, PLOCK, ps, nps = ps + PL_LOCK))
1280		return nps;
1281	<	else if (r == 0)
1282	<	r = ThreadLocalRandom.current().nextInt(); // randomize spins
1281	>	else if (r == 0) { // randomize spins if possible
1282	>	Thread t = Thread.currentThread(); WorkQueue w; Submitter z;
1283	>	if ((t instanceof ForkJoinWorkerThread) &&
1284	>	(w = ((ForkJoinWorkerThread)t).workQueue) != null)
1285	>	r = w.seed;
1286	>	else if ((z = submitters.get()) != null)
1287	>	r = z.seed;
1288	>	else
1289	>	r = 1;
1290	>	}
1291		else if (spins >= 0) {
1292		r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
1293		if (r >= 0)
1294		--spins;
1295		}
1296		else if (U.compareAndSwapInt(this, PLOCK, ps, ps | PL_SIGNAL)) {
1297	<	synchronized(this) {
1297	>	synchronized (this) {
1298		if ((plock & PL_SIGNAL) != 0) {
1299		try {
1300		wait();
#	Line 1315 | Line 1318 | public class ForkJoinPool extends Abstra
1318		*/
1319		private void releasePlock(int ps) {
1320		plock = ps;
1321	<	synchronized(this) { notifyAll(); }
1321	>	synchronized (this) { notifyAll(); }
1322	>	}
1323	>
1324	>	/**
1325	>	* Performs secondary initialization, called when plock is zero.
1326	>	* Creates workQueue array and sets plock to a valid value.  The
1327	>	* lock body must be exception-free (so no try/finally) so we
1328	>	* optimistically allocate new array outside the lock and throw
1329	>	* away if (very rarely) not needed. (A similar tactic is used in
1330	>	* fullExternalPush.)  Because the plock seq value can eventually
1331	>	* wrap around zero, this method harmlessly fails to reinitialize
1332	>	* if workQueues exists, while still advancing plock.
1333	>	*
1334	>	* Additionally tries to create the first worker.
1335	>	*/
1336	>	private void initWorkers() {
1337	>	WorkQueue[] ws, nws; int ps;
1338	>	int p = config & SMASK;        // find power of two table size
1339	>	int n = (p > 1) ? p - 1 : 1;   // ensure at least 2 slots
1340	>	n |= n >>> 1; n |= n >>> 2; n |= n >>> 4; n |= n >>> 8; n |= n >>> 16;
1341	>	n = (n + 1) << 1;
1342	>	if ((ws = workQueues) == null || ws.length == 0)
1343	>	nws = new WorkQueue[n];
1344	>	else
1345	>	nws = null;
1346	>	if (((ps = plock) & PL_LOCK) != 0 ||
1347	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1348	>	ps = acquirePlock();
1349	>	if (((ws = workQueues) == null || ws.length == 0) && nws != null)
1350	>	workQueues = nws;
1351	>	int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1352	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1353	>	releasePlock(nps);
1354	>	tryAddWorker();
1355	>	}
1356	>
1357	>	/**
1358	>	* Tries to create and start one worker if fewer than target
1359	>	* parallelism level exist. Adjusts counts etc on failure.
1360	>	*/
1361	>	private void tryAddWorker() {
1362	>	long c; int u;
1363	>	while ((u = (int)((c = ctl) >>> 32)) < 0 &&
1364	>	(u & SHORT_SIGN) != 0 && (int)c == 0) {
1365	>	long nc = (long)(((u + UTC_UNIT) & UTC_MASK) |
1366	>	((u + UAC_UNIT) & UAC_MASK)) << 32;
1367	>	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1368	>	ForkJoinWorkerThreadFactory fac;
1369	>	Throwable ex = null;
1370	>	ForkJoinWorkerThread wt = null;
1371	>	try {
1372	>	if ((fac = factory) != null &&
1373	>	(wt = fac.newThread(this)) != null) {
1374	>	wt.start();
1375	>	break;
1376	>	}
1377	>	} catch (Throwable e) {
1378	>	ex = e;
1379	>	}
1380	>	deregisterWorker(wt, ex);
1381	>	break;
1382	>	}
1383	>	}
1384		}
1385
1386		//  Registering and deregistering workers
1387
1388		/**
1389	<	* Callback from ForkJoinWorkerThread constructor to establish its
1390	<	* poolIndex and record its WorkQueue. To avoid scanning bias due
1391	<	* to packing entries in front of the workQueues array, we treat
1392	<	* the array as a simple power-of-two hash table using per-thread
1393	<	* seed as hash, expanding as needed.
1394	<	*
1395	<	* @param w the worker's queue
1396	<	*/
1397	<	final void registerWorker(WorkQueue w) {
1398	<	int s, ps; // generate a rarely colliding candidate index seed
1399	<	do {} while (!U.compareAndSwapInt(this, INDEXSEED,
1400	<	s = indexSeed, s += SEED_INCREMENT) ||
1389	>	* Callback from ForkJoinWorkerThread to establish and record its
1390	>	* WorkQueue. To avoid scanning bias due to packing entries in
1391	>	* front of the workQueues array, we treat the array as a simple
1392	>	* power-of-two hash table using per-thread seed as hash,
1393	>	* expanding as needed.
1394	>	*
1395	>	* @param wt the worker thread
1396	>	* @return the worker's queue
1397	>	*/
1398	>	final WorkQueue registerWorker(ForkJoinWorkerThread wt) {
1399	>	Thread.UncaughtExceptionHandler handler; WorkQueue[] ws; int s, ps;
1400	>	wt.setDaemon(true);
1401	>	if ((handler = ueh) != null)
1402	>	wt.setUncaughtExceptionHandler(handler);
1403	>	do {} while (!U.compareAndSwapInt(this, INDEXSEED, s = indexSeed,
1404	>	s += SEED_INCREMENT) ||
1405		s == 0); // skip 0
1406	+	WorkQueue w = new WorkQueue(this, wt, config >>> 16, s);
1407		if (((ps = plock) & PL_LOCK) != 0 ||
1408		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1409		ps = acquirePlock();
1410		int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1411		try {
1412	<	WorkQueue[] ws;
1343	<	if (w != null && (ws = workQueues) != null) {
1344	<	w.seed = s;
1412	>	if ((ws = workQueues) != null) {    // skip if shutting down
1413		int n = ws.length, m = n - 1;
1414	<	int r = (s << 1) | 1;               // use odd-numbered indices
1415	<	if (ws[r &= m] != null) {           // collision
1416	<	int probes = 0;                 // step by approx half size
1414	>	int r = (s << 1) | 1;           // use odd-numbered indices
1415	>	if (ws[r &= m] != null) {       // collision
1416	>	int probes = 0;             // step by approx half size
1417		int step = (n <= 4) ? 2 : ((n >>> 1) & EVENMASK) + 2;
1418		while (ws[r = (r + step) & m] != null) {
1419		if (++probes >= n) {
#	Line 1355 | Line 1423 | public class ForkJoinPool extends Abstra
1423		}
1424		}
1425		}
1426	<	w.eventCount = w.poolIndex = r;     // establish before recording
1426	>	w.eventCount = w.poolIndex = r; // volatile write orders
1427		ws[r] = w;
1428		}
1429		} finally {
1430		if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1431		releasePlock(nps);
1432		}
1433	+	wt.setName(workerNamePrefix.concat(Integer.toString(w.poolIndex)));
1434	+	return w;
1435		}
1436
1437		/**
#	Line 1377 | Line 1447 | public class ForkJoinPool extends Abstra
1447		WorkQueue w = null;
1448		if (wt != null && (w = wt.workQueue) != null) {
1449		int ps;
1380	–	collectStealCount(w);
1450		w.qlock = -1;                // ensure set
1451	+	long ns = w.nsteals, sc;     // collect steal count
1452	+	do {} while (!U.compareAndSwapLong(this, STEALCOUNT,
1453	+	sc = stealCount, sc + ns));
1454		if (((ps = plock) & PL_LOCK) != 0 ||
1455		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1456		ps = acquirePlock();
#	Line 1400 | Line 1472 | public class ForkJoinPool extends Abstra
1472		((c - TC_UNIT) & TC_MASK) |
1473		(c & ~(AC_MASK|TC_MASK)))));
1474
1475	<	if (!tryTerminate(false, false) && w != null) {
1475	>	if (!tryTerminate(false, false) && w != null && w.array != null) {
1476		w.cancelAll();                  // cancel remaining tasks
1477	<	if (w.array != null)            // suppress signal if never ran
1478	<	signalWork(null, 1);        // wake up or create replacement
1479	<	if (ex == null)                 // help clean refs on way out
1480	<	ForkJoinTask.helpExpungeStaleExceptions();
1477	>	int e, u, i, n; WorkQueue[] ws; WorkQueue v; Thread p;
1478	>	while ((u = (int)((c = ctl) >>> 32)) < 0) {
1479	>	if ((e = (int)c) > 0) {     // activate or create replacement
1480	>	if ((ws = workQueues) != null &&
1481	>	ws.length > (i = e & SMASK) &&
1482	>	(v = ws[i]) != null && v.eventCount == (e | INT_SIGN)) {
1483	>	long nc = (((long)(v.nextWait & E_MASK)) |
1484	>	((long)(u + UAC_UNIT) << 32));
1485	>	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1486	>	v.eventCount = (e + E_SEQ) & E_MASK;
1487	>	if ((p = v.parker) != null)
1488	>	U.unpark(p);
1489	>	break;
1490	>	}
1491	>	}
1492	>	else
1493	>	break;
1494	>	}
1495	>	else {
1496	>	if ((short)u < 0)
1497	>	tryAddWorker();
1498	>	break;
1499	>	}
1500	>	}
1501		}
1502	<
1503	<	if (ex != null)                     // rethrow
1502	>	if (ex == null)                     // help clean refs on way out
1503	>	ForkJoinTask.helpExpungeStaleExceptions();
1504	>	else                                // rethrow
1505		ForkJoinTask.rethrow(ex);
1506		}
1507
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	–
1508		// Submissions
1509
1510		/**
#	Line 1445 | Line 1521 | public class ForkJoinPool extends Abstra
1521		(ws = workQueues) != null && (m = (ws.length - 1)) >= 0 &&
1522		(q = ws[m & z.seed & SQMASK]) != null &&
1523		U.compareAndSwapInt(q, QLOCK, 0, 1)) { // lock
1524	<	int s = q.top, n;
1525	<	if ((a = q.array) != null && a.length > (n = s + 1 - q.base)) {
1526	<	U.putObject(a, (long)(((a.length - 1) & s) << ASHIFT) + ABASE,
1527	<	task);
1524	>	int b = q.base, s = q.top, n, an;
1525	>	if ((a = q.array) != null && (an = a.length) > (n = s + 1 - b)) {
1526	>	int j = (((an - 1) & s) << ASHIFT) + ABASE;
1527	>	U.putOrderedObject(a, j, task);
1528		q.top = s + 1;                     // push on to deque
1529		q.qlock = 0;
1530	<	if (n <= 1)
1531	<	signalWork(q, 1);
1530	>	if (n <= 2)
1531	>	signalWork(q);
1532		return;
1533		}
1534		q.qlock = 0;
#	Line 1463 | Line 1539 | public class ForkJoinPool extends Abstra
1539		/**
1540		* Full version of externalPush. This method is called, among
1541		* other times, upon the first submission of the first task to the
1542	<	* pool, so must perform secondary initialization: creating
1543	<	* workQueue array and setting plock to a valid value. It also
1544	<	* detects first submission by an external thread by looking up
1545	<	* its ThreadLocal, and creates a new shared queue if the one at
1546	<	* index if empty or contended. The lock bodies must be
1547	<	* exception-free (so no try/finally) so we optimistically
1548	<	* allocate new queues/arrays outside the locks and throw them
1473	<	* away if (very rarely) not needed. Note that the plock seq value
1474	<	* can eventually wrap around zero, but if so harmlessly fails to
1475	<	* reinitialize.
1542	>	* pool, so must perform secondary initialization (via
1543	>	* initWorkers). It also detects first submission by an external
1544	>	* thread by looking up its ThreadLocal, and creates a new shared
1545	>	* queue if the one at index if empty or contended. The plock lock
1546	>	* body must be exception-free (so no try/finally) so we
1547	>	* optimistically allocate new queues outside the lock and throw
1548	>	* them away if (very rarely) not needed.
1549		*/
1550		private void fullExternalPush(ForkJoinTask<?> task) {
1551	<	for (Submitter z = null;;) {
1552	<	WorkQueue[] ws; WorkQueue q; int ps, m, r, s;
1553	<	if ((ps = plock) < 0)
1551	>	int r = 0; // random index seed
1552	>	for (Submitter z = submitters.get();;) {
1553	>	WorkQueue[] ws; WorkQueue q; int ps, m, k;
1554	>	if (z == null) {
1555	>	if (U.compareAndSwapInt(this, INDEXSEED, r = indexSeed,
1556	>	r += SEED_INCREMENT) && r != 0)
1557	>	submitters.set(z = new Submitter(r));
1558	>	}
1559	>	else if (r == 0) {               // move to a different index
1560	>	r = z.seed;
1561	>	r ^= r << 13;                // same xorshift as WorkQueues
1562	>	r ^= r >>> 17;
1563	>	z.seed = r ^ (r << 5);
1564	>	}
1565	>	else if ((ps = plock) < 0)
1566		throw new RejectedExecutionException();
1567	<	else if ((ws = workQueues) == null || (m = ws.length - 1) < 0) {
1568	<	int n = parallelism - 1; n |= n >>> 1; n |= n >>> 2;
1569	<	n |= n >>> 4; n |= n >>> 8; n |= n >>> 16;
1570	<	WorkQueue[] nws = new WorkQueue[(n + 1) << 1]; // power of two
1571	<	if ((ps & PL_LOCK) != 0 ||
1567	>	else if (ps == 0 || (ws = workQueues) == null ||
1568	>	(m = ws.length - 1) < 0)
1569	>	initWorkers();
1570	>	else if ((q = ws[k = r & m & SQMASK]) != null) {
1571	>	if (q.qlock == 0 && U.compareAndSwapInt(q, QLOCK, 0, 1)) {
1572	>	ForkJoinTask<?>[] a = q.array;
1573	>	int s = q.top;
1574	>	boolean submitted = false;
1575	>	try {                      // locked version of push
1576	>	if ((a != null && a.length > s + 1 - q.base) ||
1577	>	(a = q.growArray()) != null) {   // must presize
1578	>	int j = (((a.length - 1) & s) << ASHIFT) + ABASE;
1579	>	U.putOrderedObject(a, j, task);
1580	>	q.top = s + 1;
1581	>	submitted = true;
1582	>	}
1583	>	} finally {
1584	>	q.qlock = 0;  // unlock
1585	>	}
1586	>	if (submitted) {
1587	>	signalWork(q);
1588	>	return;
1589	>	}
1590	>	}
1591	>	r = 0; // move on failure
1592	>	}
1593	>	else if (((ps = plock) & PL_LOCK) == 0) { // create new queue
1594	>	q = new WorkQueue(this, null, SHARED_QUEUE, r);
1595	>	if (((ps = plock) & PL_LOCK) != 0 ||
1596		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1597		ps = acquirePlock();
1598	<	if ((ws = workQueues) == null)
1599	<	workQueues = nws;
1598	>	if ((ws = workQueues) != null && k < ws.length && ws[k] == null)
1599	>	ws[k] = q;
1600		int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1601		if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1602		releasePlock(nps);
1603		}
1604	<	else if (z == null && (z = submitters.get()) == null) {
1605	<	if (U.compareAndSwapInt(this, INDEXSEED,
1497	<	s = indexSeed, s += SEED_INCREMENT) &&
1498	<	s != 0) // skip 0
1499	<	submitters.set(z = new Submitter(s));
1500	<	}
1501	<	else {
1502	<	int k = (r = z.seed) & m & SQMASK;
1503	<	if ((q = ws[k]) == null && (ps & PL_LOCK) == 0) {
1504	<	(q = new WorkQueue(this, null, SHARED_QUEUE)).poolIndex = k;
1505	<	if (((ps = plock) & PL_LOCK) != 0 ||
1506	<	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1507	<	ps = acquirePlock();
1508	<	WorkQueue w = null;
1509	<	if ((ws = workQueues) != null && k < ws.length &&
1510	<	(w = ws[k]) == null)
1511	<	ws[k] = q;
1512	<	else
1513	<	q = w;
1514	<	int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1515	<	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1516	<	releasePlock(nps);
1517	<	}
1518	<	if (q != null && q.qlock == 0 && q.fullPush(task, false))
1519	<	return;
1520	<	r ^= r << 13;                // same xorshift as WorkQueues
1521	<	r ^= r >>> 17;
1522	<	z.seed = r ^= r << 5;        // move to a different index
1523	<	}
1604	>	else
1605	>	r = 0; // try elsewhere while lock held
1606		}
1607		}
1608
#	Line 1535 | Line 1617 | public class ForkJoinPool extends Abstra
1617		}
1618
1619		/**
1620	<	* 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.
1620	>	* Tries to create or activate a worker if too few are active.
1621		*
1622	<	* @param q if non-null, the queue holding tasks to be signalled
1544	<	* @param signals the target number of signals.
1622	>	* @param q the (non-null) queue holding tasks to be signalled
1623		*/
1624	<	final void signalWork(WorkQueue q, int signals) {
1625	<	long c; int e, u, i; WorkQueue[] ws; WorkQueue w; Thread p;
1624	>	final void signalWork(WorkQueue q) {
1625	>	int hint = q.poolIndex;
1626	>	long c; int e, u, i, n; WorkQueue[] ws; WorkQueue w; Thread p;
1627		while ((u = (int)((c = ctl) >>> 32)) < 0) {
1628		if ((e = (int)c) > 0) {
1629		if ((ws = workQueues) != null && ws.length > (i = e & SMASK) &&
#	Line 1552 | Line 1631 | public class ForkJoinPool extends Abstra
1631		long nc = (((long)(w.nextWait & E_MASK)) |
1632		((long)(u + UAC_UNIT) << 32));
1633		if (U.compareAndSwapLong(this, CTL, c, nc)) {
1634	+	w.hint = hint;
1635		w.eventCount = (e + E_SEQ) & E_MASK;
1636		if ((p = w.parker) != null)
1637		U.unpark(p);
1638	<	if (--signals <= 0)
1559	<	break;
1638	>	break;
1639		}
1640	<	else
1562	<	signals = 1;
1563	<	if ((q != null && q.queueSize() == 0))
1640	>	if (q.top - q.base <= 0)
1641		break;
1642		}
1643		else
1644		break;
1645		}
1646	<	else if (e == 0 && (u & SHORT_SIGN) != 0) {
1647	<	long nc = (long)(((u + UTC_UNIT) & UTC_MASK) |
1648	<	((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
1646	>	else {
1647	>	if ((short)u < 0)
1648	>	tryAddWorker();
1649		break;
1650	+	}
1651		}
1652		}
1653
#	Line 1599 | Line 1657 | public class ForkJoinPool extends Abstra
1657		* Top-level runloop for workers, called by ForkJoinWorkerThread.run.
1658		*/
1659		final void runWorker(WorkQueue w) {
1660	<	// initialize queue array in this thread
1603	<	w.array = new ForkJoinTask<?>[WorkQueue.INITIAL_QUEUE_CAPACITY];
1660	>	w.growArray(); // allocate queue
1661		do { w.runTask(scan(w)); } while (w.qlock >= 0);
1662		}
1663
#	Line 1612 | Line 1669 | public class ForkJoinPool extends Abstra
1669		* contention, or state changes that indicate possible success on
1670		* re-invocation.
1671		*
1672	<	* The scan searches for tasks across a random permutation of
1673	<	* queues (starting at a random index and stepping by a random
1674	<	* relative prime, checking each at least once).  The scan
1675	<	* terminates upon either finding a non-empty queue, or completing
1676	<	* the sweep. If the worker is not inactivated, it takes and
1677	<	* returns a task from this queue. Otherwise, if not activated, it
1678	<	* signals workers (that may include itself) and returns so caller
1679	<	* can retry. Also returns for trtry if the worker array may have
1680	<	* changed during an empty scan.  On failure to find a task, we
1681	<	* take one of the following actions, after which the caller will
1682	<	* retry calling this method unless terminated.
1672	>	* The scan searches for tasks across queues (starting at a random
1673	>	* index, and relying on registerWorker to irregularly scatter
1674	>	* them within array to avoid bias), checking each at least twice.
1675	>	* The scan terminates upon either finding a non-empty queue, or
1676	>	* completing the sweep. If the worker is not inactivated, it
1677	>	* takes and returns a task from this queue. Otherwise, if not
1678	>	* activated, it signals workers (that may include itself) and
1679	>	* returns so caller can retry. Also returns for true if the
1680	>	* worker array may have changed during an empty scan.  On failure
1681	>	* to find a task, we take one of the following actions, after
1682	>	* which the caller will retry calling this method unless
1683	>	* terminated.
1684		*
1685		* * If pool is terminating, terminate the worker.
1686		*
#	Line 1632 | Line 1690 | public class ForkJoinPool extends Abstra
1690		* termination and possibly shrink pool.
1691		*
1692		* * If already enqueued and none of the above apply, possibly
1693	<	* (with 1/2 probablility) park awaiting signal, else lingering to
1693	>	* (with 1/2 probability) park awaiting signal, else lingering to
1694		* help scan and signal.
1695		*
1696		* @param w the worker (via its WorkQueue)
1697		* @return a task or null if none found
1698		*/
1699		private final ForkJoinTask<?> scan(WorkQueue w) {
1700	<	WorkQueue[] ws; WorkQueue q;           // first update random seed
1701	<	int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
1702	<	int ps = plock, m;                     // volatile read order matters
1703	<	if ((ws = workQueues) != null && (m = ws.length - 1) > 0) {
1704	<	int ec = w.eventCount;             // ec is negative if inactive
1705	<	int step = (r >>> 16) | 1;         // relatively prime
1706	<	for (int j = (m + 1) << 2;  ; --j, r += step) {
1707	<	ForkJoinTask<?> t; ForkJoinTask<?>[] a; int b, n;
1708	<	if ((q = ws[r & m]) != null && (b = q.base) - q.top < 0 &&
1709	<	(a = q.array) != null) {   // probably nonempty
1700	>	WorkQueue[] ws; int m;
1701	>	int ps = plock;                          // read plock before ws
1702	>	if (w != null && (ws = workQueues) != null && (m = ws.length - 1) >= 0) {
1703	>	int ec = w.eventCount;               // ec is negative if inactive
1704	>	int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
1705	>	int j = ((m + m + 1) | MIN_SCAN) & MAX_SCAN;
1706	>	do {
1707	>	WorkQueue q; ForkJoinTask<?>[] a; int b;
1708	>	if ((q = ws[(r + j) & m]) != null && (b = q.base) - q.top < 0 &&
1709	>	(a = q.array) != null) {     // probably nonempty
1710		int i = (((a.length - 1) & b) << ASHIFT) + ABASE;
1711	<	t = (ForkJoinTask<?>)U.getObjectVolatile(a, i);
1711	>	ForkJoinTask<?> t = (ForkJoinTask<?>)
1712	>	U.getObjectVolatile(a, i);
1713		if (q.base == b && ec >= 0 && t != null &&
1714		U.compareAndSwapObject(a, i, t, null)) {
1715	<	if ((n = q.top - (q.base = b + 1)) > 0)
1716	<	signalWork(q, n);
1717	<	return t;              // taken
1718	<	}
1719	<	if (j < m || (ec < 0 && (ec = w.eventCount) < 0)) {
1720	<	if ((n = q.queueSize() - 1) > 0)
1721	<	signalWork(q, n);
1722	<	break;                 // let caller retry after signal
1723	<	}
1724	<	}
1725	<	else if (j < 0) {              // end of scan
1726	<	long c = ctl; int e;
1727	<	if (plock != ps)           // incomplete sweep
1728	<	break;
1729	<	if ((e = (int)c) < 0)      // pool is terminating
1730	<	w.qlock = -1;
1731	<	else if (ec >= 0) {        // try to enqueue/inactivate
1732	<	long nc = ((long)ec |
1733	<	((c - AC_UNIT) & (AC_MASK|TC_MASK)));
1734	<	w.nextWait = e;
1735	<	w.eventCount = ec | INT_SIGN; // mark as inactive
1736	<	if (ctl != c ||
1737	<	!U.compareAndSwapLong(this, CTL, c, nc))
1738	<	w.eventCount = ec; // unmark on CAS failure
1739	<	else if ((int)(c >> AC_SHIFT) == 1 - parallelism)
1740	<	idleAwaitWork(w, nc, c);  // quiescent
1741	<	}
1742	<	else if (w.seed >= 0 && w.eventCount < 0) {
1743	<	Thread wt = Thread.currentThread();
1744	<	Thread.interrupted();  // clear status
1745	<	U.putObject(wt, PARKBLOCKER, this);
1746	<	w.parker = wt;         // emulate LockSupport.park
1747	<	if (w.eventCount < 0)  // recheck
1748	<	U.park(false, 0L);
1749	<	w.parker = null;
1750	<	U.putObject(wt, PARKBLOCKER, null);
1751	<	}
1752	<	break;
1715	>	if ((q.base = b + 1) - q.top < 0)
1716	>	signalWork(q);
1717	>	return t;                // taken
1718	>	}
1719	>	else if ((ec < 0 || j < m) && (int)(ctl >> AC_SHIFT) <= 0) {
1720	>	w.hint = (r + j) & m;    // help signal below
1721	>	break;                   // cannot take
1722	>	}
1723	>	}
1724	>	} while (--j >= 0);
1725	>
1726	>	long c, sc; int e, ns, h;
1727	>	if ((h = w.hint) < 0) {
1728	>	if ((ns = w.nsteals) != 0) {
1729	>	if (U.compareAndSwapLong(this, STEALCOUNT,
1730	>	sc = stealCount, sc + ns))
1731	>	w.nsteals = 0;           // collect steals
1732	>	}
1733	>	else if (plock != ps)            // consistency check
1734	>	;                            // skip
1735	>	else if ((e = (int)(c = ctl)) < 0)
1736	>	w.qlock = -1;                // pool is terminating
1737	>	else if (ec >= 0) {              // try to enqueue/inactivate
1738	>	long nc = ((long)ec | ((c - AC_UNIT) & (AC_MASK|TC_MASK)));
1739	>	w.nextWait = e;              // link and mark inactive
1740	>	w.eventCount = ec | INT_SIGN;
1741	>	if (ctl != c || !U.compareAndSwapLong(this, CTL, c, nc))
1742	>	w.eventCount = ec;       // unmark on CAS failure
1743	>	else if ((int)(c >> AC_SHIFT) == 1 - (config & SMASK))
1744	>	idleAwaitWork(w, nc, c);
1745	>	}
1746	>	else if (w.eventCount < 0) {     // block
1747	>	Thread wt = Thread.currentThread();
1748	>	Thread.interrupted();        // clear status
1749	>	U.putObject(wt, PARKBLOCKER, this);
1750	>	w.parker = wt;               // emulate LockSupport.park
1751	>	if (w.eventCount < 0)        // recheck
1752	>	U.park(false, 0L);
1753	>	w.parker = null;
1754	>	U.putObject(wt, PARKBLOCKER, null);
1755		}
1756		}
1757	+	if (h >= 0 || w.hint >= 0)           // signal others before retry
1758	+	helpSignalHint(w);
1759		}
1760		return null;
1761		}
#	Line 1710 | Line 1773 | public class ForkJoinPool extends Abstra
1773		* @param prevCtl the ctl value to restore if thread is terminated
1774		*/
1775		private void idleAwaitWork(WorkQueue w, long currentCtl, long prevCtl) {
1776	<	if (w.eventCount < 0 &&
1777	<	(this == commonPool || !tryTerminate(false, false)) &&
1715	<	(int)prevCtl != 0) {
1776	>	if (w != null && w.eventCount < 0 &&
1777	>	!tryTerminate(false, false) && (int)prevCtl != 0) {
1778		int dc = -(short)(currentCtl >>> TC_SHIFT);
1779		long parkTime = dc < 0 ? FAST_IDLE_TIMEOUT: (dc + 1) * IDLE_TIMEOUT;
1780	<	long deadline = System.nanoTime() + parkTime - 100000L; // 1ms slop
1780	>	long deadline = System.nanoTime() + parkTime - TIMEOUT_SLOP;
1781		Thread wt = Thread.currentThread();
1782		while (ctl == currentCtl) {
1783		Thread.interrupted();  // timed variant of version in scan()
#	Line 1738 | Line 1800 | public class ForkJoinPool extends Abstra
1800		}
1801
1802		/**
1803	<	* Scans through queues looking for work while joining a task;
1804	<	* if any are present, signals.
1803	>	* Scans through queues looking for work while joining a task; if
1804	>	* any present, signals. May return early if more signalling is
1805	>	* detectably unneeded.
1806		*
1807	<	* @param task to return early if done
1807	>	* @param task return early if done
1808		* @param origin an index to start scan
1809		*/
1810	<	final int helpSignal(ForkJoinTask<?> task, int origin) {
1811	<	WorkQueue[] ws; WorkQueue q; int m, n, s;
1812	<	if (task != null && (ws = workQueues) != null &&
1813	<	(m = ws.length - 1) >= 0) {
1814	<	for (int i = 0; i <= m; ++i) {
1815	<	if ((s = task.status) < 0)
1816	<	return s;
1817	<	if ((q = ws[(i + origin) & m]) != null &&
1818	<	(n = q.queueSize()) > 0) {
1819	<	signalWork(q, n);
1820	<	if ((int)(ctl >> AC_SHIFT) >= 0)
1810	>	private void helpSignal(ForkJoinTask<?> task, int origin) {
1811	>	WorkQueue[] ws; WorkQueue w; Thread p; long c; int m, u, e, i, s;
1812	>	if (task != null && task.status >= 0 &&
1813	>	(u = (int)(ctl >>> 32)) < 0 && (u >> UAC_SHIFT) < 0 &&
1814	>	(ws = workQueues) != null && (m = ws.length - 1) >= 0) {
1815	>	outer: for (int k = origin, j = m; j >= 0; --j) {
1816	>	WorkQueue q = ws[k++ & m];
1817	>	for (int n = m;;) { // limit to at most m signals
1818	>	if (task.status < 0)
1819	>	break outer;
1820	>	if (q == null ||
1821	>	((s = -q.base + q.top) <= n && (n = s) <= 0))
1822		break;
1823	+	if ((u = (int)((c = ctl) >>> 32)) >= 0 ||
1824	+	(e = (int)c) <= 0 || m < (i = e & SMASK) ||
1825	+	(w = ws[i]) == null)
1826	+	break outer;
1827	+	long nc = (((long)(w.nextWait & E_MASK)) |
1828	+	((long)(u + UAC_UNIT) << 32));
1829	+	if (w.eventCount == (e | INT_SIGN) &&
1830	+	U.compareAndSwapLong(this, CTL, c, nc)) {
1831	+	w.eventCount = (e + E_SEQ) & E_MASK;
1832	+	if ((p = w.parker) != null)
1833	+	U.unpark(p);
1834	+	if (--n <= 0)
1835	+	break;
1836	+	}
1837	+	}
1838	+	}
1839	+	}
1840	+	}
1841	+
1842	+	/**
1843	+	* Signals other workers if tasks are present in hinted queue.
1844	+	*
1845	+	* @param caller the worker with the hint
1846	+	*/
1847	+	private void helpSignalHint(WorkQueue caller) {
1848	+	WorkQueue[] ws; WorkQueue q, w; Thread p; long c; int h, m, u, e, i, s;
1849	+	if (caller != null && (h = caller.hint) >= 0) {
1850	+	caller.hint = -1;
1851	+	if ((u = (int)(ctl >>> 32)) < 0 && (u >> UAC_SHIFT) < 0 &&
1852	+	(ws = workQueues) != null && (m = ws.length - 1) >= 0 &&
1853	+	(q = ws[h & m]) != null) {
1854	+	for (int n = 2;;) { // limit to at most 2 signals
1855	+	int idleCount = (caller.eventCount < 0) ? 0 : -1;
1856	+	if (((s = idleCount - q.base + q.top) <= n &&
1857	+	(n = s) <= 0) ||
1858	+	(u = (int)((c = ctl) >>> 32)) >= 0 ||
1859	+	(e = (int)c) <= 0 || m < (i = e & SMASK) ||
1860	+	(w = ws[i]) == null)
1861	+	break;
1862	+	long nc = (((long)(w.nextWait & E_MASK)) |
1863	+	((long)(u + UAC_UNIT) << 32));
1864	+	if (w.eventCount == (e | INT_SIGN) &&
1865	+	U.compareAndSwapLong(this, CTL, c, nc)) {
1866	+	w.hint = h;
1867	+	w.eventCount = (e + E_SEQ) & E_MASK;
1868	+	if ((p = w.parker) != null)
1869	+	U.unpark(p);
1870	+	if (--n <= 0)
1871	+	break;
1872	+	}
1873		}
1874		}
1875		}
1762	–	return 0;
1876		}
1877
1878		/**
#	Line 1793 | Line 1906 | public class ForkJoinPool extends Abstra
1906		}
1907		if ((ws = workQueues) == null || (m = ws.length - 1) <= 0)
1908		break restart;              // shutting down
1909	<	if ((v = ws[h = (j.stealHint | 1) & m]) == null ||
1909	>	if ((v = ws[h = (j.hint | 1) & m]) == null ||
1910		v.currentSteal != subtask) {
1911		for (int origin = h;;) {    // find stealer
1912		if (((h = (h + 2) & m) & 15) == 1 &&
#	Line 1801 | Line 1914 | public class ForkJoinPool extends Abstra
1914		continue restart;   // occasional staleness check
1915		if ((v = ws[h]) != null &&
1916		v.currentSteal == subtask) {
1917	<	j.stealHint = h;    // save hint
1917	>	j.hint = h;        // save hint
1918		break;
1919		}
1920		if (h == origin)
#	Line 1850 | Line 1963 | public class ForkJoinPool extends Abstra
1963
1964		/**
1965		* Analog of tryHelpStealer for CountedCompleters. Tries to steal
1966	<	* and run tasks within the target's computation
1966	>	* and run tasks within the target's computation.
1967		*
1968		* @param task the task to join
1969		* @param mode if shared, exit upon completing any task
#	Line 1858 | Line 1971 | public class ForkJoinPool extends Abstra
1971		*
1972		*/
1973		private int helpComplete(ForkJoinTask<?> task, int mode) {
1974	<	WorkQueue[] ws; WorkQueue q; int m, n, s;
1974	>	WorkQueue[] ws; WorkQueue q; int m, n, s, u;
1975		if (task != null && (ws = workQueues) != null &&
1976		(m = ws.length - 1) >= 0) {
1977		for (int j = 1, origin = j;;) {
#	Line 1866 | Line 1979 | public class ForkJoinPool extends Abstra
1979		return s;
1980		if ((q = ws[j & m]) != null && q.pollAndExecCC(task)) {
1981		origin = j;
1982	<	if (mode == SHARED_QUEUE && (int)(ctl >> AC_SHIFT) >= 0)
1982	>	if (mode == SHARED_QUEUE &&
1983	>	((u = (int)(ctl >>> 32)) >= 0 || (u >> UAC_SHIFT) >= 0))
1984		break;
1985		}
1986		else if ((j = (j + 2) & m) == origin)
#	Line 1884 | Line 1998 | public class ForkJoinPool extends Abstra
1998		* may become starved.
1999		*/
2000		final boolean tryCompensate() {
2001	<	int pc = parallelism, e, u, i, tc; long c;
2001	>	int pc = config & SMASK, e, i, tc; long c;
2002		WorkQueue[] ws; WorkQueue w; Thread p;
2003	<	if ((e = (int)(c = ctl)) >= 0 && (ws = workQueues) != null) {
2003	>	if ((ws = workQueues) != null && (e = (int)(c = ctl)) >= 0) {
2004		if (e != 0 && (i = e & SMASK) < ws.length &&
2005		(w = ws[i]) != null && w.eventCount == (e | INT_SIGN)) {
2006		long nc = ((long)(w.nextWait & E_MASK) |
#	Line 1898 | Line 2012 | public class ForkJoinPool extends Abstra
2012		return true;   // replace with idle worker
2013		}
2014		}
2015	<	else if ((short)((u = (int)(c >>> 32)) >>> UTC_SHIFT) >= 0 &&
2016	<	(u >> UAC_SHIFT) + pc > 1) {
2015	>	else if ((tc = (short)(c >>> TC_SHIFT)) >= 0 &&
2016	>	(int)(c >> AC_SHIFT) + pc > 1) {
2017		long nc = ((c - AC_UNIT) & AC_MASK) | (c & ~AC_MASK);
2018		if (U.compareAndSwapLong(this, CTL, c, nc))
2019	<	return true;    // no compensation
2019	>	return true;   // no compensation
2020		}
2021	<	else if ((tc = u + pc) < MAX_CAP) {
2021	>	else if (tc + pc < MAX_CAP) {
2022		long nc = ((c + TC_UNIT) & TC_MASK) | (c & ~TC_MASK);
2023		if (U.compareAndSwapLong(this, CTL, c, nc)) {
2024	+	ForkJoinWorkerThreadFactory fac;
2025		Throwable ex = null;
2026		ForkJoinWorkerThread wt = null;
2027		try {
1913	–	ForkJoinWorkerThreadFactory fac;
2028		if ((fac = factory) != null &&
2029		(wt = fac.newThread(this)) != null) {
2030		wt.start();
#	Line 1919 | Line 2033 | public class ForkJoinPool extends Abstra
2033		} catch (Throwable rex) {
2034		ex = rex;
2035		}
2036	<	deregisterWorker(wt, ex); // adjust counts etc
2036	>	deregisterWorker(wt, ex); // clean up and return false
2037		}
2038		}
2039		}
#	Line 1938 | Line 2052 | public class ForkJoinPool extends Abstra
2052		if (joiner != null && task != null && (s = task.status) >= 0) {
2053		ForkJoinTask<?> prevJoin = joiner.currentJoin;
2054		joiner.currentJoin = task;
2055	<	do {} while ((s = task.status) >= 0 &&
1942	<	joiner.queueSize() > 0 &&
2055	>	do {} while ((s = task.status) >= 0 && !joiner.isEmpty() &&
2056		joiner.tryRemoveAndExec(task)); // process local tasks
2057	<	if (s >= 0 && (s = task.status) >= 0 &&
2058	<	(s = helpSignal(task, joiner.poolIndex)) >= 0 &&
2059	<	(task instanceof CountedCompleter))
2060	<	s = helpComplete(task, LIFO_QUEUE);
2057	>	if (s >= 0 && (s = task.status) >= 0) {
2058	>	helpSignal(task, joiner.poolIndex);
2059	>	if ((s = task.status) >= 0 &&
2060	>	(task instanceof CountedCompleter))
2061	>	s = helpComplete(task, LIFO_QUEUE);
2062	>	}
2063		while (s >= 0 && (s = task.status) >= 0) {
2064	<	if ((joiner.queueSize() > 0 ||           // try helping
2064	>	if ((!joiner.isEmpty() ||           // try helping
2065		(s = tryHelpStealer(joiner, task)) == 0) &&
2066	<	(s = task.status) >= 0 && tryCompensate()) {
2067	<	if (task.trySetSignal() && (s = task.status) >= 0) {
2068	<	synchronized (task) {
2069	<	if (task.status >= 0) {
2070	<	try {                // see ForkJoinTask
2071	<	task.wait();     //  for explanation
2072	<	} catch (InterruptedException ie) {
2066	>	(s = task.status) >= 0) {
2067	>	helpSignal(task, joiner.poolIndex);
2068	>	if ((s = task.status) >= 0 && tryCompensate()) {
2069	>	if (task.trySetSignal() && (s = task.status) >= 0) {
2070	>	synchronized (task) {
2071	>	if (task.status >= 0) {
2072	>	try {                // see ForkJoinTask
2073	>	task.wait();     //  for explanation
2074	>	} catch (InterruptedException ie) {
2075	>	}
2076		}
2077	+	else
2078	+	task.notifyAll();
2079		}
1960	–	else
1961	–	task.notifyAll();
2080		}
2081	+	long c;                          // re-activate
2082	+	do {} while (!U.compareAndSwapLong
2083	+	(this, CTL, c = ctl, c + AC_UNIT));
2084		}
1964	–	long c;                          // re-activate
1965	–	do {} while (!U.compareAndSwapLong
1966	–	(this, CTL, c = ctl, c + AC_UNIT));
2085		}
2086		}
2087		joiner.currentJoin = prevJoin;
#	Line 1984 | Line 2102 | public class ForkJoinPool extends Abstra
2102		if (joiner != null && task != null && (s = task.status) >= 0) {
2103		ForkJoinTask<?> prevJoin = joiner.currentJoin;
2104		joiner.currentJoin = task;
2105	<	do {} while ((s = task.status) >= 0 &&
1988	<	joiner.queueSize() > 0 &&
2105	>	do {} while ((s = task.status) >= 0 && !joiner.isEmpty() &&
2106		joiner.tryRemoveAndExec(task));
2107	<	if (s >= 0 && (s = task.status) >= 0 &&
2108	<	(s = helpSignal(task, joiner.poolIndex)) >= 0 &&
2109	<	(task instanceof CountedCompleter))
2110	<	s = helpComplete(task, LIFO_QUEUE);
2111	<	if (s >= 0 && joiner.queueSize() == 0) {
2107	>	if (s >= 0 && (s = task.status) >= 0) {
2108	>	helpSignal(task, joiner.poolIndex);
2109	>	if ((s = task.status) >= 0 &&
2110	>	(task instanceof CountedCompleter))
2111	>	s = helpComplete(task, LIFO_QUEUE);
2112	>	}
2113	>	if (s >= 0 && joiner.isEmpty()) {
2114		do {} while (task.status >= 0 &&
2115		tryHelpStealer(joiner, task) > 0);
2116		}
#	Line 2007 | Line 2126 | public class ForkJoinPool extends Abstra
2126		* @param r a (random) seed for scanning
2127		*/
2128		private WorkQueue findNonEmptyStealQueue(int r) {
2010	–	int step = (r >>> 16) | 1;
2129		for (WorkQueue[] ws;;) {
2130	<	int ps = plock, m;
2130	>	int ps = plock, m, n;
2131		if ((ws = workQueues) == null || (m = ws.length - 1) < 1)
2132		return null;
2133	<	for (int j = (m + 1) << 2; ; r += step) {
2134	<	WorkQueue q = ws[((r << 1) | 1) & m];
2135	<	if (q != null && q.queueSize() > 0)
2133	>	for (int j = (m + 1) << 2; ;) {
2134	>	WorkQueue q = ws[(((r + j) << 1) | 1) & m];
2135	>	if (q != null && (n = q.base - q.top) < 0) {
2136	>	if (n < -1)
2137	>	signalWork(q);
2138		return q;
2139	+	}
2140		else if (--j < 0) {
2141		if (plock == ps)
2142		return null;
#	Line 2058 | Line 2179 | public class ForkJoinPool extends Abstra
2179		}
2180		else
2181		c = ctl;        // re-increment on exit
2182	<	if ((int)(c >> AC_SHIFT) + parallelism == 0) {
2182	>	if ((int)(c >> AC_SHIFT) + (config & SMASK) == 0) {
2183		do {} while (!U.compareAndSwapLong
2184		(this, CTL, c = ctl, c + AC_UNIT));
2185		break;
#	Line 2133 | Line 2254 | public class ForkJoinPool extends Abstra
2254		static int getSurplusQueuedTaskCount() {
2255		Thread t; ForkJoinWorkerThread wt; ForkJoinPool pool; WorkQueue q;
2256		if (((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)) {
2257	<	int b = (q = (wt = (ForkJoinWorkerThread)t).workQueue).base;
2258	<	int p = (pool = wt.pool).parallelism;
2257	>	int p = (pool = (wt = (ForkJoinWorkerThread)t).pool).config & SMASK;
2258	>	int n = (q = wt.workQueue).top - q.base;
2259		int a = (int)(pool.ctl >> AC_SHIFT) + p;
2260	<	return q.top - b - (a > (p >>>= 1) ? 0 :
2261	<	a > (p >>>= 1) ? 1 :
2262	<	a > (p >>>= 1) ? 2 :
2263	<	a > (p >>>= 1) ? 4 :
2264	<	8);
2260	>	return n - (a > (p >>>= 1) ? 0 :
2261	>	a > (p >>>= 1) ? 1 :
2262	>	a > (p >>>= 1) ? 2 :
2263	>	a > (p >>>= 1) ? 4 :
2264	>	8);
2265		}
2266		return 0;
2267		}
#	Line 2166 | Line 2287 | public class ForkJoinPool extends Abstra
2287		return false;
2288		for (long c;;) {
2289		if (((c = ctl) & STOP_BIT) != 0) {      // already terminating
2290	<	if ((short)(c >>> TC_SHIFT) == -parallelism) {
2290	>	if ((short)(c >>> TC_SHIFT) == -(config & SMASK)) {
2291		synchronized (this) {
2292		notifyAll();                // signal when 0 workers
2293		}
#	Line 2185 | Line 2306 | public class ForkJoinPool extends Abstra
2306		releasePlock(nps);
2307		}
2308		if (!now) {                             // check if idle & no tasks
2309	<	if ((int)(c >> AC_SHIFT) != -parallelism ||
2309	>	if ((int)(c >> AC_SHIFT) != -(config & SMASK) ||
2310		hasQueuedSubmissions())
2311		return false;
2312		// Check for unqueued inactive workers. One pass suffices.
#	Line 2255 | Line 2376 | public class ForkJoinPool extends Abstra
2376		*/
2377		static boolean tryExternalUnpush(ForkJoinTask<?> t) {
2378		ForkJoinPool p; WorkQueue[] ws; WorkQueue q; Submitter z;
2379	<	ForkJoinTask<?>[] a;  int m, s; long j;
2380	<	if ((z = submitters.get()) != null &&
2379	>	ForkJoinTask<?>[] a;  int m, s;
2380	>	if (t != null &&
2381	>	(z = submitters.get()) != null &&
2382		(p = commonPool) != null &&
2383		(ws = p.workQueues) != null &&
2384		(m = ws.length - 1) >= 0 &&
2385		(q = ws[m & z.seed & SQMASK]) != null &&
2386		(s = q.top) != q.base &&
2387	<	(a = q.array) != null &&
2388	<	U.getObjectVolatile
2389	<	(a, j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE) == t &&
2390	<	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2391	<	if (q.array == a && q.top == s && // recheck
2392	<	U.compareAndSwapObject(a, j, t, null)) {
2393	<	q.top = s - 1;
2387	>	(a = q.array) != null) {
2388	>	long j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE;
2389	>	if (U.getObject(a, j) == t &&
2390	>	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2391	>	if (q.array == a && q.top == s && // recheck
2392	>	U.compareAndSwapObject(a, j, t, null)) {
2393	>	q.top = s - 1;
2394	>	q.qlock = 0;
2395	>	return true;
2396	>	}
2397		q.qlock = 0;
2273	–	return true;
2398		}
2275	–	q.qlock = 0;
2399		}
2400		return false;
2401		}
#	Line 2287 | Line 2410 | public class ForkJoinPool extends Abstra
2410		if (q != null && (a = q.array) != null && (m = (a.length - 1)) >= 0 &&
2411		root != null && root.status >= 0) {
2412		for (;;) {
2413	<	int s; Object o; CountedCompleter<?> task = null;
2413	>	int s, u; Object o; CountedCompleter<?> task = null;
2414		if ((s = q.top) - q.base > 0) {
2415		long j = ((m & (s - 1)) << ASHIFT) + ABASE;
2416		if ((o = U.getObject(a, j)) != null &&
#	Line 2305 | Line 2428 | public class ForkJoinPool extends Abstra
2428		}
2429		break;
2430		}
2431	<	} while((r = r.completer) != null);
2431	>	} while ((r = r.completer) != null);
2432		}
2433		}
2434		if (task != null)
2435		task.doExec();
2436	<	if (root.status < 0 || (int)(ctl >> AC_SHIFT) >= 0)
2436	>	if (root.status < 0 ||
2437	>	(u = (int)(ctl >>> 32)) >= 0 || (u >> UAC_SHIFT) >= 0)
2438		break;
2439		if (task == null) {
2440	<	if (helpSignal(root, q.poolIndex) >= 0)
2440	>	helpSignal(root, q.poolIndex);
2441	>	if (root.status >= 0)
2442		helpComplete(root, SHARED_QUEUE);
2443		break;
2444		}
#	Line 2328 | Line 2453 | public class ForkJoinPool extends Abstra
2453		static void externalHelpJoin(ForkJoinTask<?> t) {
2454		// Some hard-to-avoid overlap with tryExternalUnpush
2455		ForkJoinPool p; WorkQueue[] ws; WorkQueue q, w; Submitter z;
2456	<	ForkJoinTask<?>[] a;  int m, s, n; long j;
2457	<	if (t != null && t.status >= 0 &&
2456	>	ForkJoinTask<?>[] a;  int m, s, n;
2457	>	if (t != null &&
2458		(z = submitters.get()) != null &&
2459		(p = commonPool) != null &&
2460		(ws = p.workQueues) != null &&
2461		(m = ws.length - 1) >= 0 &&
2462		(q = ws[m & z.seed & SQMASK]) != null &&
2463		(a = q.array) != null) {
2464	<	if ((s = q.top) != q.base &&
2465	<	U.getObjectVolatile
2466	<	(a, j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE) == t &&
2467	<	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2468	<	if (q.array == a && q.top == s &&
2469	<	U.compareAndSwapObject(a, j, t, null)) {
2470	<	q.top = s - 1;
2471	<	q.qlock = 0;
2472	<	t.doExec();
2464	>	int am = a.length - 1;
2465	>	if ((s = q.top) != q.base) {
2466	>	long j = ((am & (s - 1)) << ASHIFT) + ABASE;
2467	>	if (U.getObject(a, j) == t &&
2468	>	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2469	>	if (q.array == a && q.top == s &&
2470	>	U.compareAndSwapObject(a, j, t, null)) {
2471	>	q.top = s - 1;
2472	>	q.qlock = 0;
2473	>	t.doExec();
2474	>	}
2475	>	else
2476	>	q.qlock = 0;
2477		}
2349	–	else
2350	–	q.qlock = 0;
2478		}
2479		if (t.status >= 0) {
2480		if (t instanceof CountedCompleter)
#	Line 2363 | Line 2490 | public class ForkJoinPool extends Abstra
2490		*/
2491		static void externalHelpQuiescePool() {
2492		ForkJoinPool p; ForkJoinTask<?> t; WorkQueue q; int b;
2366	–	int r = ThreadLocalRandom.current().nextInt();
2493		if ((p = commonPool) != null &&
2494	<	(q = p.findNonEmptyStealQueue(r)) != null &&
2494	>	(q = p.findNonEmptyStealQueue(1)) != null &&
2495		(b = q.base) - q.top < 0 &&
2496		(t = q.pollAt(b)) != null)
2497		t.doExec();
#	Line 2442 | Line 2568 | public class ForkJoinPool extends Abstra
2568		throw new NullPointerException();
2569		if (parallelism <= 0 || parallelism > MAX_CAP)
2570		throw new IllegalArgumentException();
2445	–	this.parallelism = parallelism;
2571		this.factory = factory;
2572		this.ueh = handler;
2573	<	this.localMode = asyncMode ? FIFO_QUEUE : LIFO_QUEUE;
2573	>	this.config = parallelism | (asyncMode ? (FIFO_QUEUE << 16) : 0);
2574		long np = (long)(-parallelism); // offset ctl counts
2575		this.ctl = ((np << AC_SHIFT) & AC_MASK) | ((np << TC_SHIFT) & TC_MASK);
2576		int pn = nextPoolId();
#	Line 2462 | Line 2587 | public class ForkJoinPool extends Abstra
2587		ForkJoinPool(int parallelism, long ctl,
2588		ForkJoinWorkerThreadFactory factory,
2589		Thread.UncaughtExceptionHandler handler) {
2590	<	this.parallelism = parallelism;
2590	>	this.config = parallelism;
2591		this.ctl = ctl;
2592		this.factory = factory;
2593		this.ueh = handler;
2469	–	this.localMode = LIFO_QUEUE;
2594		this.workerNamePrefix = "ForkJoinPool.commonPool-worker-";
2595		}
2596
#	Line 2476 | Line 2600 | public class ForkJoinPool extends Abstra
2600		* @return the common pool instance
2601		*/
2602		public static ForkJoinPool commonPool() {
2603	<	return commonPool; // cannot be null (if so, a static init error)
2603	>	// assert commonPool != null : "static init error";
2604	>	return commonPool;
2605		}
2606
2607		// Execution methods
#	Line 2648 | Line 2773 | public class ForkJoinPool extends Abstra
2773		* @return the targeted parallelism level of this pool
2774		*/
2775		public int getParallelism() {
2776	<	return parallelism;
2776	>	return config & SMASK;
2777		}
2778
2779		/**
#	Line 2669 | Line 2794 | public class ForkJoinPool extends Abstra
2794		* @return the number of worker threads
2795		*/
2796		public int getPoolSize() {
2797	<	return parallelism + (short)(ctl >>> TC_SHIFT);
2797	>	return (config & SMASK) + (short)(ctl >>> TC_SHIFT);
2798		}
2799
2800		/**
#	Line 2679 | Line 2804 | public class ForkJoinPool extends Abstra
2804		* @return {@code true} if this pool uses async mode
2805		*/
2806		public boolean getAsyncMode() {
2807	<	return localMode != 0;
2807	>	return (config >>> 16) == FIFO_QUEUE;
2808		}
2809
2810		/**
#	Line 2710 | Line 2835 | public class ForkJoinPool extends Abstra
2835		* @return the number of active threads
2836		*/
2837		public int getActiveThreadCount() {
2838	<	int r = parallelism + (int)(ctl >> AC_SHIFT);
2838	>	int r = (config & SMASK) + (int)(ctl >> AC_SHIFT);
2839		return (r <= 0) ? 0 : r; // suppress momentarily negative values
2840		}
2841
#	Line 2726 | Line 2851 | public class ForkJoinPool extends Abstra
2851		* @return {@code true} if all threads are currently idle
2852		*/
2853		public boolean isQuiescent() {
2854	<	return (int)(ctl >> AC_SHIFT) + parallelism == 0;
2854	>	return (int)(ctl >> AC_SHIFT) + (config & SMASK) == 0;
2855		}
2856
2857		/**
#	Line 2803 | Line 2928 | public class ForkJoinPool extends Abstra
2928		WorkQueue[] ws; WorkQueue w;
2929		if ((ws = workQueues) != null) {
2930		for (int i = 0; i < ws.length; i += 2) {
2931	<	if ((w = ws[i]) != null && w.queueSize() != 0)
2931	>	if ((w = ws[i]) != null && !w.isEmpty())
2932		return true;
2933		}
2934		}
#	Line 2889 | Line 3014 | public class ForkJoinPool extends Abstra
3014		}
3015		}
3016		}
3017	<	int pc = parallelism;
3017	>	int pc = (config & SMASK);
3018		int tc = pc + (short)(c >>> TC_SHIFT);
3019		int ac = pc + (int)(c >> AC_SHIFT);
3020		if (ac < 0) // ignore transient negative
#	Line 2962 | Line 3087 | public class ForkJoinPool extends Abstra
3087		public boolean isTerminated() {
3088		long c = ctl;
3089		return ((c & STOP_BIT) != 0L &&
3090	<	(short)(c >>> TC_SHIFT) == -parallelism);
3090	>	(short)(c >>> TC_SHIFT) == -(config & SMASK));
3091		}
3092
3093		/**
#	Line 2970 | Line 3095 | public class ForkJoinPool extends Abstra
3095		* commenced but not yet completed.  This method may be useful for
3096		* debugging. A return of {@code true} reported a sufficient
3097		* period after shutdown may indicate that submitted tasks have
3098	<	* ignored or suppressed interruption, or are waiting for IO,
3098	>	* ignored or suppressed interruption, or are waiting for I/O,
3099		* causing this executor not to properly terminate. (See the
3100		* advisory notes for class {@link ForkJoinTask} stating that
3101		* tasks should not normally entail blocking operations.  But if
#	Line 2981 | Line 3106 | public class ForkJoinPool extends Abstra
3106		public boolean isTerminating() {
3107		long c = ctl;
3108		return ((c & STOP_BIT) != 0L &&
3109	<	(short)(c >>> TC_SHIFT) != -parallelism);
3109	>	(short)(c >>> TC_SHIFT) != -(config & SMASK));
3110		}
3111
3112		/**
#	Line 3125 | Line 3250 | public class ForkJoinPool extends Abstra
3250		if (t instanceof ForkJoinWorkerThread) {
3251		ForkJoinPool p = ((ForkJoinWorkerThread)t).pool;
3252		while (!blocker.isReleasable()) { // variant of helpSignal
3253	<	WorkQueue[] ws; WorkQueue q; int m, n;
3253	>	WorkQueue[] ws; WorkQueue q; int m, u;
3254		if ((ws = p.workQueues) != null && (m = ws.length - 1) >= 0) {
3255		for (int i = 0; i <= m; ++i) {
3256		if (blocker.isReleasable())
3257		return;
3258	<	if ((q = ws[i]) != null && (n = q.queueSize()) > 0) {
3259	<	p.signalWork(q, n);
3260	<	if ((int)(p.ctl >> AC_SHIFT) >= 0)
3258	>	if ((q = ws[i]) != null && q.base - q.top < 0) {
3259	>	p.signalWork(q);
3260	>	if ((u = (int)(p.ctl >>> 32)) >= 0 ||
3261	>	(u >> UAC_SHIFT) >= 0)
3262		break;
3263		}
3264		}
#	Line 3178 | Line 3304 | public class ForkJoinPool extends Abstra
3304		private static final long QLOCK;
3305
3306		static {
3181	–	// Establish common pool parameters
3182	–	// TBD: limit or report ignored exceptions?
3183	–
3184	–	int par = 0;
3185	–	ForkJoinWorkerThreadFactory fac = null;
3186	–	Thread.UncaughtExceptionHandler handler = null;
3187	–	try {
3188	–	String pp = System.getProperty(propPrefix + "parallelism");
3189	–	String hp = System.getProperty(propPrefix + "exceptionHandler");
3190	–	String fp = System.getProperty(propPrefix + "threadFactory");
3191	–	if (fp != null)
3192	–	fac = ((ForkJoinWorkerThreadFactory)ClassLoader.
3193	–	getSystemClassLoader().loadClass(fp).newInstance());
3194	–	if (hp != null)
3195	–	handler = ((Thread.UncaughtExceptionHandler)ClassLoader.
3196	–	getSystemClassLoader().loadClass(hp).newInstance());
3197	–	if (pp != null)
3198	–	par = Integer.parseInt(pp);
3199	–	} catch(Exception ignore) {
3200	–	}
3201	–
3307		int s; // initialize field offsets for CAS etc
3308		try {
3309		U = getUnsafe();
#	Line 3227 | Line 3332 | public class ForkJoinPool extends Abstra
3332		if ((s & (s-1)) != 0)
3333		throw new Error("data type scale not a power of two");
3334
3335	+	submitters = new ThreadLocal<Submitter>();
3336	+	ForkJoinWorkerThreadFactory fac = defaultForkJoinWorkerThreadFactory =
3337	+	new DefaultForkJoinWorkerThreadFactory();
3338	+	modifyThreadPermission = new RuntimePermission("modifyThread");
3339	+
3340		/*
3341	<	* For extra caution, computations to set up pool state are
3342	<	* here; the constructor just assigns these values to fields.
3341	>	* Establish common pool parameters.  For extra caution,
3342	>	* computations to set up common pool state are here; the
3343	>	* constructor just assigns these values to fields.
3344		*/
3345	<	ForkJoinWorkerThreadFactory defaultFac =
3346	<	defaultForkJoinWorkerThreadFactory =
3347	<	new DefaultForkJoinWorkerThreadFactory();
3348	<	if (fac == null)
3349	<	fac = defaultFac;
3345	>
3346	>	int par = 0;
3347	>	Thread.UncaughtExceptionHandler handler = null;
3348	>	try {  // TBD: limit or report ignored exceptions?
3349	>	String pp = System.getProperty
3350	>	("java.util.concurrent.ForkJoinPool.common.parallelism");
3351	>	String hp = System.getProperty
3352	>	("java.util.concurrent.ForkJoinPool.common.exceptionHandler");
3353	>	String fp = System.getProperty
3354	>	("java.util.concurrent.ForkJoinPool.common.threadFactory");
3355	>	if (fp != null)
3356	>	fac = ((ForkJoinWorkerThreadFactory)ClassLoader.
3357	>	getSystemClassLoader().loadClass(fp).newInstance());
3358	>	if (hp != null)
3359	>	handler = ((Thread.UncaughtExceptionHandler)ClassLoader.
3360	>	getSystemClassLoader().loadClass(hp).newInstance());
3361	>	if (pp != null)
3362	>	par = Integer.parseInt(pp);
3363	>	} catch (Exception ignore) {
3364	>	}
3365	>
3366		if (par <= 0)
3367		par = Runtime.getRuntime().availableProcessors();
3368		if (par > MAX_CAP)
3369		par = MAX_CAP;
3370	+	commonPoolParallelism = par;
3371		long np = (long)(-par); // precompute initial ctl value
3372		long ct = ((np << AC_SHIFT) & AC_MASK) | ((np << TC_SHIFT) & TC_MASK);
3373
3246	–	commonPoolParallelism = par;
3374		commonPool = new ForkJoinPool(par, ct, fac, handler);
3248	–	modifyThreadPermission = new RuntimePermission("modifyThread");
3249	–	submitters = new ThreadLocal<Submitter>();
3375		}
3376
3377		/**

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