[ViewVC] Diff of: jsr166/jsr166/src/jsr166e/ForkJoinPool.java

Comparing jsr166/src/jsr166e/ForkJoinPool.java (file contents):
Revision 1.31 by dl, Sat Dec 15 22:15:47 2012 UTC vs.
Revision 1.60 by jsr166, Wed Jun 19 16:36:45 2013 UTC

#	Line 6 \| Line 6
6
7		package jsr166e;
8
9	+	import java.lang.Thread.UncaughtExceptionHandler;
10		import java.util.ArrayList;
11		import java.util.Arrays;
12		import java.util.Collection;
#	Line 17 \| Line 18 \| import java.util.concurrent.ExecutorServ
18		import java.util.concurrent.Future;
19		import java.util.concurrent.RejectedExecutionException;
20		import java.util.concurrent.RunnableFuture;
21	+	import java.util.concurrent.ThreadLocalRandom;
22		import java.util.concurrent.TimeUnit;
23
24		/**
#	Line 49 \| Line 51 \| import java.util.concurrent.TimeUnit;
51		* level; by default, equal to the number of available processors. The
52		* pool attempts to maintain enough active (or available) threads by
53		* dynamically adding, suspending, or resuming internal worker
54	<	* threads, even if some tasks are stalled waiting to join
55	<	* others. However, no such adjustments are guaranteed in the face of
56	<	* blocked I/O or other unmanaged synchronization. The nested {@link
54	>	* threads, even if some tasks are stalled waiting to join others.
55	>	* However, no such adjustments are guaranteed in the face of blocked
56	>	* I/O or other unmanaged synchronization. The nested {@link
57		* ManagedBlocker} interface enables extension of the kinds of
58		* synchronization accommodated.
59		*
#	Line 75 \| Line 77 \| import java.util.concurrent.TimeUnit;
77		* there is little difference among choice of methods.
78		*
79		* <table BORDER CELLPADDING=3 CELLSPACING=1>
80	+	* <caption>Summary of task execution methods</caption>
81		* <tr>
82		* <td></td>
83		* <td ALIGN=CENTER> <b>Call from non-fork/join clients</b></td>
84		* <td ALIGN=CENTER> <b>Call from within fork/join computations</b></td>
85		* </tr>
86		* <tr>
87	<	* <td> <b>Arrange async execution</td>
87	>	* <td> <b>Arrange async execution</b></td>
88		* <td> {@link #execute(ForkJoinTask)}</td>
89		* <td> {@link ForkJoinTask#fork}</td>
90		* </tr>
91		* <tr>
92	<	* <td> <b>Await and obtain result</td>
92	>	* <td> <b>Await and obtain result</b></td>
93		* <td> {@link #invoke(ForkJoinTask)}</td>
94		* <td> {@link ForkJoinTask#invoke}</td>
95		* </tr>
96		* <tr>
97	<	* <td> <b>Arrange exec and obtain Future</td>
97	>	* <td> <b>Arrange exec and obtain Future</b></td>
98		* <td> {@link #submit(ForkJoinTask)}</td>
99		* <td> {@link ForkJoinTask#fork} (ForkJoinTasks <em>are</em> Futures)</td>
100		* </tr>
101		* </table>
102		*
103		* <p>The common pool is by default constructed with default
104	<	* parameters, but these may be controlled by setting three {@link
105	<	* System#getProperty system properties} with prefix {@code
106	<	* java.util.concurrent.ForkJoinPool.common}: {@code parallelism} --
107	<	* an integer greater than zero, {@code threadFactory} -- the class
108	<	* name of a {@link ForkJoinWorkerThreadFactory}, and {@code
109	<	* exceptionHandler} -- the class name of a {@link
110	<	* java.lang.Thread.UncaughtExceptionHandler
111	<	* Thread.UncaughtExceptionHandler}. Upon any error in establishing
112	<	* these settings, default parameters are used.
104	>	* parameters, but these may be controlled by setting three
105	>	* {@linkplain System#getProperty system properties}:
106	>	* <ul>
107	>	* <li>{@code java.util.concurrent.ForkJoinPool.common.parallelism}
108	>	* - the parallelism level, a non-negative integer
109	>	* <li>{@code java.util.concurrent.ForkJoinPool.common.threadFactory}
110	>	* - the class name of a {@link ForkJoinWorkerThreadFactory}
111	>	* <li>{@code java.util.concurrent.ForkJoinPool.common.exceptionHandler}
112	>	* - the class name of a {@link UncaughtExceptionHandler}
113	>	* </ul>
114	>	* The system class loader is used to load these classes.
115	>	* Upon any error in establishing these settings, default parameters
116	>	* are used. It is possible to disable or limit the use of threads in
117	>	* the common pool by setting the parallelism property to zero, and/or
118	>	* using a factory that may return {@code null}.
119		*
120		* <p><b>Implementation notes</b>: This implementation restricts the
121		* maximum number of running threads to 32767. Attempts to create
#	Line 152 \| Line 161 \| public class ForkJoinPool extends Abstra
161		* (http://research.sun.com/scalable/pubs/index.html) and
162		* "Idempotent work stealing" by Michael, Saraswat, and Vechev,
163		* PPoPP 2009 (http://portal.acm.org/citation.cfm?id=1504186).
164	<	* The main differences ultimately stem from GC requirements that
165	<	* we null out taken slots as soon as we can, to maintain as small
166	<	* a footprint as possible even in programs generating huge
167	<	* numbers of tasks. To accomplish this, we shift the CAS
168	<	* arbitrating pop vs poll (steal) from being on the indices
169	<	* ("base" and "top") to the slots themselves. So, both a
170	<	* successful pop and poll mainly entail a CAS of a slot from
171	<	* non-null to null. Because we rely on CASes of references, we
172	<	* do not need tag bits on base or top. They are simple ints as
173	<	* used in any circular array-based queue (see for example
174	<	* ArrayDeque). Updates to the indices must still be ordered in a
175	<	* way that guarantees that top == base means the queue is empty,
176	<	* but otherwise may err on the side of possibly making the queue
177	<	* appear nonempty when a push, pop, or poll have not fully
178	<	* committed. Note that this means that the poll operation,
179	<	* considered individually, is not wait-free. One thief cannot
180	<	* successfully continue until another in-progress one (or, if
181	<	* previously empty, a push) completes. However, in the
182	<	* aggregate, we ensure at least probabilistic non-blockingness.
183	<	* If an attempted steal fails, a thief always chooses a different
184	<	* random victim target to try next. So, in order for one thief to
185	<	* progress, it suffices for any in-progress poll or new push on
186	<	* any empty queue to complete. (This is why we normally use
187	<	* method pollAt and its variants that try once at the apparent
188	<	* base index, else consider alternative actions, rather than
189	<	* method poll.)
164	>	* See also "Correct and Efficient Work-Stealing for Weak Memory
165	>	* Models" by Le, Pop, Cohen, and Nardelli, PPoPP 2013
166	>	* (http://www.di.ens.fr/~zappa/readings/ppopp13.pdf) for an
167	>	* analysis of memory ordering (atomic, volatile etc) issues. The
168	>	* main differences ultimately stem from GC requirements that we
169	>	* null out taken slots as soon as we can, to maintain as small a
170	>	* footprint as possible even in programs generating huge numbers
171	>	* of tasks. To accomplish this, we shift the CAS arbitrating pop
172	>	* vs poll (steal) from being on the indices ("base" and "top") to
173	>	* the slots themselves. So, both a successful pop and poll
174	>	* mainly entail a CAS of a slot from non-null to null. Because
175	>	* we rely on CASes of references, we do not need tag bits on base
176	>	* or top. They are simple ints as used in any circular
177	>	* array-based queue (see for example ArrayDeque). Updates to the
178	>	* indices must still be ordered in a way that guarantees that top
179	>	* == base means the queue is empty, but otherwise may err on the
180	>	* side of possibly making the queue appear nonempty when a push,
181	>	* pop, or poll have not fully committed. Note that this means
182	>	* that the poll operation, considered individually, is not
183	>	* wait-free. One thief cannot successfully continue until another
184	>	* in-progress one (or, if previously empty, a push) completes.
185	>	* However, in the aggregate, we ensure at least probabilistic
186	>	* non-blockingness. If an attempted steal fails, a thief always
187	>	* chooses a different random victim target to try next. So, in
188	>	* order for one thief to progress, it suffices for any
189	>	* in-progress poll or new push on any empty queue to
190	>	* complete. (This is why we normally use method pollAt and its
191	>	* variants that try once at the apparent base index, else
192	>	* consider alternative actions, rather than method poll.)
193		*
194		* This approach also enables support of a user mode in which local
195		* task processing is in FIFO, not LIFO order, simply by using
#	Line 196 \| Line 208 \| public class ForkJoinPool extends Abstra
208		* for work-stealing (this would contaminate lifo/fifo
209		* processing). Instead, we randomly associate submission queues
210		* with submitting threads, using a form of hashing. The
211	<	* ThreadLocal Submitter class contains a value initially used as
212	<	* a hash code for choosing existing queues, but may be randomly
213	<	* repositioned upon contention with other submitters. In
214	<	* essence, submitters act like workers except that they are
215	<	* restricted to executing local tasks that they submitted (or in
216	<	* the case of CountedCompleters, others with the same root task).
217	<	* However, because most shared/external queue operations are more
218	<	* expensive than internal, and because, at steady state, external
219	<	* submitters will compete for CPU with workers, ForkJoinTask.join
220	<	* and related methods disable them from repeatedly helping to
221	<	* process tasks if all workers are active. Insertion of tasks in
222	<	* shared mode requires a lock (mainly to protect in the case of
211	>	* Submitter probe value serves as a hash code for
212	>	* choosing existing queues, and may be randomly repositioned upon
213	>	* contention with other submitters. In essence, submitters act
214	>	* like workers except that they are restricted to executing local
215	>	* tasks that they submitted (or in the case of CountedCompleters,
216	>	* others with the same root task). However, because most
217	>	* shared/external queue operations are more expensive than
218	>	* internal, and because, at steady state, external submitters
219	>	* will compete for CPU with workers, ForkJoinTask.join and
220	>	* related methods disable them from repeatedly helping to process
221	>	* tasks if all workers are active. Insertion of tasks in shared
222	>	* mode requires a lock (mainly to protect in the case of
223		* resizing) but we use only a simple spinlock (using bits in
224		* field qlock), because submitters encountering a busy queue move
225		* on to try or create other queues -- they block only when
#	Line 297 \| Line 309 \| public class ForkJoinPool extends Abstra
309		* has not yet entered the wait queue. We solve this by requiring
310		* a full sweep of all workers (via repeated calls to method
311		* scan()) both before and after a newly waiting worker is added
312	<	* to the wait queue. During a rescan, the worker might release
313	<	* some other queued worker rather than itself, which has the same
314	<	* net effect. Because enqueued workers may actually be rescanning
315	<	* rather than waiting, we set and clear the "parker" field of
316	<	* WorkQueues to reduce unnecessary calls to unpark. (This
317	<	* requires a secondary recheck to avoid missed signals.) Note
318	<	* the unusual conventions about Thread.interrupts surrounding
319	<	* parking and other blocking: Because interrupts are used solely
320	<	* to alert threads to check termination, which is checked anyway
321	<	* upon blocking, we clear status (using Thread.interrupted)
322	<	* before any call to park, so that park does not immediately
311	<	* return due to status being set via some other unrelated call to
312	<	* interrupt in user code.
312	>	* to the wait queue. Because enqueued workers may actually be
313	>	* rescanning rather than waiting, we set and clear the "parker"
314	>	* field of WorkQueues to reduce unnecessary calls to unpark.
315	>	* (This requires a secondary recheck to avoid missed signals.)
316	>	* Note the unusual conventions about Thread.interrupts
317	>	* surrounding parking and other blocking: Because interrupts are
318	>	* used solely to alert threads to check termination, which is
319	>	* checked anyway upon blocking, we clear status (using
320	>	* Thread.interrupted) before any call to park, so that park does
321	>	* not immediately return due to status being set via some other
322	>	* unrelated call to interrupt in user code.
323		*
324		* Signalling. We create or wake up workers only when there
325		* appears to be at least one task they might be able to find and
326	<	* execute. However, many other threads may notice the same task
327	<	* and each signal to wake up a thread that might take it. So in
328	<	* general, pools will be over-signalled. When a submission is
329	<	* added or another worker adds a task to a queue that has fewer
330	<	* than two tasks, they signal waiting workers (or trigger
331	<	* creation of new ones if fewer than the given parallelism level
332	<	* -- signalWork), and may leave a hint to the unparked worker to
333	<	* 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
326	>	* execute. When a submission is added or another worker adds a
327	>	* task to a queue that has fewer than two tasks, they signal
328	>	* waiting workers (or trigger creation of new ones if fewer than
329	>	* the given parallelism level -- signalWork). These primary
330	>	* signals are buttressed by others whenever other threads remove
331	>	* a task from a queue and notice that there are other tasks there
332	>	* as well. So in general, pools will be over-signalled. On most
333	>	* platforms, signalling (unpark) overhead time is noticeably
334		* long, and the time between signalling a thread and it actually
335		* making progress can be very noticeably long, so it is worth
336		* offloading these delays from critical paths as much as
337	<	* possible.
337	>	* possible. Additionally, workers spin-down gradually, by staying
338	>	* alive so long as they see the ctl state changing. Similar
339	>	* stability-sensing techniques are also used before blocking in
340	>	* awaitJoin and helpComplete.
341		*
342		* Trimming workers. To release resources after periods of lack of
343		* use, a worker starting to wait when the pool is quiescent will
#	Line 440 \| Line 450 \| public class ForkJoinPool extends Abstra
450		* Common Pool
451		* ===========
452		*
453	<	* The static commonPool always exists after static
453	>	* The static common pool always exists after static
454		* initialization. Since it (or any other created pool) need
455		* never be used, we minimize initial construction overhead and
456		* footprint to the setup of about a dozen fields, with no nested
#	Line 448 \| Line 458 \| public class ForkJoinPool extends Abstra
458		* fullExternalPush during the first submission to the pool.
459		*
460		* When external threads submit to the common pool, they can
461	<	* perform some subtask processing (see externalHelpJoin and
462	<	* related methods). We do not need to record whether these
461	>	* perform subtask processing (see externalHelpJoin and related
462	>	* methods). This caller-helps policy makes it sensible to set
463	>	* common pool parallelism level to one (or more) less than the
464	>	* total number of available cores, or even zero for pure
465	>	* caller-runs. We do not need to record whether external
466		* submissions are to the common pool -- if not, externalHelpJoin
467		* returns quickly (at the most helping to signal some common pool
468		* workers). These submitters would otherwise be blocked waiting
#	Line 519 \| Line 532 \| public class ForkJoinPool extends Abstra
532		*
533		* @param pool the pool this thread works in
534		* @throws NullPointerException if the pool is null
535	+	* @return the new worker thread
536		*/
537		public ForkJoinWorkerThread newThread(ForkJoinPool pool);
538		}
#	Line 535 \| Line 549 \| public class ForkJoinPool extends Abstra
549		}
550
551		/**
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	–	/**
552		* Class for artificial tasks that are used to replace the target
553		* of local joins if they are removed from an interior queue slot
554		* in WorkQueue.tryRemoveAndExec. We don't need the proxy to
#	Line 613 \| Line 607 \| public class ForkJoinPool extends Abstra
607		* do not want multiple WorkQueue instances or multiple queue
608		* arrays sharing cache lines. (It would be best for queue objects
609		* and their arrays to share, but there is nothing available to
610	<	* help arrange that). Unfortunately, because they are recorded
611	<	* in a common array, WorkQueue instances are often moved to be
618	<	* adjacent by garbage collectors. To reduce impact, we use field
619	<	* padding that works OK on common platforms; this effectively
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
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.
610	>	* help arrange that). The @Contended annotation alerts JVMs to
611	>	* try to keep instances apart.
612		*/
613		static final class WorkQueue {
614		/**
#	Line 649 \| Line 634 \| public class ForkJoinPool extends Abstra
634		// Heuristic padding to ameliorate unfortunate memory placements
635		volatile long pad00, pad01, pad02, pad03, pad04, pad05, pad06;
636
652	–	int seed; // for random scanning; initialize nonzero
637		volatile int eventCount; // encoded inactivation count; < 0 if inactive
638		int nextWait; // encoded record of next event waiter
655	–	int hint; // steal or signal hint (index)
656	–	int poolIndex; // index of this queue in pool (or 0)
657	–	final int mode; // 0: lifo, > 0: fifo, < 0: shared
639		int nsteals; // number of steals
640	+	int hint; // steal index hint
641	+	short poolIndex; // index of this queue in pool
642	+	final short mode; // 0: lifo, > 0: fifo, < 0: shared
643		volatile int qlock; // 1: locked, -1: terminate; else 0
644		volatile int base; // index of next slot for poll
645		int top; // index of next slot for push
#	Line 673 \| Line 657 \| public class ForkJoinPool extends Abstra
657		int seed) {
658		this.pool = pool;
659		this.owner = owner;
660	<	this.mode = mode;
661	<	this.seed = seed;
660	>	this.mode = (short)mode;
661	>	this.hint = seed; // store initial seed for runWorker
662		// Place indices in the center of array (that is not yet allocated)
663		base = top = INITIAL_QUEUE_CAPACITY >>> 1;
664		}
#	Line 687 \| Line 671 \| public class ForkJoinPool extends Abstra
671		return (n >= 0) ? 0 : -n; // ignore transient negative
672		}
673
674	<	/**
674	>	/**
675		* Provides a more accurate estimate of whether this queue has
676		* any tasks than does queueSize, by checking whether a
677		* near-empty queue has at least one unclaimed task.
#	Line 708 \| Line 692 \| public class ForkJoinPool extends Abstra
692		* shared-queue version is embedded in method externalPush.)
693		*
694		* @param task the task. Caller must ensure non-null.
695	<	* @throw RejectedExecutionException if array cannot be resized
695	>	* @throws RejectedExecutionException if array cannot be resized
696		*/
697		final void push(ForkJoinTask<?> task) {
698		ForkJoinTask<?>[] a; ForkJoinPool p;
699	<	int s = top, m, n;
699	>	int s = top, n;
700		if ((a = array) != null) { // ignore if queue removed
701	<	int j = (((m = a.length - 1) & s) << ASHIFT) + ABASE;
702	<	U.putOrderedObject(a, j, task);
703	<	if ((n = (top = s + 1) - base) <= 2) {
704	<	if ((p = pool) != null)
721	<	p.signalWork(this);
722	<	}
701	>	int m = a.length - 1;
702	>	U.putOrderedObject(a, ((m & s) << ASHIFT) + ABASE, task);
703	>	if ((n = (top = s + 1) - base) <= 2)
704	>	(p = pool).signalWork(p.workQueues, this);
705		else if (n >= m)
706		growArray();
707		}
708		}
709
710	<	/**
710	>	/**
711		* Initializes or doubles the capacity of array. Call either
712		* by owner or with lock held -- it is OK for base, but not
713		* top, to move while resizings are in progress.
#	Line 783 \| Line 765 \| public class ForkJoinPool extends Abstra
765		if ((a = array) != null) {
766		int j = (((a.length - 1) & b) << ASHIFT) + ABASE;
767		if ((t = (ForkJoinTask<?>)U.getObjectVolatile(a, j)) != null &&
768	<	base == b &&
769	<	U.compareAndSwapObject(a, j, t, null)) {
788	<	base = b + 1;
768	>	base == b && U.compareAndSwapObject(a, j, t, null)) {
769	>	U.putOrderedInt(this, QBASE, b + 1);
770		return t;
771		}
772		}
#	Line 801 \| Line 782 \| public class ForkJoinPool extends Abstra
782		int j = (((a.length - 1) & b) << ASHIFT) + ABASE;
783		t = (ForkJoinTask<?>)U.getObjectVolatile(a, j);
784		if (t != null) {
785	<	if (base == b &&
786	<	U.compareAndSwapObject(a, j, t, null)) {
806	<	base = b + 1;
785	>	if (U.compareAndSwapObject(a, j, t, null)) {
786	>	U.putOrderedInt(this, QBASE, b + 1);
787		return t;
788		}
789		}
#	Line 860 \| Line 840 \| public class ForkJoinPool extends Abstra
840		ForkJoinTask.cancelIgnoringExceptions(t);
841		}
842
863	–	/**
864	–	* Computes next value for random probes. Scans don't require
865	–	* a very high quality generator, but also not a crummy one.
866	–	* Marsaglia xor-shift is cheap and works well enough. Note:
867	–	* This is manually inlined in its usages in ForkJoinPool to
868	–	* avoid writes inside busy scan loops.
869	–	*/
870	–	final int nextSeed() {
871	–	int r = seed;
872	–	r ^= r << 13;
873	–	r ^= r >>> 17;
874	–	return seed = r ^= r << 5;
875	–	}
876	–
843		// Specialized execution methods
844
845		/**
846	<	* Pops and runs tasks until empty.
846	>	* Polls and runs tasks until empty.
847		*/
848	<	private void popAndExecAll() {
849	<	// A bit faster than repeated pop calls
850	<	ForkJoinTask<?>[] a; int m, s; long j; ForkJoinTask<?> t;
885	<	while ((a = array) != null && (m = a.length - 1) >= 0 &&
886	<	(s = top - 1) - base >= 0 &&
887	<	(t = ((ForkJoinTask<?>)
888	<	U.getObject(a, j = ((m & s) << ASHIFT) + ABASE)))
889	<	!= null) {
890	<	if (U.compareAndSwapObject(a, j, t, null)) {
891	<	top = s;
892	<	t.doExec();
893	<	}
894	<	}
848	>	final void pollAndExecAll() {
849	>	for (ForkJoinTask<?> t; (t = poll()) != null;)
850	>	t.doExec();
851		}
852
853		/**
854	<	* Polls and runs tasks until empty.
854	>	* Executes a top-level task and any local tasks remaining
855	>	* after execution.
856		*/
857	<	private void pollAndExecAll() {
858	<	for (ForkJoinTask<?> t; (t = poll()) != null;)
859	<	t.doExec();
857	>	final void runTask(ForkJoinTask<?> task) {
858	>	if ((currentSteal = task) != null) {
859	>	task.doExec();
860	>	ForkJoinTask<?>[] a = array;
861	>	int md = mode;
862	>	++nsteals;
863	>	currentSteal = null;
864	>	if (md != 0)
865	>	pollAndExecAll();
866	>	else if (a != null) {
867	>	int s, m = a.length - 1;
868	>	while ((s = top - 1) - base >= 0) {
869	>	long i = ((m & s) << ASHIFT) + ABASE;
870	>	ForkJoinTask<?> t = (ForkJoinTask<?>)U.getObject(a, i);
871	>	if (t == null)
872	>	break;
873	>	if (U.compareAndSwapObject(a, i, t, null)) {
874	>	top = s;
875	>	t.doExec();
876	>	}
877	>	}
878	>	}
879	>	}
880		}
881
882		/**
#	Line 907 \| Line 884 \| public class ForkJoinPool extends Abstra
884		* or any other cancelled task. Returns (true) on any CAS
885		* or consistency check failure so caller can retry.
886		*
887	<	* @return false if no progress can be made, else true;
887	>	* @return false if no progress can be made, else true
888		*/
889		final boolean tryRemoveAndExec(ForkJoinTask<?> task) {
890	<	boolean stat = true, removed = false, empty = true;
890	>	boolean stat;
891		ForkJoinTask<?>[] a; int m, s, b, n;
892	<	if ((a = array) != null && (m = a.length - 1) >= 0 &&
892	>	if (task != null && (a = array) != null && (m = a.length - 1) >= 0 &&
893		(n = (s = top) - (b = base)) > 0) {
894	+	boolean removed = false, empty = true;
895	+	stat = true;
896		for (ForkJoinTask<?> t;;) { // traverse from s to b
897	<	int j = ((--s & m) << ASHIFT) + ABASE;
898	<	t = (ForkJoinTask<?>)U.getObjectVolatile(a, j);
897	>	long j = ((--s & m) << ASHIFT) + ABASE;
898	>	t = (ForkJoinTask<?>)U.getObject(a, j);
899		if (t == null) // inconsistent length
900		break;
901		else if (t == task) {
#	Line 944 \| Line 923 \| public class ForkJoinPool extends Abstra
923		break;
924		}
925		}
926	+	if (removed)
927	+	task.doExec();
928		}
929	<	if (removed)
930	<	task.doExec();
929	>	else
930	>	stat = false;
931		return stat;
932		}
933
934		/**
935	<	* Polls for and executes the given task or any other task in
936	<	* its CountedCompleter computation
935	>	* Tries to poll for and execute the given task or any other
936	>	* task in its CountedCompleter computation.
937		*/
938	<	final boolean pollAndExecCC(ForkJoinTask<?> root) {
939	<	ForkJoinTask<?>[] a; int b; Object o;
940	<	outer: while ((b = base) - top < 0 && (a = array) != null) {
938	>	final boolean pollAndExecCC(CountedCompleter<?> root) {
939	>	ForkJoinTask<?>[] a; int b; Object o; CountedCompleter<?> t, r;
940	>	if ((b = base) - top < 0 && (a = array) != null) {
941		long j = (((a.length - 1) & b) << ASHIFT) + ABASE;
942	<	if ((o = U.getObject(a, j)) == null \|\|
943	<	!(o instanceof CountedCompleter))
944	<	break;
945	<	for (CountedCompleter<?> t = (CountedCompleter<?>)o, r = t;;) {
946	<	if (r == root) {
947	<	if (base == b &&
948	<	U.compareAndSwapObject(a, j, t, null)) {
949	<	base = b + 1;
950	<	t.doExec();
942	>	if ((o = U.getObjectVolatile(a, j)) == null)
943	>	return true; // retry
944	>	if (o instanceof CountedCompleter) {
945	>	for (t = (CountedCompleter<?>)o, r = t;;) {
946	>	if (r == root) {
947	>	if (base == b &&
948	>	U.compareAndSwapObject(a, j, t, null)) {
949	>	U.putOrderedInt(this, QBASE, b + 1);
950	>	t.doExec();
951	>	}
952		return true;
953		}
954	<	else
955	<	break; // restart
954	>	else if ((r = r.completer) == null)
955	>	break; // not part of root computation
956		}
975	–	if ((r = r.completer) == null)
976	–	break outer; // not part of root computation
957		}
958		}
959		return false;
960		}
961
962		/**
963	<	* Executes a top-level task and any local tasks remaining
964	<	* after execution.
963	>	* Tries to pop and execute the given task or any other task
964	>	* in its CountedCompleter computation.
965		*/
966	<	final void runTask(ForkJoinTask<?> t) {
967	<	if (t != null) {
968	<	(currentSteal = t).doExec();
969	<	currentSteal = null;
970	<	if (base - top < 0) { // process remaining local tasks
971	<	if (mode == 0)
972	<	popAndExecAll();
973	<	else
974	<	pollAndExecAll();
966	>	final boolean externalPopAndExecCC(CountedCompleter<?> root) {
967	>	ForkJoinTask<?>[] a; int s; Object o; CountedCompleter<?> t, r;
968	>	if (base - (s = top) < 0 && (a = array) != null) {
969	>	long j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE;
970	>	if ((o = U.getObject(a, j)) instanceof CountedCompleter) {
971	>	for (t = (CountedCompleter<?>)o, r = t;;) {
972	>	if (r == root) {
973	>	if (U.compareAndSwapInt(this, QLOCK, 0, 1)) {
974	>	if (top == s && array == a &&
975	>	U.compareAndSwapObject(a, j, t, null)) {
976	>	top = s - 1;
977	>	qlock = 0;
978	>	t.doExec();
979	>	}
980	>	else
981	>	qlock = 0;
982	>	}
983	>	return true;
984	>	}
985	>	else if ((r = r.completer) == null)
986	>	break;
987	>	}
988		}
996	–	++nsteals;
997	–	hint = -1;
989		}
990	+	return false;
991		}
992
993		/**
994	<	* Executes a non-top-level (stolen) task.
994	>	* Internal version
995		*/
996	<	final void runSubtask(ForkJoinTask<?> t) {
997	<	if (t != null) {
998	<	ForkJoinTask<?> ps = currentSteal;
999	<	(currentSteal = t).doExec();
1000	<	currentSteal = ps;
996	>	final boolean internalPopAndExecCC(CountedCompleter<?> root) {
997	>	ForkJoinTask<?>[] a; int s; Object o; CountedCompleter<?> t, r;
998	>	if (base - (s = top) < 0 && (a = array) != null) {
999	>	long j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE;
1000	>	if ((o = U.getObject(a, j)) instanceof CountedCompleter) {
1001	>	for (t = (CountedCompleter<?>)o, r = t;;) {
1002	>	if (r == root) {
1003	>	if (U.compareAndSwapObject(a, j, t, null)) {
1004	>	top = s - 1;
1005	>	t.doExec();
1006	>	}
1007	>	return true;
1008	>	}
1009	>	else if ((r = r.completer) == null)
1010	>	break;
1011	>	}
1012	>	}
1013		}
1014	+	return false;
1015		}
1016
1017		/**
#	Line 1021 \| Line 1026 \| public class ForkJoinPool extends Abstra
1026		s != Thread.State.TIMED_WAITING);
1027		}
1028
1024	–	/**
1025	–	* If this owned and is not already interrupted, try to
1026	–	* interrupt and/or unpark, ignoring exceptions.
1027	–	*/
1028	–	final void interruptOwner() {
1029	–	Thread wt, p;
1030	–	if ((wt = owner) != null && !wt.isInterrupted()) {
1031	–	try {
1032	–	wt.interrupt();
1033	–	} catch (SecurityException ignore) {
1034	–	}
1035	–	}
1036	–	if ((p = parker) != null)
1037	–	U.unpark(p);
1038	–	}
1039	–
1029		// Unsafe mechanics
1030		private static final sun.misc.Unsafe U;
1031	+	private static final long QBASE;
1032		private static final long QLOCK;
1033		private static final int ABASE;
1034		private static final int ASHIFT;
1035		static {
1046	–	int s;
1036		try {
1037		U = getUnsafe();
1038		Class<?> k = WorkQueue.class;
1039		Class<?> ak = ForkJoinTask[].class;
1040	+	QBASE = U.objectFieldOffset
1041	+	(k.getDeclaredField("base"));
1042		QLOCK = U.objectFieldOffset
1043		(k.getDeclaredField("qlock"));
1044		ABASE = U.arrayBaseOffset(ak);
1045	<	s = U.arrayIndexScale(ak);
1045	>	int scale = U.arrayIndexScale(ak);
1046	>	if ((scale & (scale - 1)) != 0)
1047	>	throw new Error("data type scale not a power of two");
1048	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
1049		} catch (Exception e) {
1050		throw new Error(e);
1051		}
1058	–	if ((s & (s-1)) != 0)
1059	–	throw new Error("data type scale not a power of two");
1060	–	ASHIFT = 31 - Integer.numberOfLeadingZeros(s);
1052		}
1053		}
1054
1055		// static fields (initialized in static initializer below)
1056
1057		/**
1067	–	* Creates a new ForkJoinWorkerThread. This factory is used unless
1068	–	* overridden in ForkJoinPool constructors.
1069	–	*/
1070	–	public static final ForkJoinWorkerThreadFactory
1071	–	defaultForkJoinWorkerThreadFactory;
1072	–
1073	–	/**
1058		* Per-thread submission bookkeeping. Shared across all pools
1059		* to reduce ThreadLocal pollution and because random motion
1060		* to avoid contention in one pool is likely to hold for others.
#	Line 1080 \| Line 1064 \| public class ForkJoinPool extends Abstra
1064		static final ThreadLocal<Submitter> submitters;
1065
1066		/**
1067	+	* Creates a new ForkJoinWorkerThread. This factory is used unless
1068	+	* overridden in ForkJoinPool constructors.
1069	+	*/
1070	+	public static final ForkJoinWorkerThreadFactory
1071	+	defaultForkJoinWorkerThreadFactory;
1072	+
1073	+	/**
1074		* Permission required for callers of methods that may start or
1075		* kill threads.
1076		*/
#	Line 1091 \| Line 1082 \| public class ForkJoinPool extends Abstra
1082		* to paranoically avoid potential initialization circularities
1083		* as well as to simplify generated code.
1084		*/
1085	<	static final ForkJoinPool commonPool;
1085	>	static final ForkJoinPool common;
1086
1087		/**
1088	<	* Common pool parallelism. Must equal commonPool.parallelism.
1088	>	* Common pool parallelism. To allow simpler use and management
1089	>	* when common pool threads are disabled, we allow the underlying
1090	>	* common.parallelism field to be zero, but in that case still report
1091	>	* parallelism as 1 to reflect resulting caller-runs mechanics.
1092		*/
1093	<	static final int commonPoolParallelism;
1093	>	static final int commonParallelism;
1094
1095		/**
1096		* Sequence number for creating workerNamePrefix.
#	Line 1104 \| Line 1098 \| public class ForkJoinPool extends Abstra
1098		private static int poolNumberSequence;
1099
1100		/**
1101	<	* Return the next sequence number. We don't expect this to
1102	<	* ever contend so use simple builtin sync.
1101	>	* Returns the next sequence number. We don't expect this to
1102	>	* ever contend, so use simple builtin sync.
1103		*/
1104		private static final synchronized int nextPoolId() {
1105		return ++poolNumberSequence;
#	Line 1131 \| Line 1125 \| public class ForkJoinPool extends Abstra
1125		/**
1126		* Tolerance for idle timeouts, to cope with timer undershoots
1127		*/
1128	<	private static final long TIMEOUT_SLOP = 2000000L; // 20ms
1128	>	private static final long TIMEOUT_SLOP = 2000000L;
1129
1130		/**
1131		* The maximum stolen->joining link depth allowed in method
#	Line 1149 \| Line 1143 \| public class ForkJoinPool extends Abstra
1143		*/
1144		private static final int SEED_INCREMENT = 0x61c88647;
1145
1146	<	/**
1146	>	/*
1147		* Bits and masks for control variables
1148		*
1149		* Field ctl is a long packed with:
#	Line 1233 \| Line 1227 \| public class ForkJoinPool extends Abstra
1227		static final int FIFO_QUEUE = 1;
1228		static final int SHARED_QUEUE = -1;
1229
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 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	–
1230		// Heuristic padding to ameliorate unfortunate memory placements
1231		volatile long pad00, pad01, pad02, pad03, pad04, pad05, pad06;
1232
1233	+	// Instance fields
1234		volatile long stealCount; // collects worker counts
1235		volatile long ctl; // main pool control
1236		volatile int plock; // shutdown status and seqLock
1237		volatile int indexSeed; // worker/submitter index seed
1238	<	final int config; // mode and parallelism level
1238	>	final short parallelism; // parallelism level
1239	>	final short mode; // LIFO/FIFO
1240		WorkQueue[] workQueues; // main registry
1241		final ForkJoinWorkerThreadFactory factory;
1242	<	final Thread.UncaughtExceptionHandler ueh; // per-worker UEH
1242	>	final UncaughtExceptionHandler ueh; // per-worker UEH
1243		final String workerNamePrefix; // to create worker name string
1244
1245		volatile Object pad10, pad11, pad12, pad13, pad14, pad15, pad16, pad17;
1246		volatile Object pad18, pad19, pad1a, pad1b;
1247
1248	<	/*
1248	>	/**
1249		* Acquires the plock lock to protect worker array and related
1250		* updates. This method is called only if an initial CAS on plock
1251	<	* fails. This acts as a spinLock for normal cases, but falls back
1251	>	* fails. This acts as a spinlock for normal cases, but falls back
1252		* to builtin monitor to block when (rarely) needed. This would be
1253		* a terrible idea for a highly contended lock, but works fine as
1254	<	* a more conservative alternative to a pure spinlock. See
1272	<	* internal ConcurrentHashMap documentation for further
1273	<	* explanation of nearly the same construction.
1254	>	* a more conservative alternative to a pure spinlock.
1255		*/
1256		private int acquirePlock() {
1257	<	int spins = PL_SPINS, r = 0, ps, nps;
1257	>	int spins = PL_SPINS, ps, nps;
1258		for (;;) {
1259		if (((ps = plock) & PL_LOCK) == 0 &&
1260		U.compareAndSwapInt(this, PLOCK, ps, nps = ps + PL_LOCK))
1261		return nps;
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	–	}
1262		else if (spins >= 0) {
1263	<	r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
1293	<	if (r >= 0)
1263	>	if (ThreadLocalRandom.current().nextInt() >= 0)
1264		--spins;
1265		}
1266		else if (U.compareAndSwapInt(this, PLOCK, ps, ps \| PL_SIGNAL)) {
#	Line 1322 \| Line 1292 \| public class ForkJoinPool extends Abstra
1292		}
1293
1294		/**
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	–	/**
1295		* Tries to create and start one worker if fewer than target
1296		* parallelism level exist. Adjusts counts etc on failure.
1297		*/
1298		private void tryAddWorker() {
1299	<	long c; int u;
1299	>	long c; int u, e;
1300		while ((u = (int)((c = ctl) >>> 32)) < 0 &&
1301	<	(u & SHORT_SIGN) != 0 && (int)c == 0) {
1302	<	long nc = (long)(((u + UTC_UNIT) & UTC_MASK) \|
1303	<	((u + UAC_UNIT) & UAC_MASK)) << 32;
1301	>	(u & SHORT_SIGN) != 0 && (e = (int)c) >= 0) {
1302	>	long nc = ((long)(((u + UTC_UNIT) & UTC_MASK) \|
1303	>	((u + UAC_UNIT) & UAC_MASK)) << 32) \| (long)e;
1304		if (U.compareAndSwapLong(this, CTL, c, nc)) {
1305		ForkJoinWorkerThreadFactory fac;
1306		Throwable ex = null;
#	Line 1374 \| Line 1311 \| public class ForkJoinPool extends Abstra
1311		wt.start();
1312		break;
1313		}
1314	<	} catch (Throwable e) {
1315	<	ex = e;
1314	>	} catch (Throwable rex) {
1315	>	ex = rex;
1316		}
1317		deregisterWorker(wt, ex);
1318		break;
#	Line 1396 \| Line 1333 \| public class ForkJoinPool extends Abstra
1333		* @return the worker's queue
1334		*/
1335		final WorkQueue registerWorker(ForkJoinWorkerThread wt) {
1336	<	Thread.UncaughtExceptionHandler handler; WorkQueue[] ws; int s, ps;
1336	>	UncaughtExceptionHandler handler; WorkQueue[] ws; int s, ps;
1337		wt.setDaemon(true);
1338		if ((handler = ueh) != null)
1339		wt.setUncaughtExceptionHandler(handler);
1340		do {} while (!U.compareAndSwapInt(this, INDEXSEED, s = indexSeed,
1341		s += SEED_INCREMENT) \|\|
1342		s == 0); // skip 0
1343	<	WorkQueue w = new WorkQueue(this, wt, config >>> 16, s);
1343	>	WorkQueue w = new WorkQueue(this, wt, mode, s);
1344		if (((ps = plock) & PL_LOCK) != 0 \|\|
1345		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1346		ps = acquirePlock();
#	Line 1423 \| Line 1360 \| public class ForkJoinPool extends Abstra
1360		}
1361		}
1362		}
1363	<	w.eventCount = w.poolIndex = r; // volatile write orders
1363	>	w.poolIndex = (short)r;
1364	>	w.eventCount = r; // volatile write orders
1365		ws[r] = w;
1366		}
1367		} finally {
1368		if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1369		releasePlock(nps);
1370		}
1371	<	wt.setName(workerNamePrefix.concat(Integer.toString(w.poolIndex)));
1371	>	wt.setName(workerNamePrefix.concat(Integer.toString(w.poolIndex >>> 1)));
1372		return w;
1373		}
1374
#	Line 1440 \| Line 1378 \| public class ForkJoinPool extends Abstra
1378		* array, and adjusts counts. If pool is shutting down, tries to
1379		* complete termination.
1380		*
1381	<	* @param wt the worker thread or null if construction failed
1381	>	* @param wt the worker thread, or null if construction failed
1382		* @param ex the exception causing failure, or null if none
1383		*/
1384		final void deregisterWorker(ForkJoinWorkerThread wt, Throwable ex) {
1385		WorkQueue w = null;
1386		if (wt != null && (w = wt.workQueue) != null) {
1387	<	int ps;
1387	>	int ps; long sc;
1388		w.qlock = -1; // ensure set
1451	–	long ns = w.nsteals, sc; // collect steal count
1389		do {} while (!U.compareAndSwapLong(this, STEALCOUNT,
1390	<	sc = stealCount, sc + ns));
1390	>	sc = stealCount,
1391	>	sc + w.nsteals));
1392		if (((ps = plock) & PL_LOCK) != 0 \|\|
1393		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1394		ps = acquirePlock();
#	Line 1466 \| Line 1404 \| public class ForkJoinPool extends Abstra
1404		}
1405		}
1406
1407	<	long c; // adjust ctl counts
1407	>	long c; // adjust ctl counts
1408		do {} while (!U.compareAndSwapLong
1409		(this, CTL, c = ctl, (((c - AC_UNIT) & AC_MASK) \|
1410		((c - TC_UNIT) & TC_MASK) \|
1411		(c & ~(AC_MASK\|TC_MASK)))));
1412
1413		if (!tryTerminate(false, false) && w != null && w.array != null) {
1414	<	w.cancelAll(); // cancel remaining tasks
1415	<	int e, u, i, n; WorkQueue[] ws; WorkQueue v; Thread p;
1416	<	while ((u = (int)((c = ctl) >>> 32)) < 0) {
1417	<	if ((e = (int)c) > 0) { // activate or create replacement
1418	<	if ((ws = workQueues) != null &&
1419	<	ws.length > (i = e & SMASK) &&
1420	<	(v = ws[i]) != null && v.eventCount == (e \| INT_SIGN)) {
1421	<	long nc = (((long)(v.nextWait & E_MASK)) \|
1422	<	((long)(u + UAC_UNIT) << 32));
1423	<	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1424	<	v.eventCount = (e + E_SEQ) & E_MASK;
1425	<	if ((p = v.parker) != null)
1426	<	U.unpark(p);
1427	<	break;
1428	<	}
1429	<	}
1492	<	else
1414	>	w.cancelAll(); // cancel remaining tasks
1415	>	WorkQueue[] ws; WorkQueue v; Thread p; int u, i, e;
1416	>	while ((u = (int)((c = ctl) >>> 32)) < 0 && (e = (int)c) >= 0) {
1417	>	if (e > 0) { // activate or create replacement
1418	>	if ((ws = workQueues) == null \|\|
1419	>	(i = e & SMASK) >= ws.length \|\|
1420	>	(v = ws[i]) == null)
1421	>	break;
1422	>	long nc = (((long)(v.nextWait & E_MASK)) \|
1423	>	((long)(u + UAC_UNIT) << 32));
1424	>	if (v.eventCount != (e \| INT_SIGN))
1425	>	break;
1426	>	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1427	>	v.eventCount = (e + E_SEQ) & E_MASK;
1428	>	if ((p = v.parker) != null)
1429	>	U.unpark(p);
1430		break;
1431	+	}
1432		}
1433		else {
1434		if ((short)u < 0)
#	Line 1508 \| Line 1446 \| public class ForkJoinPool extends Abstra
1446		// Submissions
1447
1448		/**
1449	+	* Per-thread records for threads that submit to pools. Currently
1450	+	* holds only pseudo-random seed / index that is used to choose
1451	+	* submission queues in method externalPush. In the future, this may
1452	+	* also incorporate a means to implement different task rejection
1453	+	* and resubmission policies.
1454	+	*
1455	+	* Seeds for submitters and workers/workQueues work in basically
1456	+	* the same way but are initialized and updated using slightly
1457	+	* different mechanics. Both are initialized using the same
1458	+	* approach as in class ThreadLocal, where successive values are
1459	+	* unlikely to collide with previous values. Seeds are then
1460	+	* randomly modified upon collisions using xorshifts, which
1461	+	* requires a non-zero seed.
1462	+	*/
1463	+	static final class Submitter {
1464	+	int seed;
1465	+	Submitter(int s) { seed = s; }
1466	+	}
1467	+
1468	+	/**
1469		* Unless shutting down, adds the given task to a submission queue
1470		* at submitter's current queue index (modulo submission
1471		* range). Only the most common path is directly handled in this
#	Line 1516 \| Line 1474 \| public class ForkJoinPool extends Abstra
1474		* @param task the task. Caller must ensure non-null.
1475		*/
1476		final void externalPush(ForkJoinTask<?> task) {
1477	<	WorkQueue[] ws; WorkQueue q; Submitter z; int m; ForkJoinTask<?>[] a;
1478	<	if ((z = submitters.get()) != null && plock > 0 &&
1479	<	(ws = workQueues) != null && (m = (ws.length - 1)) >= 0 &&
1480	<	(q = ws[m & z.seed & SQMASK]) != null &&
1477	>	Submitter z = submitters.get();
1478	>	WorkQueue q; int r, m, s, n, am; ForkJoinTask<?>[] a;
1479	>	int ps = plock;
1480	>	WorkQueue[] ws = workQueues;
1481	>	if (z != null && ps > 0 && ws != null && (m = (ws.length - 1)) >= 0 &&
1482	>	(q = ws[m & (r = z.seed) & SQMASK]) != null && r != 0 &&
1483		U.compareAndSwapInt(q, QLOCK, 0, 1)) { // lock
1484	<	int b = q.base, s = q.top, n, an;
1485	<	if ((a = q.array) != null && (an = a.length) > (n = s + 1 - b)) {
1486	<	int j = (((an - 1) & s) << ASHIFT) + ABASE;
1484	>	if ((a = q.array) != null &&
1485	>	(am = a.length - 1) > (n = (s = q.top) - q.base)) {
1486	>	int j = ((am & s) << ASHIFT) + ABASE;
1487		U.putOrderedObject(a, j, task);
1488		q.top = s + 1; // push on to deque
1489		q.qlock = 0;
1490	<	if (n <= 2)
1491	<	signalWork(q);
1490	>	if (n <= 1)
1491	>	signalWork(ws, q);
1492		return;
1493		}
1494		q.qlock = 0;
#	Line 1539 \| Line 1499 \| public class ForkJoinPool extends Abstra
1499		/**
1500		* Full version of externalPush. This method is called, among
1501		* other times, upon the first submission of the first task to the
1502	<	* pool, so must perform secondary initialization (via
1503	<	* initWorkers). It also detects first submission by an external
1504	<	* thread by looking up its ThreadLocal, and creates a new shared
1505	<	* queue if the one at index if empty or contended. The plock lock
1506	<	* body must be exception-free (so no try/finally) so we
1507	<	* optimistically allocate new queues outside the lock and throw
1508	<	* them away if (very rarely) not needed.
1502	>	* pool, so must perform secondary initialization. It also
1503	>	* detects first submission by an external thread by looking up
1504	>	* its ThreadLocal, and creates a new shared queue if the one at
1505	>	* index if empty or contended. The plock lock body must be
1506	>	* exception-free (so no try/finally) so we optimistically
1507	>	* allocate new queues outside the lock and throw them away if
1508	>	* (very rarely) not needed.
1509	>	*
1510	>	* Secondary initialization occurs when plock is zero, to create
1511	>	* workQueue array and set plock to a valid value. This lock body
1512	>	* must also be exception-free. Because the plock seq value can
1513	>	* eventually wrap around zero, this method harmlessly fails to
1514	>	* reinitialize if workQueues exists, while still advancing plock.
1515		*/
1516		private void fullExternalPush(ForkJoinTask<?> task) {
1517		int r = 0; // random index seed
#	Line 1556 \| Line 1522 \| public class ForkJoinPool extends Abstra
1522		r += SEED_INCREMENT) && r != 0)
1523		submitters.set(z = new Submitter(r));
1524		}
1525	<	else if (r == 0) { // move to a different index
1525	>	else if (r == 0) { // move to a different index
1526		r = z.seed;
1527	<	r ^= r << 13; // same xorshift as WorkQueues
1527	>	r ^= r << 13; // same xorshift as WorkQueues
1528		r ^= r >>> 17;
1529	<	z.seed = r ^ (r << 5);
1529	>	z.seed = r ^= (r << 5);
1530		}
1531	<	else if ((ps = plock) < 0)
1531	>	if ((ps = plock) < 0)
1532		throw new RejectedExecutionException();
1533		else if (ps == 0 \|\| (ws = workQueues) == null \|\|
1534	<	(m = ws.length - 1) < 0)
1535	<	initWorkers();
1534	>	(m = ws.length - 1) < 0) { // initialize workQueues
1535	>	int p = parallelism; // find power of two table size
1536	>	int n = (p > 1) ? p - 1 : 1; // ensure at least 2 slots
1537	>	n \|= n >>> 1; n \|= n >>> 2; n \|= n >>> 4;
1538	>	n \|= n >>> 8; n \|= n >>> 16; n = (n + 1) << 1;
1539	>	WorkQueue[] nws = ((ws = workQueues) == null \|\| ws.length == 0 ?
1540	>	new WorkQueue[n] : null);
1541	>	if (((ps = plock) & PL_LOCK) != 0 \|\|
1542	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1543	>	ps = acquirePlock();
1544	>	if (((ws = workQueues) == null \|\| ws.length == 0) && nws != null)
1545	>	workQueues = nws;
1546	>	int nps = (ps & SHUTDOWN) \| ((ps + PL_LOCK) & ~SHUTDOWN);
1547	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1548	>	releasePlock(nps);
1549	>	}
1550		else if ((q = ws[k = r & m & SQMASK]) != null) {
1551		if (q.qlock == 0 && U.compareAndSwapInt(q, QLOCK, 0, 1)) {
1552		ForkJoinTask<?>[] a = q.array;
#	Line 1584 \| Line 1564 \| public class ForkJoinPool extends Abstra
1564		q.qlock = 0; // unlock
1565		}
1566		if (submitted) {
1567	<	signalWork(q);
1567	>	signalWork(ws, q);
1568		return;
1569		}
1570		}
#	Line 1592 \| Line 1572 \| public class ForkJoinPool extends Abstra
1572		}
1573		else if (((ps = plock) & PL_LOCK) == 0) { // create new queue
1574		q = new WorkQueue(this, null, SHARED_QUEUE, r);
1575	+	q.poolIndex = (short)k;
1576		if (((ps = plock) & PL_LOCK) != 0 \|\|
1577		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1578		ps = acquirePlock();
#	Line 1602 \| Line 1583 \| public class ForkJoinPool extends Abstra
1583		releasePlock(nps);
1584		}
1585		else
1586	<	r = 0; // try elsewhere while lock held
1586	>	r = 0;
1587		}
1588		}
1589
#	Line 1613 \| Line 1594 \| public class ForkJoinPool extends Abstra
1594		*/
1595		final void incrementActiveCount() {
1596		long c;
1597	<	do {} while (!U.compareAndSwapLong(this, CTL, c = ctl, c + AC_UNIT));
1597	>	do {} while (!U.compareAndSwapLong
1598	>	(this, CTL, c = ctl, ((c & ~AC_MASK) \|
1599	>	((c & AC_MASK) + AC_UNIT))));
1600		}
1601
1602		/**
1603		* Tries to create or activate a worker if too few are active.
1604		*
1605	<	* @param q the (non-null) queue holding tasks to be signalled
1605	>	* @param ws the worker array to use to find signallees
1606	>	* @param q if non-null, the queue holding tasks to be processed
1607		*/
1608	<	final void signalWork(WorkQueue q) {
1609	<	int hint = q.poolIndex;
1610	<	long c; int e, u, i, n; WorkQueue[] ws; WorkQueue w; Thread p;
1611	<	while ((u = (int)((c = ctl) >>> 32)) < 0) {
1612	<	if ((e = (int)c) > 0) {
1613	<	if ((ws = workQueues) != null && ws.length > (i = e & SMASK) &&
1630	<	(w = ws[i]) != null && w.eventCount == (e \| INT_SIGN)) {
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	<	break;
1639	<	}
1640	<	if (q.top - q.base <= 0)
1641	<	break;
1642	<	}
1643	<	else
1644	<	break;
1645	<	}
1646	<	else {
1608	>	final void signalWork(WorkQueue[] ws, WorkQueue q) {
1609	>	for (;;) {
1610	>	long c; int e, u, i; WorkQueue w; Thread p;
1611	>	if ((u = (int)((c = ctl) >>> 32)) >= 0)
1612	>	break;
1613	>	if ((e = (int)c) <= 0) {
1614		if ((short)u < 0)
1615		tryAddWorker();
1616		break;
1617		}
1618	+	if (ws == null \|\| ws.length <= (i = e & SMASK) \|\|
1619	+	(w = ws[i]) == null)
1620	+	break;
1621	+	long nc = (((long)(w.nextWait & E_MASK)) \|
1622	+	((long)(u + UAC_UNIT)) << 32);
1623	+	int ne = (e + E_SEQ) & E_MASK;
1624	+	if (w.eventCount == (e \| INT_SIGN) &&
1625	+	U.compareAndSwapLong(this, CTL, c, nc)) {
1626	+	w.eventCount = ne;
1627	+	if ((p = w.parker) != null)
1628	+	U.unpark(p);
1629	+	break;
1630	+	}
1631	+	if (q != null && q.base >= q.top)
1632	+	break;
1633		}
1634		}
1635
#	Line 1658 \| Line 1640 \| public class ForkJoinPool extends Abstra
1640		*/
1641		final void runWorker(WorkQueue w) {
1642		w.growArray(); // allocate queue
1643	<	do { w.runTask(scan(w)); } while (w.qlock >= 0);
1643	>	for (int r = w.hint; scan(w, r) == 0; ) {
1644	>	r ^= r << 13; r ^= r >>> 17; r ^= r << 5; // xorshift
1645	>	}
1646		}
1647
1648		/**
1649	<	* Scans for and, if found, returns one task, else possibly
1649	>	* Scans for and, if found, runs one task, else possibly
1650		* inactivates the worker. This method operates on single reads of
1651		* volatile state and is designed to be re-invoked continuously,
1652		* in part because it returns upon detecting inconsistencies,
1653		* contention, or state changes that indicate possible success on
1654		* re-invocation.
1655		*
1656	<	* The scan searches for tasks across queues (starting at a random
1657	<	* index, and relying on registerWorker to irregularly scatter
1658	<	* them within array to avoid bias), checking each at least twice.
1659	<	* The scan terminates upon either finding a non-empty queue, or
1660	<	* completing the sweep. If the worker is not inactivated, it
1661	<	* takes and returns a task from this queue. Otherwise, if not
1662	<	* activated, it signals workers (that may include itself) and
1663	<	* returns so caller can retry. Also returns for true if the
1664	<	* 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	<	*
1687	<	* * If not already enqueued, try to inactivate and enqueue the
1688	<	* worker on wait queue. Or, if inactivating has caused the pool
1689	<	* to be quiescent, relay to idleAwaitWork to check for
1690	<	* termination and possibly shrink pool.
1691	<	*
1692	<	* * If already enqueued and none of the above apply, possibly
1693	<	* (with 1/2 probability) park awaiting signal, else lingering to
1694	<	* help scan and signal.
1656	>	* The scan searches for tasks across queues starting at a random
1657	>	* index, checking each at least twice. The scan terminates upon
1658	>	* either finding a non-empty queue, or completing the sweep. If
1659	>	* the worker is not inactivated, it takes and runs a task from
1660	>	* this queue. Otherwise, if not activated, it tries to activate
1661	>	* itself or some other worker by signalling. On failure to find a
1662	>	* task, returns (for retry) if pool state may have changed during
1663	>	* an empty scan, or tries to inactivate if active, else possibly
1664	>	* blocks or terminates via method awaitWork.
1665		*
1666		* @param w the worker (via its WorkQueue)
1667	<	* @return a task or null if none found
1667	>	* @param r a random seed
1668	>	* @return worker qlock status if would have waited, else 0
1669		*/
1670	<	private final ForkJoinTask<?> scan(WorkQueue w) {
1670	>	private final int scan(WorkQueue w, int r) {
1671		WorkQueue[] ws; int m;
1672	<	int ps = plock; // read plock before ws
1673	<	if (w != null && (ws = workQueues) != null && (m = ws.length - 1) >= 0) {
1674	<	int ec = w.eventCount; // ec is negative if inactive
1675	<	int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
1676	<	int j = ((m + m + 1) \| MIN_SCAN) & MAX_SCAN;
1677	<	do {
1678	<	WorkQueue q; ForkJoinTask<?>[] a; int b;
1679	<	if ((q = ws[(r + j) & m]) != null && (b = q.base) - q.top < 0 &&
1680	<	(a = q.array) != null) { // probably nonempty
1681	<	int i = (((a.length - 1) & b) << ASHIFT) + ABASE;
1682	<	ForkJoinTask<?> t = (ForkJoinTask<?>)
1683	<	U.getObjectVolatile(a, i);
1684	<	if (q.base == b && ec >= 0 && t != null &&
1685	<	U.compareAndSwapObject(a, i, t, null)) {
1686	<	if ((q.base = b + 1) - q.top < 0)
1687	<	signalWork(q);
1688	<	return t; // taken
1689	<	}
1690	<	else if ((ec < 0 \|\| j < m) && (int)(ctl >> AC_SHIFT) <= 0) {
1691	<	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);
1672	>	long c = ctl; // for consistency check
1673	>	if ((ws = workQueues) != null && (m = ws.length - 1) >= 0 && w != null) {
1674	>	for (int j = m + m + 1, ec = w.eventCount;;) {
1675	>	WorkQueue q; int b, e; ForkJoinTask<?>[] a; ForkJoinTask<?> t;
1676	>	if ((q = ws[(r - j) & m]) != null &&
1677	>	(b = q.base) - q.top < 0 && (a = q.array) != null) {
1678	>	long i = (((a.length - 1) & b) << ASHIFT) + ABASE;
1679	>	if ((t = ((ForkJoinTask<?>)
1680	>	U.getObjectVolatile(a, i))) != null) {
1681	>	if (ec < 0)
1682	>	helpRelease(c, ws, w, q, b);
1683	>	else if (q.base == b &&
1684	>	U.compareAndSwapObject(a, i, t, null)) {
1685	>	U.putOrderedInt(q, QBASE, b + 1);
1686	>	if ((b + 1) - q.top < 0)
1687	>	signalWork(ws, q);
1688	>	w.runTask(t);
1689	>	}
1690	>	}
1691	>	break;
1692		}
1693	<	else if (w.eventCount < 0) { // block
1694	<	Thread wt = Thread.currentThread();
1695	<	Thread.interrupted(); // clear status
1696	<	U.putObject(wt, PARKBLOCKER, this);
1697	<	w.parker = wt; // emulate LockSupport.park
1698	<	if (w.eventCount < 0) // recheck
1699	<	U.park(false, 0L);
1700	<	w.parker = null;
1701	<	U.putObject(wt, PARKBLOCKER, null);
1693	>	else if (--j < 0) {
1694	>	if ((ec \| (e = (int)c)) < 0) // inactive or terminating
1695	>	return awaitWork(w, c, ec);
1696	>	else if (ctl == c) { // try to inactivate and enqueue
1697	>	long nc = (long)ec \| ((c - AC_UNIT) & (AC_MASK\|TC_MASK));
1698	>	w.nextWait = e;
1699	>	w.eventCount = ec \| INT_SIGN;
1700	>	if (!U.compareAndSwapLong(this, CTL, c, nc))
1701	>	w.eventCount = ec; // back out
1702	>	}
1703	>	break;
1704		}
1705		}
1757	–	if (h >= 0 \|\| w.hint >= 0) // signal others before retry
1758	–	helpSignalHint(w);
1706		}
1707	<	return null;
1707	>	return 0;
1708		}
1709
1710		/**
1711	<	* If inactivating worker w has caused the pool to become
1712	<	* quiescent, checks for pool termination, and, so long as this is
1713	<	* not the only worker, waits for event for up to a given
1714	<	* duration. On timeout, if ctl has not changed, terminates the
1715	<	* worker, which will in turn wake up another worker to possibly
1716	<	* repeat this process.
1711	>	* A continuation of scan(), possibly blocking or terminating
1712	>	* worker w. Returns without blocking if pool state has apparently
1713	>	* changed since last invocation. Also, if inactivating w has
1714	>	* caused the pool to become quiescent, checks for pool
1715	>	* termination, and, so long as this is not the only worker, waits
1716	>	* for event for up to a given duration. On timeout, if ctl has
1717	>	* not changed, terminates the worker, which will in turn wake up
1718	>	* another worker to possibly repeat this process.
1719		*
1720		* @param w the calling worker
1721	<	* @param currentCtl the ctl value triggering possible quiescence
1722	<	* @param prevCtl the ctl value to restore if thread is terminated
1721	>	* @param c the ctl value on entry to scan
1722	>	* @param ec the worker's eventCount on entry to scan
1723		*/
1724	<	private void idleAwaitWork(WorkQueue w, long currentCtl, long prevCtl) {
1725	<	if (w != null && w.eventCount < 0 &&
1726	<	!tryTerminate(false, false) && (int)prevCtl != 0) {
1727	<	int dc = -(short)(currentCtl >>> TC_SHIFT);
1728	<	long parkTime = dc < 0 ? FAST_IDLE_TIMEOUT: (dc + 1) * IDLE_TIMEOUT;
1729	<	long deadline = System.nanoTime() + parkTime - TIMEOUT_SLOP;
1730	<	Thread wt = Thread.currentThread();
1731	<	while (ctl == currentCtl) {
1732	<	Thread.interrupted(); // timed variant of version in scan()
1733	<	U.putObject(wt, PARKBLOCKER, this);
1734	<	w.parker = wt;
1735	<	if (ctl == currentCtl)
1736	<	U.park(false, parkTime);
1737	<	w.parker = null;
1738	<	U.putObject(wt, PARKBLOCKER, null);
1790	<	if (ctl != currentCtl)
1791	<	break;
1792	<	if (deadline - System.nanoTime() <= 0L &&
1793	<	U.compareAndSwapLong(this, CTL, currentCtl, prevCtl)) {
1794	<	w.eventCount = (w.eventCount + E_SEQ) \| E_MASK;
1795	<	w.qlock = -1; // shrink
1796	<	break;
1797	<	}
1724	>	private final int awaitWork(WorkQueue w, long c, int ec) {
1725	>	int stat, ns; long parkTime, deadline;
1726	>	if ((stat = w.qlock) >= 0 && w.eventCount == ec && ctl == c &&
1727	>	!Thread.interrupted()) {
1728	>	int e = (int)c;
1729	>	int u = (int)(c >>> 32);
1730	>	int d = (u >> UAC_SHIFT) + parallelism; // active count
1731	>
1732	>	if (e < 0 \|\| (d <= 0 && tryTerminate(false, false)))
1733	>	stat = w.qlock = -1; // pool is terminating
1734	>	else if ((ns = w.nsteals) != 0) { // collect steals and retry
1735	>	long sc;
1736	>	w.nsteals = 0;
1737	>	do {} while (!U.compareAndSwapLong(this, STEALCOUNT,
1738	>	sc = stealCount, sc + ns));
1739		}
1740	<	}
1741	<	}
1742	<
1743	<	/**
1744	<	* Scans through queues looking for work while joining a task; if
1745	<	* any present, signals. May return early if more signalling is
1746	<	* detectably unneeded.
1747	<	*
1748	<	* @param task return early if done
1749	<	* @param origin an index to start scan
1750	<	*/
1751	<	private void helpSignal(ForkJoinTask<?> task, int origin) {
1752	<	WorkQueue[] ws; WorkQueue w; Thread p; long c; int m, u, e, i, s;
1753	<	if (task != null && task.status >= 0 &&
1754	<	(u = (int)(ctl >>> 32)) < 0 && (u >> UAC_SHIFT) < 0 &&
1755	<	(ws = workQueues) != null && (m = ws.length - 1) >= 0) {
1756	<	outer: for (int k = origin, j = m; j >= 0; --j) {
1757	<	WorkQueue q = ws[k++ & m];
1758	<	for (int n = m;;) { // limit to at most m signals
1759	<	if (task.status < 0)
1760	<	break outer;
1761	<	if (q == null \|\|
1762	<	((s = -q.base + q.top) <= n && (n = s) <= 0))
1763	<	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	<	}
1740	>	else {
1741	>	long pc = ((d > 0 \|\| ec != (e \| INT_SIGN)) ? 0L :
1742	>	((long)(w.nextWait & E_MASK)) \| // ctl to restore
1743	>	((long)(u + UAC_UNIT)) << 32);
1744	>	if (pc != 0L) { // timed wait if last waiter
1745	>	int dc = -(short)(c >>> TC_SHIFT);
1746	>	parkTime = (dc < 0 ? FAST_IDLE_TIMEOUT:
1747	>	(dc + 1) * IDLE_TIMEOUT);
1748	>	deadline = System.nanoTime() + parkTime - TIMEOUT_SLOP;
1749	>	}
1750	>	else
1751	>	parkTime = deadline = 0L;
1752	>	if (w.eventCount == ec && ctl == c) {
1753	>	Thread wt = Thread.currentThread();
1754	>	U.putObject(wt, PARKBLOCKER, this);
1755	>	w.parker = wt; // emulate LockSupport.park
1756	>	if (w.eventCount == ec && ctl == c)
1757	>	U.park(false, parkTime); // must recheck before park
1758	>	w.parker = null;
1759	>	U.putObject(wt, PARKBLOCKER, null);
1760	>	if (parkTime != 0L && ctl == c &&
1761	>	deadline - System.nanoTime() <= 0L &&
1762	>	U.compareAndSwapLong(this, CTL, c, pc))
1763	>	stat = w.qlock = -1; // shrink pool
1764		}
1765		}
1766		}
1767	+	return stat;
1768		}
1769
1770		/**
1771	<	* Signals other workers if tasks are present in hinted queue.
1772	<	*
1773	<	* @param caller the worker with the hint
1774	<	*/
1775	<	private void helpSignalHint(WorkQueue caller) {
1776	<	WorkQueue[] ws; WorkQueue q, w; Thread p; long c; int h, m, u, e, i, s;
1777	<	if (caller != null && (h = caller.hint) >= 0) {
1778	<	caller.hint = -1;
1779	<	if ((u = (int)(ctl >>> 32)) < 0 && (u >> UAC_SHIFT) < 0 &&
1780	<	(ws = workQueues) != null && (m = ws.length - 1) >= 0 &&
1781	<	(q = ws[h & m]) != null) {
1782	<	for (int n = 2;;) { // limit to at most 2 signals
1783	<	int idleCount = (caller.eventCount < 0) ? 0 : -1;
1784	<	if (((s = idleCount - q.base + q.top) <= n &&
1785	<	(n = s) <= 0) \|\|
1786	<	(u = (int)((c = ctl) >>> 32)) >= 0 \|\|
1787	<	(e = (int)c) <= 0 \|\| m < (i = e & SMASK) \|\|
1788	<	(w = ws[i]) == null)
1789	<	break;
1790	<	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	<	}
1771	>	* Possibly releases (signals) a worker. Called only from scan()
1772	>	* when a worker with apparently inactive status finds a non-empty
1773	>	* queue. This requires revalidating all of the associated state
1774	>	* from caller.
1775	>	*/
1776	>	private final void helpRelease(long c, WorkQueue[] ws, WorkQueue w,
1777	>	WorkQueue q, int b) {
1778	>	WorkQueue v; int e, i; Thread p;
1779	>	if (w != null && w.eventCount < 0 && (e = (int)c) > 0 &&
1780	>	ws != null && ws.length > (i = e & SMASK) &&
1781	>	(v = ws[i]) != null && ctl == c) {
1782	>	long nc = (((long)(v.nextWait & E_MASK)) \|
1783	>	((long)((int)(c >>> 32) + UAC_UNIT)) << 32);
1784	>	int ne = (e + E_SEQ) & E_MASK;
1785	>	if (q != null && q.base == b && w.eventCount < 0 &&
1786	>	v.eventCount == (e \| INT_SIGN) &&
1787	>	U.compareAndSwapLong(this, CTL, c, nc)) {
1788	>	v.eventCount = ne;
1789	>	if ((p = v.parker) != null)
1790	>	U.unpark(p);
1791		}
1792		}
1793		}
#	Line 1895 \| Line 1812 \| public class ForkJoinPool extends Abstra
1812		*/
1813		private int tryHelpStealer(WorkQueue joiner, ForkJoinTask<?> task) {
1814		int stat = 0, steps = 0; // bound to avoid cycles
1815	<	if (joiner != null && task != null) { // hoist null checks
1815	>	if (task != null && joiner != null &&
1816	>	joiner.base - joiner.top >= 0) { // hoist checks
1817		restart: for (;;) {
1818		ForkJoinTask<?> subtask = task; // current target
1819		for (WorkQueue j = joiner, v;;) { // v is stealer of subtask
#	Line 1922 \| Line 1840 \| public class ForkJoinPool extends Abstra
1840		}
1841		}
1842		for (;;) { // help stealer or descend to its stealer
1843	<	ForkJoinTask[] a; int b;
1843	>	ForkJoinTask[] a; int b;
1844		if (subtask.status < 0) // surround probes with
1845		continue restart; // consistency checks
1846		if ((b = v.base) - v.top < 0 && (a = v.array) != null) {
#	Line 1933 \| Line 1851 \| public class ForkJoinPool extends Abstra
1851		v.currentSteal != subtask)
1852		continue restart; // stale
1853		stat = 1; // apparent progress
1854	<	if (t != null && v.base == b &&
1855	<	U.compareAndSwapObject(a, i, t, null)) {
1856	<	v.base = b + 1; // help stealer
1857	<	joiner.runSubtask(t);
1854	>	if (v.base == b) {
1855	>	if (t == null)
1856	>	break restart;
1857	>	if (U.compareAndSwapObject(a, i, t, null)) {
1858	>	U.putOrderedInt(v, QBASE, b + 1);
1859	>	ForkJoinTask<?> ps = joiner.currentSteal;
1860	>	int jt = joiner.top;
1861	>	do {
1862	>	joiner.currentSteal = t;
1863	>	t.doExec(); // clear local tasks too
1864	>	} while (task.status >= 0 &&
1865	>	joiner.top != jt &&
1866	>	(t = joiner.pop()) != null);
1867	>	joiner.currentSteal = ps;
1868	>	break restart;
1869	>	}
1870		}
1941	–	else if (v.base == b && ++steps == MAX_HELP)
1942	–	break restart; // v apparently stalled
1871		}
1872		else { // empty -- try to descend
1873		ForkJoinTask<?> next = v.currentJoin;
#	Line 1966 \| Line 1894 \| public class ForkJoinPool extends Abstra
1894		* and run tasks within the target's computation.
1895		*
1896		* @param task the task to join
1969	–	* @param mode if shared, exit upon completing any task
1970	–	* if all workers are active
1971	–	*
1897		*/
1898	<	private int helpComplete(ForkJoinTask<?> task, int mode) {
1899	<	WorkQueue[] ws; WorkQueue q; int m, n, s, u;
1900	<	if (task != null && (ws = workQueues) != null &&
1901	<	(m = ws.length - 1) >= 0) {
1902	<	for (int j = 1, origin = j;;) {
1898	>	private int helpComplete(WorkQueue joiner, CountedCompleter<?> task) {
1899	>	WorkQueue[] ws; int m;
1900	>	int s = 0;
1901	>	if ((ws = workQueues) != null && (m = ws.length - 1) >= 0 &&
1902	>	joiner != null && task != null) {
1903	>	int j = joiner.poolIndex;
1904	>	int scans = m + m + 1;
1905	>	long c = 0L; // for stability check
1906	>	for (int k = scans; ; j += 2) {
1907	>	WorkQueue q;
1908		if ((s = task.status) < 0)
1909	<	return s;
1910	<	if ((q = ws[j & m]) != null && q.pollAndExecCC(task)) {
1911	<	origin = j;
1912	<	if (mode == SHARED_QUEUE &&
1913	<	((u = (int)(ctl >>> 32)) >= 0 \|\| (u >> UAC_SHIFT) >= 0))
1909	>	break;
1910	>	else if (joiner.internalPopAndExecCC(task))
1911	>	k = scans;
1912	>	else if ((s = task.status) < 0)
1913	>	break;
1914	>	else if ((q = ws[j & m]) != null && q.pollAndExecCC(task))
1915	>	k = scans;
1916	>	else if (--k < 0) {
1917	>	if (c == (c = ctl))
1918		break;
1919	+	k = scans;
1920		}
1986	–	else if ((j = (j + 2) & m) == origin)
1987	–	break;
1921		}
1922		}
1923	<	return 0;
1923	>	return s;
1924		}
1925
1926		/**
#	Line 1996 \| Line 1929 \| public class ForkJoinPool extends Abstra
1929		* for blocking. Fails on contention or termination. Otherwise,
1930		* adds a new thread if no idle workers are available and pool
1931		* may become starved.
1932	+	*
1933	+	* @param c the assumed ctl value
1934		*/
1935	<	final boolean tryCompensate() {
1936	<	int pc = config & SMASK, e, i, tc; long c;
1937	<	WorkQueue[] ws; WorkQueue w; Thread p;
1938	<	if ((ws = workQueues) != null && (e = (int)(c = ctl)) >= 0) {
1939	<	if (e != 0 && (i = e & SMASK) < ws.length &&
1940	<	(w = ws[i]) != null && w.eventCount == (e \| INT_SIGN)) {
1935	>	final boolean tryCompensate(long c) {
1936	>	WorkQueue[] ws = workQueues;
1937	>	int pc = parallelism, e = (int)c, m, tc;
1938	>	if (ws != null && (m = ws.length - 1) >= 0 && e >= 0 && ctl == c) {
1939	>	WorkQueue w = ws[e & m];
1940	>	if (e != 0 && w != null) {
1941	>	Thread p;
1942		long nc = ((long)(w.nextWait & E_MASK) \|
1943		(c & (AC_MASK\|TC_MASK)));
1944	<	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1945	<	w.eventCount = (e + E_SEQ) & E_MASK;
1944	>	int ne = (e + E_SEQ) & E_MASK;
1945	>	if (w.eventCount == (e \| INT_SIGN) &&
1946	>	U.compareAndSwapLong(this, CTL, c, nc)) {
1947	>	w.eventCount = ne;
1948		if ((p = w.parker) != null)
1949		U.unpark(p);
1950		return true; // replace with idle worker
#	Line 2049 \| Line 1987 \| public class ForkJoinPool extends Abstra
1987		*/
1988		final int awaitJoin(WorkQueue joiner, ForkJoinTask<?> task) {
1989		int s = 0;
1990	<	if (joiner != null && task != null && (s = task.status) >= 0) {
1990	>	if (task != null && (s = task.status) >= 0 && joiner != null) {
1991		ForkJoinTask<?> prevJoin = joiner.currentJoin;
1992		joiner.currentJoin = task;
1993	<	do {} while ((s = task.status) >= 0 && !joiner.isEmpty() &&
1994	<	joiner.tryRemoveAndExec(task)); // process local tasks
1995	<	if (s >= 0 && (s = task.status) >= 0) {
1996	<	helpSignal(task, joiner.poolIndex);
1997	<	if ((s = task.status) >= 0 &&
2060	<	(task instanceof CountedCompleter))
2061	<	s = helpComplete(task, LIFO_QUEUE);
2062	<	}
1993	>	do {} while (joiner.tryRemoveAndExec(task) && // process local tasks
1994	>	(s = task.status) >= 0);
1995	>	if (s >= 0 && (task instanceof CountedCompleter))
1996	>	s = helpComplete(joiner, (CountedCompleter<?>)task);
1997	>	long cc = 0; // for stability checks
1998		while (s >= 0 && (s = task.status) >= 0) {
1999	<	if ((!joiner.isEmpty() \|\| // try helping
2065	<	(s = tryHelpStealer(joiner, task)) == 0) &&
1999	>	if ((s = tryHelpStealer(joiner, task)) == 0 &&
2000		(s = task.status) >= 0) {
2001	<	helpSignal(task, joiner.poolIndex);
2002	<	if ((s = task.status) >= 0 && tryCompensate()) {
2001	>	if (!tryCompensate(cc))
2002	>	cc = ctl;
2003	>	else {
2004		if (task.trySetSignal() && (s = task.status) >= 0) {
2005		synchronized (task) {
2006		if (task.status >= 0) {
#	Line 2078 \| Line 2013 \| public class ForkJoinPool extends Abstra
2013		task.notifyAll();
2014		}
2015		}
2016	<	long c; // re-activate
2016	>	long c; // reactivate
2017		do {} while (!U.compareAndSwapLong
2018	<	(this, CTL, c = ctl, c + AC_UNIT));
2018	>	(this, CTL, c = ctl,
2019	>	((c & ~AC_MASK) \|
2020	>	((c & AC_MASK) + AC_UNIT))));
2021		}
2022		}
2023		}
#	Line 2102 \| Line 2039 \| public class ForkJoinPool extends Abstra
2039		if (joiner != null && task != null && (s = task.status) >= 0) {
2040		ForkJoinTask<?> prevJoin = joiner.currentJoin;
2041		joiner.currentJoin = task;
2042	<	do {} while ((s = task.status) >= 0 && !joiner.isEmpty() &&
2043	<	joiner.tryRemoveAndExec(task));
2044	<	if (s >= 0 && (s = task.status) >= 0) {
2045	<	helpSignal(task, joiner.poolIndex);
2046	<	if ((s = task.status) >= 0 &&
2110	<	(task instanceof CountedCompleter))
2111	<	s = helpComplete(task, LIFO_QUEUE);
2112	<	}
2113	<	if (s >= 0 && joiner.isEmpty()) {
2042	>	do {} while (joiner.tryRemoveAndExec(task) && // process local tasks
2043	>	(s = task.status) >= 0);
2044	>	if (s >= 0) {
2045	>	if (task instanceof CountedCompleter)
2046	>	helpComplete(joiner, (CountedCompleter<?>)task);
2047		do {} while (task.status >= 0 &&
2048		tryHelpStealer(joiner, task) > 0);
2049		}
#	Line 2120 \| Line 2053 \| public class ForkJoinPool extends Abstra
2053
2054		/**
2055		* Returns a (probably) non-empty steal queue, if one is found
2056	<	* during a random, then cyclic scan, else null. This method must
2057	<	* be retried by caller if, by the time it tries to use the queue,
2058	<	* it is empty.
2059	<	* @param r a (random) seed for scanning
2060	<	*/
2061	<	private WorkQueue findNonEmptyStealQueue(int r) {
2062	<	for (WorkQueue[] ws;;) {
2063	<	int ps = plock, m, n;
2064	<	if ((ws = workQueues) == null \|\| (m = ws.length - 1) < 1)
2065	<	return null;
2066	<	for (int j = (m + 1) << 2; ;) {
2067	<	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;
2143	<	break;
2056	>	* during a scan, else null. This method must be retried by
2057	>	* caller if, by the time it tries to use the queue, it is empty.
2058	>	*/
2059	>	private WorkQueue findNonEmptyStealQueue() {
2060	>	int r = ThreadLocalRandom.current().nextInt();
2061	>	for (;;) {
2062	>	int ps = plock, m; WorkQueue[] ws; WorkQueue q;
2063	>	if ((ws = workQueues) != null && (m = ws.length - 1) >= 0) {
2064	>	for (int j = (m + 1) << 2; j >= 0; --j) {
2065	>	if ((q = ws[(((r - j) << 1) \| 1) & m]) != null &&
2066	>	q.base - q.top < 0)
2067	>	return q;
2068		}
2069		}
2070	+	if (plock == ps)
2071	+	return null;
2072		}
2073		}
2074
#	Line 2153 \| Line 2079 \| public class ForkJoinPool extends Abstra
2079		* find tasks either.
2080		*/
2081		final void helpQuiescePool(WorkQueue w) {
2082	+	ForkJoinTask<?> ps = w.currentSteal;
2083		for (boolean active = true;;) {
2084	<	ForkJoinTask<?> localTask; // exhaust local queue
2085	<	while ((localTask = w.nextLocalTask()) != null)
2086	<	localTask.doExec();
2087	<	// Similar to loop in scan(), but ignoring submissions
2161	<	WorkQueue q = findNonEmptyStealQueue(w.nextSeed());
2162	<	if (q != null) {
2163	<	ForkJoinTask<?> t; int b;
2084	>	long c; WorkQueue q; ForkJoinTask<?> t; int b;
2085	>	while ((t = w.nextLocalTask()) != null)
2086	>	t.doExec();
2087	>	if ((q = findNonEmptyStealQueue()) != null) {
2088		if (!active) { // re-establish active count
2165	–	long c;
2089		active = true;
2090		do {} while (!U.compareAndSwapLong
2091	<	(this, CTL, c = ctl, c + AC_UNIT));
2091	>	(this, CTL, c = ctl,
2092	>	((c & ~AC_MASK) \|
2093	>	((c & AC_MASK) + AC_UNIT))));
2094	>	}
2095	>	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null) {
2096	>	(w.currentSteal = t).doExec();
2097	>	w.currentSteal = ps;
2098		}
2170	–	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null)
2171	–	w.runSubtask(t);
2099		}
2100	<	else {
2101	<	long c;
2102	<	if (active) { // decrement active count without queuing
2100	>	else if (active) { // decrement active count without queuing
2101	>	long nc = ((c = ctl) & ~AC_MASK) \| ((c & AC_MASK) - AC_UNIT);
2102	>	if ((int)(nc >> AC_SHIFT) + parallelism == 0)
2103	>	break; // bypass decrement-then-increment
2104	>	if (U.compareAndSwapLong(this, CTL, c, nc))
2105		active = false;
2177	–	do {} while (!U.compareAndSwapLong
2178	–	(this, CTL, c = ctl, c -= AC_UNIT));
2179	–	}
2180	–	else
2181	–	c = ctl; // re-increment on exit
2182	–	if ((int)(c >> AC_SHIFT) + (config & SMASK) == 0) {
2183	–	do {} while (!U.compareAndSwapLong
2184	–	(this, CTL, c = ctl, c + AC_UNIT));
2185	–	break;
2186	–	}
2106		}
2107	+	else if ((int)((c = ctl) >> AC_SHIFT) + parallelism <= 0 &&
2108	+	U.compareAndSwapLong
2109	+	(this, CTL, c, ((c & ~AC_MASK) \|
2110	+	((c & AC_MASK) + AC_UNIT))))
2111	+	break;
2112		}
2113		}
2114
#	Line 2198 \| Line 2122 \| public class ForkJoinPool extends Abstra
2122		WorkQueue q; int b;
2123		if ((t = w.nextLocalTask()) != null)
2124		return t;
2125	<	if ((q = findNonEmptyStealQueue(w.nextSeed())) == null)
2125	>	if ((q = findNonEmptyStealQueue()) == null)
2126		return null;
2127		if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null)
2128		return t;
#	Line 2230 \| Line 2154 \| public class ForkJoinPool extends Abstra
2154		* producing extra tasks amortizes the uncertainty of progress and
2155		* diffusion assumptions.
2156		*
2157	<	* So, users will want to use values larger, but not much larger
2157	>	* So, users will want to use values larger (but not much larger)
2158		* than 1 to both smooth over transient shortages and hedge
2159		* against uneven progress; as traded off against the cost of
2160		* extra task overhead. We leave the user to pick a threshold
#	Line 2254 \| Line 2178 \| public class ForkJoinPool extends Abstra
2178		static int getSurplusQueuedTaskCount() {
2179		Thread t; ForkJoinWorkerThread wt; ForkJoinPool pool; WorkQueue q;
2180		if (((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)) {
2181	<	int p = (pool = (wt = (ForkJoinWorkerThread)t).pool).config & SMASK;
2181	>	int p = (pool = (wt = (ForkJoinWorkerThread)t).pool).parallelism;
2182		int n = (q = wt.workQueue).top - q.base;
2183		int a = (int)(pool.ctl >> AC_SHIFT) + p;
2184		return n - (a > (p >>>= 1) ? 0 :
#	Line 2283 \| Line 2207 \| public class ForkJoinPool extends Abstra
2207		* @return true if now terminating or terminated
2208		*/
2209		private boolean tryTerminate(boolean now, boolean enable) {
2210	<	if (this == commonPool) // cannot shut down
2210	>	int ps;
2211	>	if (this == common) // cannot shut down
2212		return false;
2213	+	if ((ps = plock) >= 0) { // enable by setting plock
2214	+	if (!enable)
2215	+	return false;
2216	+	if ((ps & PL_LOCK) != 0 \|\|
2217	+	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
2218	+	ps = acquirePlock();
2219	+	int nps = ((ps + PL_LOCK) & ~SHUTDOWN) \| SHUTDOWN;
2220	+	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
2221	+	releasePlock(nps);
2222	+	}
2223		for (long c;;) {
2224	<	if (((c = ctl) & STOP_BIT) != 0) { // already terminating
2225	<	if ((short)(c >>> TC_SHIFT) == -(config & SMASK)) {
2224	>	if (((c = ctl) & STOP_BIT) != 0) { // already terminating
2225	>	if ((short)(c >>> TC_SHIFT) + parallelism <= 0) {
2226		synchronized (this) {
2227	<	notifyAll(); // signal when 0 workers
2227	>	notifyAll(); // signal when 0 workers
2228		}
2229		}
2230		return true;
2231		}
2232	<	if (plock >= 0) { // not yet enabled
2233	<	int ps;
2234	<	if (!enable)
2300	<	return false;
2301	<	if (((ps = plock) & PL_LOCK) != 0 \|\|
2302	<	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
2303	<	ps = acquirePlock();
2304	<	int nps = SHUTDOWN;
2305	<	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
2306	<	releasePlock(nps);
2307	<	}
2308	<	if (!now) { // check if idle & no tasks
2309	<	if ((int)(c >> AC_SHIFT) != -(config & SMASK) \|\|
2310	<	hasQueuedSubmissions())
2232	>	if (!now) { // check if idle & no tasks
2233	>	WorkQueue[] ws; WorkQueue w;
2234	>	if ((int)(c >> AC_SHIFT) + parallelism > 0)
2235		return false;
2236	<	// Check for unqueued inactive workers. One pass suffices.
2237	<	WorkQueue[] ws = workQueues; WorkQueue w;
2238	<	if (ws != null) {
2239	<	for (int i = 1; i < ws.length; i += 2) {
2240	<	if ((w = ws[i]) != null && w.eventCount >= 0)
2236	>	if ((ws = workQueues) != null) {
2237	>	for (int i = 0; i < ws.length; ++i) {
2238	>	if ((w = ws[i]) != null &&
2239	>	(!w.isEmpty() \|\|
2240	>	((i & 1) != 0 && w.eventCount >= 0))) {
2241	>	signalWork(ws, w);
2242		return false;
2243	+	}
2244		}
2245		}
2246		}
2247		if (U.compareAndSwapLong(this, CTL, c, c \| STOP_BIT)) {
2248		for (int pass = 0; pass < 3; ++pass) {
2249	<	WorkQueue[] ws = workQueues;
2250	<	if (ws != null) {
2325	<	WorkQueue w;
2249	>	WorkQueue[] ws; WorkQueue w; Thread wt;
2250	>	if ((ws = workQueues) != null) {
2251		int n = ws.length;
2252		for (int i = 0; i < n; ++i) {
2253		if ((w = ws[i]) != null) {
2254		w.qlock = -1;
2255		if (pass > 0) {
2256		w.cancelAll();
2257	<	if (pass > 1)
2258	<	w.interruptOwner();
2257	>	if (pass > 1 && (wt = w.owner) != null) {
2258	>	if (!wt.isInterrupted()) {
2259	>	try {
2260	>	wt.interrupt();
2261	>	} catch (Throwable ignore) {
2262	>	}
2263	>	}
2264	>	U.unpark(wt);
2265	>	}
2266		}
2267		}
2268		}
2269		// Wake up workers parked on event queue
2270		int i, e; long cc; Thread p;
2271		while ((e = (int)(cc = ctl) & E_MASK) != 0 &&
2272	<	(i = e & SMASK) < n &&
2272	>	(i = e & SMASK) < n && i >= 0 &&
2273		(w = ws[i]) != null) {
2274		long nc = ((long)(w.nextWait & E_MASK) \|
2275		((cc + AC_UNIT) & AC_MASK) \|
#	Line 2363 \| Line 2295 \| public class ForkJoinPool extends Abstra
2295		* least one task.
2296		*/
2297		static WorkQueue commonSubmitterQueue() {
2298	<	ForkJoinPool p; WorkQueue[] ws; int m; Submitter z;
2298	>	Submitter z; ForkJoinPool p; WorkQueue[] ws; int m, r;
2299		return ((z = submitters.get()) != null &&
2300	<	(p = commonPool) != null &&
2300	>	(p = common) != null &&
2301		(ws = p.workQueues) != null &&
2302		(m = ws.length - 1) >= 0) ?
2303		ws[m & z.seed & SQMASK] : null;
#	Line 2374 \| Line 2306 \| public class ForkJoinPool extends Abstra
2306		/**
2307		* Tries to pop the given task from submitter's queue in common pool.
2308		*/
2309	<	static boolean tryExternalUnpush(ForkJoinTask<?> t) {
2310	<	ForkJoinPool p; WorkQueue[] ws; WorkQueue q; Submitter z;
2311	<	ForkJoinTask<?>[] a; int m, s;
2312	<	if (t != null &&
2313	<	(z = submitters.get()) != null &&
2314	<	(p = commonPool) != null &&
2315	<	(ws = p.workQueues) != null &&
2316	<	(m = ws.length - 1) >= 0 &&
2317	<	(q = ws[m & z.seed & SQMASK]) != null &&
2386	<	(s = q.top) != q.base &&
2387	<	(a = q.array) != null) {
2309	>	final boolean tryExternalUnpush(ForkJoinTask<?> task) {
2310	>	WorkQueue joiner; ForkJoinTask<?>[] a; int m, s;
2311	>	Submitter z = submitters.get();
2312	>	WorkQueue[] ws = workQueues;
2313	>	boolean popped = false;
2314	>	if (z != null && ws != null && (m = ws.length - 1) >= 0 &&
2315	>	(joiner = ws[z.seed & m & SQMASK]) != null &&
2316	>	joiner.base != (s = joiner.top) &&
2317	>	(a = joiner.array) != null) {
2318		long j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE;
2319	<	if (U.getObject(a, j) == t &&
2320	<	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2321	<	if (q.array == a && q.top == s && // recheck
2322	<	U.compareAndSwapObject(a, j, t, null)) {
2323	<	q.top = s - 1;
2324	<	q.qlock = 0;
2395	<	return true;
2319	>	if (U.getObject(a, j) == task &&
2320	>	U.compareAndSwapInt(joiner, QLOCK, 0, 1)) {
2321	>	if (joiner.top == s && joiner.array == a &&
2322	>	U.compareAndSwapObject(a, j, task, null)) {
2323	>	joiner.top = s - 1;
2324	>	popped = true;
2325		}
2326	<	q.qlock = 0;
2326	>	joiner.qlock = 0;
2327		}
2328		}
2329	<	return false;
2329	>	return popped;
2330		}
2331
2332	<	/**
2333	<	* Tries to pop and run local tasks within the same computation
2334	<	* as the given root. On failure, tries to help complete from
2335	<	* other queues via helpComplete.
2336	<	*/
2337	<	private void externalHelpComplete(WorkQueue q, ForkJoinTask<?> root) {
2338	<	ForkJoinTask<?>[] a; int m;
2339	<	if (q != null && (a = q.array) != null && (m = (a.length - 1)) >= 0 &&
2340	<	root != null && root.status >= 0) {
2341	<	for (;;) {
2342	<	int s, u; Object o; CountedCompleter<?> task = null;
2343	<	if ((s = q.top) - q.base > 0) {
2344	<	long j = ((m & (s - 1)) << ASHIFT) + ABASE;
2416	<	if ((o = U.getObject(a, j)) != null &&
2417	<	(o instanceof CountedCompleter)) {
2418	<	CountedCompleter<?> t = (CountedCompleter<?>)o, r = t;
2419	<	do {
2420	<	if (r == root) {
2421	<	if (U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2422	<	if (q.array == a && q.top == s &&
2423	<	U.compareAndSwapObject(a, j, t, null)) {
2424	<	q.top = s - 1;
2425	<	task = t;
2426	<	}
2427	<	q.qlock = 0;
2428	<	}
2429	<	break;
2430	<	}
2431	<	} while ((r = r.completer) != null);
2432	<	}
2433	<	}
2434	<	if (task != null)
2435	<	task.doExec();
2436	<	if (root.status < 0 \|\|
2437	<	(u = (int)(ctl >>> 32)) >= 0 \|\| (u >> UAC_SHIFT) >= 0)
2332	>	final int externalHelpComplete(CountedCompleter<?> task) {
2333	>	WorkQueue joiner; int m, j;
2334	>	Submitter z = submitters.get();
2335	>	WorkQueue[] ws = workQueues;
2336	>	int s = 0;
2337	>	if (z != null && ws != null && (m = ws.length - 1) >= 0 &&
2338	>	(joiner = ws[(j = z.seed) & m & SQMASK]) != null && task != null) {
2339	>	int scans = m + m + 1;
2340	>	long c = 0L; // for stability check
2341	>	j \|= 1; // poll odd queues
2342	>	for (int k = scans; ; j += 2) {
2343	>	WorkQueue q;
2344	>	if ((s = task.status) < 0)
2345		break;
2346	<	if (task == null) {
2347	<	helpSignal(root, q.poolIndex);
2348	<	if (root.status >= 0)
2442	<	helpComplete(root, SHARED_QUEUE);
2346	>	else if (joiner.externalPopAndExecCC(task))
2347	>	k = scans;
2348	>	else if ((s = task.status) < 0)
2349		break;
2350	+	else if ((q = ws[j & m]) != null && q.pollAndExecCC(task))
2351	+	k = scans;
2352	+	else if (--k < 0) {
2353	+	if (c == (c = ctl))
2354	+	break;
2355	+	k = scans;
2356		}
2357		}
2358		}
2359	<	}
2448	<
2449	<	/**
2450	<	* Tries to help execute or signal availability of the given task
2451	<	* from submitter's queue in common pool.
2452	<	*/
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;
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	<	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	<	}
2478	<	}
2479	<	if (t.status >= 0) {
2480	<	if (t instanceof CountedCompleter)
2481	<	p.externalHelpComplete(q, t);
2482	<	else
2483	<	p.helpSignal(t, q.poolIndex);
2484	<	}
2485	<	}
2486	<	}
2487	<
2488	<	/**
2489	<	* Restricted version of helpQuiescePool for external callers
2490	<	*/
2491	<	static void externalHelpQuiescePool() {
2492	<	ForkJoinPool p; ForkJoinTask<?> t; WorkQueue q; int b;
2493	<	if ((p = commonPool) != null &&
2494	<	(q = p.findNonEmptyStealQueue(1)) != null &&
2495	<	(b = q.base) - q.top < 0 &&
2496	<	(t = q.pollAt(b)) != null)
2497	<	t.doExec();
2359	>	return s;
2360		}
2361
2362		// Exported methods
#	Line 2513 \| Line 2375 \| public class ForkJoinPool extends Abstra
2375		* java.lang.RuntimePermission}{@code ("modifyThread")}
2376		*/
2377		public ForkJoinPool() {
2378	<	this(Runtime.getRuntime().availableProcessors(),
2378	>	this(Math.min(MAX_CAP, Runtime.getRuntime().availableProcessors()),
2379		defaultForkJoinWorkerThreadFactory, null, false);
2380		}
2381
#	Line 2561 \| Line 2423 \| public class ForkJoinPool extends Abstra
2423		*/
2424		public ForkJoinPool(int parallelism,
2425		ForkJoinWorkerThreadFactory factory,
2426	<	Thread.UncaughtExceptionHandler handler,
2426	>	UncaughtExceptionHandler handler,
2427		boolean asyncMode) {
2428	+	this(checkParallelism(parallelism),
2429	+	checkFactory(factory),
2430	+	handler,
2431	+	(asyncMode ? FIFO_QUEUE : LIFO_QUEUE),
2432	+	"ForkJoinPool-" + nextPoolId() + "-worker-");
2433		checkPermission();
2434	<	if (factory == null)
2435	<	throw new NullPointerException();
2434	>	}
2435	>
2436	>	private static int checkParallelism(int parallelism) {
2437		if (parallelism <= 0 \|\| parallelism > MAX_CAP)
2438		throw new IllegalArgumentException();
2439	<	this.factory = factory;
2440	<	this.ueh = handler;
2441	<	this.config = parallelism \| (asyncMode ? (FIFO_QUEUE << 16) : 0);
2442	<	long np = (long)(-parallelism); // offset ctl counts
2443	<	this.ctl = ((np << AC_SHIFT) & AC_MASK) \| ((np << TC_SHIFT) & TC_MASK);
2444	<	int pn = nextPoolId();
2445	<	StringBuilder sb = new StringBuilder("ForkJoinPool-");
2446	<	sb.append(Integer.toString(pn));
2579	<	sb.append("-worker-");
2580	<	this.workerNamePrefix = sb.toString();
2439	>	return parallelism;
2440	>	}
2441	>
2442	>	private static ForkJoinWorkerThreadFactory checkFactory
2443	>	(ForkJoinWorkerThreadFactory factory) {
2444	>	if (factory == null)
2445	>	throw new NullPointerException();
2446	>	return factory;
2447		}
2448
2449		/**
2450	<	* Constructor for common pool, suitable only for static initialization.
2451	<	* Basically the same as above, but uses smallest possible initial footprint.
2452	<	*/
2453	<	ForkJoinPool(int parallelism, long ctl,
2454	<	ForkJoinWorkerThreadFactory factory,
2455	<	Thread.UncaughtExceptionHandler handler) {
2456	<	this.config = parallelism;
2457	<	this.ctl = ctl;
2450	>	* Creates a {@code ForkJoinPool} with the given parameters, without
2451	>	* any security checks or parameter validation. Invoked directly by
2452	>	* makeCommonPool.
2453	>	*/
2454	>	private ForkJoinPool(int parallelism,
2455	>	ForkJoinWorkerThreadFactory factory,
2456	>	UncaughtExceptionHandler handler,
2457	>	int mode,
2458	>	String workerNamePrefix) {
2459	>	this.workerNamePrefix = workerNamePrefix;
2460		this.factory = factory;
2461		this.ueh = handler;
2462	<	this.workerNamePrefix = "ForkJoinPool.commonPool-worker-";
2462	>	this.mode = (short)mode;
2463	>	this.parallelism = (short)parallelism;
2464	>	long np = (long)(-parallelism); // offset ctl counts
2465	>	this.ctl = ((np << AC_SHIFT) & AC_MASK) \| ((np << TC_SHIFT) & TC_MASK);
2466		}
2467
2468		/**
2469	<	* Returns the common pool instance.
2469	>	* Returns the common pool instance. This pool is statically
2470	>	* constructed; its run state is unaffected by attempts to {@link
2471	>	* #shutdown} or {@link #shutdownNow}. However this pool and any
2472	>	* ongoing processing are automatically terminated upon program
2473	>	* {@link System#exit}. Any program that relies on asynchronous
2474	>	* task processing to complete before program termination should
2475	>	* invoke {@code commonPool().}{@link #awaitQuiescence awaitQuiescence},
2476	>	* before exit.
2477		*
2478		* @return the common pool instance
2479	+	* @since 1.8
2480		*/
2481		public static ForkJoinPool commonPool() {
2482	<	// assert commonPool != null : "static init error";
2483	<	return commonPool;
2482	>	// assert common != null : "static init error";
2483	>	return common;
2484		}
2485
2486		// Execution methods
#	Line 2657 \| Line 2536 \| public class ForkJoinPool extends Abstra
2536		if (task instanceof ForkJoinTask<?>) // avoid re-wrap
2537		job = (ForkJoinTask<?>) task;
2538		else
2539	<	job = new ForkJoinTask.AdaptedRunnableAction(task);
2539	>	job = new ForkJoinTask.RunnableExecuteAction(task);
2540		externalPush(job);
2541		}
2542
#	Line 2724 \| Line 2603 \| public class ForkJoinPool extends Abstra
2603		// In previous versions of this class, this method constructed
2604		// a task to run ForkJoinTask.invokeAll, but now external
2605		// invocation of multiple tasks is at least as efficient.
2606	<	List<ForkJoinTask<T>> fs = new ArrayList<ForkJoinTask<T>>(tasks.size());
2728	<	// Workaround needed because method wasn't declared with
2729	<	// wildcards in return type but should have been.
2730	<	@SuppressWarnings({"unchecked", "rawtypes"})
2731	<	List<Future<T>> futures = (List<Future<T>>) (List) fs;
2606	>	ArrayList<Future<T>> futures = new ArrayList<Future<T>>(tasks.size());
2607
2608		boolean done = false;
2609		try {
2610		for (Callable<T> t : tasks) {
2611		ForkJoinTask<T> f = new ForkJoinTask.AdaptedCallable<T>(t);
2612	+	futures.add(f);
2613		externalPush(f);
2738	–	fs.add(f);
2614		}
2615	<	for (ForkJoinTask<T> f : fs)
2616	<	f.quietlyJoin();
2615	>	for (int i = 0, size = futures.size(); i < size; i++)
2616	>	((ForkJoinTask<?>)futures.get(i)).quietlyJoin();
2617		done = true;
2618		return futures;
2619		} finally {
2620		if (!done)
2621	<	for (ForkJoinTask<T> f : fs)
2622	<	f.cancel(false);
2621	>	for (int i = 0, size = futures.size(); i < size; i++)
2622	>	futures.get(i).cancel(false);
2623		}
2624		}
2625
#	Line 2763 \| Line 2638 \| public class ForkJoinPool extends Abstra
2638		*
2639		* @return the handler, or {@code null} if none
2640		*/
2641	<	public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() {
2641	>	public UncaughtExceptionHandler getUncaughtExceptionHandler() {
2642		return ueh;
2643		}
2644
#	Line 2773 \| Line 2648 \| public class ForkJoinPool extends Abstra
2648		* @return the targeted parallelism level of this pool
2649		*/
2650		public int getParallelism() {
2651	<	return config & SMASK;
2651	>	int par;
2652	>	return ((par = parallelism) > 0) ? par : 1;
2653		}
2654
2655		/**
2656		* Returns the targeted parallelism level of the common pool.
2657		*
2658		* @return the targeted parallelism level of the common pool
2659	+	* @since 1.8
2660		*/
2661		public static int getCommonPoolParallelism() {
2662	<	return commonPoolParallelism;
2662	>	return commonParallelism;
2663		}
2664
2665		/**
#	Line 2794 \| Line 2671 \| public class ForkJoinPool extends Abstra
2671		* @return the number of worker threads
2672		*/
2673		public int getPoolSize() {
2674	<	return (config & SMASK) + (short)(ctl >>> TC_SHIFT);
2674	>	return parallelism + (short)(ctl >>> TC_SHIFT);
2675		}
2676
2677		/**
#	Line 2804 \| Line 2681 \| public class ForkJoinPool extends Abstra
2681		* @return {@code true} if this pool uses async mode
2682		*/
2683		public boolean getAsyncMode() {
2684	<	return (config >>> 16) == FIFO_QUEUE;
2684	>	return mode == FIFO_QUEUE;
2685		}
2686
2687		/**
#	Line 2835 \| Line 2712 \| public class ForkJoinPool extends Abstra
2712		* @return the number of active threads
2713		*/
2714		public int getActiveThreadCount() {
2715	<	int r = (config & SMASK) + (int)(ctl >> AC_SHIFT);
2715	>	int r = parallelism + (int)(ctl >> AC_SHIFT);
2716		return (r <= 0) ? 0 : r; // suppress momentarily negative values
2717		}
2718
#	Line 2851 \| Line 2728 \| public class ForkJoinPool extends Abstra
2728		* @return {@code true} if all threads are currently idle
2729		*/
2730		public boolean isQuiescent() {
2731	<	return (int)(ctl >> AC_SHIFT) + (config & SMASK) == 0;
2731	>	return parallelism + (int)(ctl >> AC_SHIFT) <= 0;
2732		}
2733
2734		/**
#	Line 3014 \| Line 2891 \| public class ForkJoinPool extends Abstra
2891		}
2892		}
2893		}
2894	<	int pc = (config & SMASK);
2894	>	int pc = parallelism;
2895		int tc = pc + (short)(c >>> TC_SHIFT);
2896		int ac = pc + (int)(c >> AC_SHIFT);
2897		if (ac < 0) // ignore transient negative
#	Line 3040 \| Line 2917 \| public class ForkJoinPool extends Abstra
2917		* Possibly initiates an orderly shutdown in which previously
2918		* submitted tasks are executed, but no new tasks will be
2919		* accepted. Invocation has no effect on execution state if this
2920	<	* is the {@link #commonPool}, and no additional effect if
2920	>	* is the {@link #commonPool()}, and no additional effect if
2921		* already shut down. Tasks that are in the process of being
2922		* submitted concurrently during the course of this method may or
2923		* may not be rejected.
#	Line 3058 \| Line 2935 \| public class ForkJoinPool extends Abstra
2935		/**
2936		* Possibly attempts to cancel and/or stop all tasks, and reject
2937		* all subsequently submitted tasks. Invocation has no effect on
2938	<	* execution state if this is the {@link #commonPool}, and no
2938	>	* execution state if this is the {@link #commonPool()}, and no
2939		* additional effect if already shut down. Otherwise, tasks that
2940		* are in the process of being submitted or executed concurrently
2941		* during the course of this method may or may not be
#	Line 3087 \| Line 2964 \| public class ForkJoinPool extends Abstra
2964		public boolean isTerminated() {
2965		long c = ctl;
2966		return ((c & STOP_BIT) != 0L &&
2967	<	(short)(c >>> TC_SHIFT) == -(config & SMASK));
2967	>	(short)(c >>> TC_SHIFT) + parallelism <= 0);
2968		}
2969
2970		/**
#	Line 3106 \| Line 2983 \| public class ForkJoinPool extends Abstra
2983		public boolean isTerminating() {
2984		long c = ctl;
2985		return ((c & STOP_BIT) != 0L &&
2986	<	(short)(c >>> TC_SHIFT) != -(config & SMASK));
2986	>	(short)(c >>> TC_SHIFT) + parallelism > 0);
2987		}
2988
2989		/**
#	Line 3121 \| Line 2998 \| public class ForkJoinPool extends Abstra
2998		/**
2999		* Blocks until all tasks have completed execution after a
3000		* shutdown request, or the timeout occurs, or the current thread
3001	<	* is interrupted, whichever happens first. Note that the {@link
3002	<	* #commonPool()} never terminates until program shutdown so
3003	<	* this method will always time out.
3001	>	* is interrupted, whichever happens first. Because the {@link
3002	>	* #commonPool()} never terminates until program shutdown, when
3003	>	* applied to the common pool, this method is equivalent to {@link
3004	>	* #awaitQuiescence(long, TimeUnit)} but always returns {@code false}.
3005		*
3006		* @param timeout the maximum time to wait
3007		* @param unit the time unit of the timeout argument
#	Line 3133 \| Line 3011 \| public class ForkJoinPool extends Abstra
3011		*/
3012		public boolean awaitTermination(long timeout, TimeUnit unit)
3013		throws InterruptedException {
3014	+	if (Thread.interrupted())
3015	+	throw new InterruptedException();
3016	+	if (this == common) {
3017	+	awaitQuiescence(timeout, unit);
3018	+	return false;
3019	+	}
3020		long nanos = unit.toNanos(timeout);
3021		if (isTerminated())
3022		return true;
3023	<	long startTime = System.nanoTime();
3024	<	boolean terminated = false;
3023	>	if (nanos <= 0L)
3024	>	return false;
3025	>	long deadline = System.nanoTime() + nanos;
3026		synchronized (this) {
3027	<	for (long waitTime = nanos, millis = 0L;;) {
3028	<	if (terminated = isTerminated() \|\|
3029	<	waitTime <= 0L \|\|
3030	<	(millis = unit.toMillis(waitTime)) <= 0L)
3027	>	for (;;) {
3028	>	if (isTerminated())
3029	>	return true;
3030	>	if (nanos <= 0L)
3031	>	return false;
3032	>	long millis = TimeUnit.NANOSECONDS.toMillis(nanos);
3033	>	wait(millis > 0L ? millis : 1L);
3034	>	nanos = deadline - System.nanoTime();
3035	>	}
3036	>	}
3037	>	}
3038	>
3039	>	/**
3040	>	* If called by a ForkJoinTask operating in this pool, equivalent
3041	>	* in effect to {@link ForkJoinTask#helpQuiesce}. Otherwise,
3042	>	* waits and/or attempts to assist performing tasks until this
3043	>	* pool {@link #isQuiescent} or the indicated timeout elapses.
3044	>	*
3045	>	* @param timeout the maximum time to wait
3046	>	* @param unit the time unit of the timeout argument
3047	>	* @return {@code true} if quiescent; {@code false} if the
3048	>	* timeout elapsed.
3049	>	*/
3050	>	public boolean awaitQuiescence(long timeout, TimeUnit unit) {
3051	>	long nanos = unit.toNanos(timeout);
3052	>	ForkJoinWorkerThread wt;
3053	>	Thread thread = Thread.currentThread();
3054	>	if ((thread instanceof ForkJoinWorkerThread) &&
3055	>	(wt = (ForkJoinWorkerThread)thread).pool == this) {
3056	>	helpQuiescePool(wt.workQueue);
3057	>	return true;
3058	>	}
3059	>	long startTime = System.nanoTime();
3060	>	WorkQueue[] ws;
3061	>	int r = 0, m;
3062	>	boolean found = true;
3063	>	while (!isQuiescent() && (ws = workQueues) != null &&
3064	>	(m = ws.length - 1) >= 0) {
3065	>	if (!found) {
3066	>	if ((System.nanoTime() - startTime) > nanos)
3067	>	return false;
3068	>	Thread.yield(); // cannot block
3069	>	}
3070	>	found = false;
3071	>	for (int j = (m + 1) << 2; j >= 0; --j) {
3072	>	ForkJoinTask<?> t; WorkQueue q; int b;
3073	>	if ((q = ws[r++ & m]) != null && (b = q.base) - q.top < 0) {
3074	>	found = true;
3075	>	if ((t = q.pollAt(b)) != null)
3076	>	t.doExec();
3077		break;
3078	<	wait(millis);
3148	<	waitTime = nanos - (System.nanoTime() - startTime);
3078	>	}
3079		}
3080		}
3081	<	return terminated;
3081	>	return true;
3082	>	}
3083	>
3084	>	/**
3085	>	* Waits and/or attempts to assist performing tasks indefinitely
3086	>	* until the {@link #commonPool()} {@link #isQuiescent}.
3087	>	*/
3088	>	static void quiesceCommonPool() {
3089	>	common.awaitQuiescence(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
3090		}
3091
3092		/**
#	Line 3160 \| Line 3098 \| public class ForkJoinPool extends Abstra
3098		* not necessary. Method {@code block} blocks the current thread
3099		* if necessary (perhaps internally invoking {@code isReleasable}
3100		* before actually blocking). These actions are performed by any
3101	<	* thread invoking {@link ForkJoinPool#managedBlock}. The
3102	<	* unusual methods in this API accommodate synchronizers that may,
3103	<	* but don't usually, block for long periods. Similarly, they
3101	>	* thread invoking {@link ForkJoinPool#managedBlock(ManagedBlocker)}.
3102	>	* The unusual methods in this API accommodate synchronizers that
3103	>	* may, but don't usually, block for long periods. Similarly, they
3104		* allow more efficient internal handling of cases in which
3105		* additional workers may be, but usually are not, needed to
3106		* ensure sufficient parallelism. Toward this end,
#	Line 3220 \| Line 3158 \| public class ForkJoinPool extends Abstra
3158
3159		/**
3160		* Returns {@code true} if blocking is unnecessary.
3161	+	* @return {@code true} if blocking is unnecessary
3162		*/
3163		boolean isReleasable();
3164		}
#	Line 3249 \| Line 3188 \| public class ForkJoinPool extends Abstra
3188		Thread t = Thread.currentThread();
3189		if (t instanceof ForkJoinWorkerThread) {
3190		ForkJoinPool p = ((ForkJoinWorkerThread)t).pool;
3191	<	while (!blocker.isReleasable()) { // variant of helpSignal
3192	<	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 && 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	<	}
3265	<	}
3266	<	if (p.tryCompensate()) {
3191	>	while (!blocker.isReleasable()) {
3192	>	if (p.tryCompensate(p.ctl)) {
3193		try {
3194		do {} while (!blocker.isReleasable() &&
3195		!blocker.block());
#	Line 3301 \| Line 3227 \| public class ForkJoinPool extends Abstra
3227		private static final long STEALCOUNT;
3228		private static final long PLOCK;
3229		private static final long INDEXSEED;
3230	+	private static final long QBASE;
3231		private static final long QLOCK;
3232
3233		static {
3234	<	int s; // initialize field offsets for CAS etc
3234	>	// initialize field offsets for CAS etc
3235		try {
3236		U = getUnsafe();
3237		Class<?> k = ForkJoinPool.class;
#	Line 3320 \| Line 3247 \| public class ForkJoinPool extends Abstra
3247		PARKBLOCKER = U.objectFieldOffset
3248		(tk.getDeclaredField("parkBlocker"));
3249		Class<?> wk = WorkQueue.class;
3250	+	QBASE = U.objectFieldOffset
3251	+	(wk.getDeclaredField("base"));
3252		QLOCK = U.objectFieldOffset
3253		(wk.getDeclaredField("qlock"));
3254		Class<?> ak = ForkJoinTask[].class;
3255		ABASE = U.arrayBaseOffset(ak);
3256	<	s = U.arrayIndexScale(ak);
3257	<	ASHIFT = 31 - Integer.numberOfLeadingZeros(s);
3256	>	int scale = U.arrayIndexScale(ak);
3257	>	if ((scale & (scale - 1)) != 0)
3258	>	throw new Error("data type scale not a power of two");
3259	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
3260		} catch (Exception e) {
3261		throw new Error(e);
3262		}
3332	–	if ((s & (s-1)) != 0)
3333	–	throw new Error("data type scale not a power of two");
3263
3264		submitters = new ThreadLocal<Submitter>();
3265	<	ForkJoinWorkerThreadFactory fac = defaultForkJoinWorkerThreadFactory =
3265	>	defaultForkJoinWorkerThreadFactory =
3266		new DefaultForkJoinWorkerThreadFactory();
3267		modifyThreadPermission = new RuntimePermission("modifyThread");
3268
3269	<	/*
3270	<	* Establish common pool parameters. For extra caution,
3271	<	* computations to set up common pool state are here; the
3272	<	* constructor just assigns these values to fields.
3273	<	*/
3269	>	common = java.security.AccessController.doPrivileged
3270	>	(new java.security.PrivilegedAction<ForkJoinPool>() {
3271	>	public ForkJoinPool run() { return makeCommonPool(); }});
3272	>	int par = common.parallelism; // report 1 even if threads disabled
3273	>	commonParallelism = par > 0 ? par : 1;
3274	>	}
3275
3276	<	int par = 0;
3277	<	Thread.UncaughtExceptionHandler handler = null;
3278	<	try { // TBD: limit or report ignored exceptions?
3276	>	/**
3277	>	* Creates and returns the common pool, respecting user settings
3278	>	* specified via system properties.
3279	>	*/
3280	>	private static ForkJoinPool makeCommonPool() {
3281	>	int parallelism = -1;
3282	>	ForkJoinWorkerThreadFactory factory
3283	>	= defaultForkJoinWorkerThreadFactory;
3284	>	UncaughtExceptionHandler handler = null;
3285	>	try { // ignore exceptions in accessing/parsing properties
3286		String pp = System.getProperty
3287		("java.util.concurrent.ForkJoinPool.common.parallelism");
3351	–	String hp = System.getProperty
3352	–	("java.util.concurrent.ForkJoinPool.common.exceptionHandler");
3288		String fp = System.getProperty
3289		("java.util.concurrent.ForkJoinPool.common.threadFactory");
3290	+	String hp = System.getProperty
3291	+	("java.util.concurrent.ForkJoinPool.common.exceptionHandler");
3292	+	if (pp != null)
3293	+	parallelism = Integer.parseInt(pp);
3294		if (fp != null)
3295	<	fac = ((ForkJoinWorkerThreadFactory)ClassLoader.
3296	<	getSystemClassLoader().loadClass(fp).newInstance());
3295	>	factory = ((ForkJoinWorkerThreadFactory)ClassLoader.
3296	>	getSystemClassLoader().loadClass(fp).newInstance());
3297		if (hp != null)
3298	<	handler = ((Thread.UncaughtExceptionHandler)ClassLoader.
3298	>	handler = ((UncaughtExceptionHandler)ClassLoader.
3299		getSystemClassLoader().loadClass(hp).newInstance());
3361	–	if (pp != null)
3362	–	par = Integer.parseInt(pp);
3300		} catch (Exception ignore) {
3301		}
3302
3303	<	if (par <= 0)
3304	<	par = Runtime.getRuntime().availableProcessors();
3305	<	if (par > MAX_CAP)
3306	<	par = MAX_CAP;
3307	<	commonPoolParallelism = par;
3308	<	long np = (long)(-par); // precompute initial ctl value
3309	<	long ct = ((np << AC_SHIFT) & AC_MASK) \| ((np << TC_SHIFT) & TC_MASK);
3373	<
3374	<	commonPool = new ForkJoinPool(par, ct, fac, handler);
3303	>	if (parallelism < 0 && // default 1 less than #cores
3304	>	(parallelism = Runtime.getRuntime().availableProcessors() - 1) < 0)
3305	>	parallelism = 0;
3306	>	if (parallelism > MAX_CAP)
3307	>	parallelism = MAX_CAP;
3308	>	return new ForkJoinPool(parallelism, factory, handler, LIFO_QUEUE,
3309	>	"ForkJoinPool.commonPool-worker-");
3310		}
3311
3312		/**
#	Line 3384 \| Line 3319 \| public class ForkJoinPool extends Abstra
3319		private static sun.misc.Unsafe getUnsafe() {
3320		try {
3321		return sun.misc.Unsafe.getUnsafe();
3322	<	} catch (SecurityException se) {
3323	<	try {
3324	<	return java.security.AccessController.doPrivileged
3325	<	(new java.security
3326	<	.PrivilegedExceptionAction<sun.misc.Unsafe>() {
3327	<	public sun.misc.Unsafe run() throws Exception {
3328	<	java.lang.reflect.Field f = sun.misc
3329	<	.Unsafe.class.getDeclaredField("theUnsafe");
3330	<	f.setAccessible(true);
3331	<	return (sun.misc.Unsafe) f.get(null);
3332	<	}});
3333	<	} catch (java.security.PrivilegedActionException e) {
3334	<	throw new RuntimeException("Could not initialize intrinsics",
3335	<	e.getCause());
3336	<	}
3322	>	} catch (SecurityException tryReflectionInstead) {}
3323	>	try {
3324	>	return java.security.AccessController.doPrivileged
3325	>	(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
3326	>	public sun.misc.Unsafe run() throws Exception {
3327	>	Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class;
3328	>	for (java.lang.reflect.Field f : k.getDeclaredFields()) {
3329	>	f.setAccessible(true);
3330	>	Object x = f.get(null);
3331	>	if (k.isInstance(x))
3332	>	return k.cast(x);
3333	>	}
3334	>	throw new NoSuchFieldError("the Unsafe");
3335	>	}});
3336	>	} catch (java.security.PrivilegedActionException e) {
3337	>	throw new RuntimeException("Could not initialize intrinsics",
3338	>	e.getCause());
3339		}
3340		}
3404	–
3341		}

Diff Legend

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

Comparing jsr166/src/jsr166e/ForkJoinPool.java (file contents): Revision 1.31 by dl, Sat Dec 15 22:15:47 2012 UTC vs. Revision 1.60 by jsr166, Wed Jun 19 16:36:45 2013 UTC

Diff Legend

Comparing jsr166/src/jsr166e/ForkJoinPool.java (file contents):
Revision 1.31 by dl, Sat Dec 15 22:15:47 2012 UTC vs.
Revision 1.60 by jsr166, Wed Jun 19 16:36:45 2013 UTC