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

Comparing jsr166/src/jsr166e/ForkJoinPool.java (file contents):
Revision 1.7 by dl, Sun Oct 28 22:35:45 2012 UTC vs.
Revision 1.45 by jsr166, Wed Jan 9 02:51:36 2013 UTC

#	Line 11 \| Line 11 \| import java.util.Arrays;
11		import java.util.Collection;
12		import java.util.Collections;
13		import java.util.List;
14	–	import java.util.Random;
14		import java.util.concurrent.AbstractExecutorService;
15		import java.util.concurrent.Callable;
16		import java.util.concurrent.ExecutorService;
17		import java.util.concurrent.Future;
18		import java.util.concurrent.RejectedExecutionException;
19		import java.util.concurrent.RunnableFuture;
21	–	import java.util.concurrent.ThreadLocalRandom;
20		import java.util.concurrent.TimeUnit;
23	–	import java.util.concurrent.atomic.AtomicInteger;
24	–	import java.util.concurrent.atomic.AtomicLong;
25	–	import java.util.concurrent.locks.AbstractQueuedSynchronizer;
26	–	import java.util.concurrent.locks.Condition;
21
22		/**
23		* An {@link ExecutorService} for running {@link ForkJoinTask}s.
#	Line 43 \| Line 37 \| import java.util.concurrent.locks.Condit
37		* ForkJoinPool}s may also be appropriate for use with event-style
38		* tasks that are never joined.
39		*
40	<	* <p>A static {@link #commonPool} is available and appropriate for
41	<	* most applications. The common pool is constructed upon first
42	<	* access, or upon usage by any ForkJoinTask that is not explictly
43	<	* submitted to a specified pool. Using the common pool normally
44	<	* reduces resource usage (its threads are slowly reclaimed during
45	<	* periods of non-use, and reinstated upon subsequent use). The
52	<	* common pool is by default constructed with default parameters, but
53	<	* these may be controlled by setting any or all of the three
54	<	* properties {@code
55	<	* java.util.concurrent.ForkJoinPool.common.{parallelism,
56	<	* threadFactory, exceptionHandler}}.
40	>	* <p>A static {@link #commonPool()} is available and appropriate for
41	>	* most applications. The common pool is used by any ForkJoinTask that
42	>	* is not explicitly submitted to a specified pool. Using the common
43	>	* pool normally reduces resource usage (its threads are slowly
44	>	* reclaimed during periods of non-use, and reinstated upon subsequent
45	>	* use).
46		*
47		* <p>For applications that require separate or custom pools, a {@code
48		* ForkJoinPool} may be constructed with a given target parallelism
#	Line 62 \| Line 51 \| import java.util.concurrent.locks.Condit
51		* dynamically adding, suspending, or resuming internal worker
52		* threads, even if some tasks are stalled waiting to join
53		* others. However, no such adjustments are guaranteed in the face of
54	<	* blocked IO or other unmanaged synchronization. The nested {@link
54	>	* blocked I/O or other unmanaged synchronization. The nested {@link
55		* ManagedBlocker} interface enables extension of the kinds of
56		* synchronization accommodated.
57		*
#	Line 73 \| Line 62 \| import java.util.concurrent.locks.Condit
62		* {@link #toString} returns indications of pool state in a
63		* convenient form for informal monitoring.
64		*
65	<	* <p> As is the case with other ExecutorServices, there are three
65	>	* <p>As is the case with other ExecutorServices, there are three
66		* main task execution methods summarized in the following table.
67		* These are designed to be used primarily by clients not already
68		* engaged in fork/join computations in the current pool. The main
#	Line 108 \| Line 97 \| import java.util.concurrent.locks.Condit
97		* </tr>
98		* </table>
99		*
100	+	* <p>The common pool is by default constructed with default
101	+	* parameters, but these may be controlled by setting three {@link
102	+	* System#getProperty system properties} with prefix {@code
103	+	* java.util.concurrent.ForkJoinPool.common}: {@code parallelism} --
104	+	* an integer greater than zero, {@code threadFactory} -- the class
105	+	* name of a {@link ForkJoinWorkerThreadFactory}, and {@code
106	+	* exceptionHandler} -- the class name of a {@link
107	+	* java.lang.Thread.UncaughtExceptionHandler
108	+	* Thread.UncaughtExceptionHandler}. Upon any error in establishing
109	+	* these settings, default parameters are used.
110	+	*
111		* <p><b>Implementation notes</b>: This implementation restricts the
112		* maximum number of running threads to 32767. Attempts to create
113		* pools with greater than the maximum number result in
#	Line 194 \| Line 194 \| public class ForkJoinPool extends Abstra
194		* WorkQueues are also used in a similar way for tasks submitted
195		* to the pool. We cannot mix these tasks in the same queues used
196		* for work-stealing (this would contaminate lifo/fifo
197	<	* processing). Instead, we loosely associate submission queues
197	>	* processing). Instead, we randomly associate submission queues
198		* with submitting threads, using a form of hashing. The
199		* ThreadLocal Submitter class contains a value initially used as
200		* a hash code for choosing existing queues, but may be randomly
201		* repositioned upon contention with other submitters. In
202	<	* essence, submitters act like workers except that they never
203	<	* take tasks, and they are multiplexed on to a finite number of
204	<	* shared work queues. However, classes are set up so that future
205	<	* extensions could allow submitters to optionally help perform
206	<	* tasks as well. Insertion of tasks in shared mode requires a
207	<	* lock (mainly to protect in the case of resizing) but we use
208	<	* only a simple spinlock (using bits in field runState), because
209	<	* submitters encountering a busy queue move on to try or create
210	<	* other queues -- they block only when creating and registering
211	<	* new queues.
202	>	* essence, submitters act like workers except that they are
203	>	* restricted to executing local tasks that they submitted (or in
204	>	* the case of CountedCompleters, others with the same root task).
205	>	* However, because most shared/external queue operations are more
206	>	* expensive than internal, and because, at steady state, external
207	>	* submitters will compete for CPU with workers, ForkJoinTask.join
208	>	* and related methods disable them from repeatedly helping to
209	>	* process tasks if all workers are active. Insertion of tasks in
210	>	* shared mode requires a lock (mainly to protect in the case of
211	>	* resizing) but we use only a simple spinlock (using bits in
212	>	* field qlock), because submitters encountering a busy queue move
213	>	* on to try or create other queues -- they block only when
214	>	* creating and registering new queues.
215		*
216		* Management
217		* ==========
#	Line 230 \| Line 233 \| public class ForkJoinPool extends Abstra
233		* and their negations (used for thresholding) to fit into 16bit
234		* fields.
235		*
236	<	* Field "runState" contains 32 bits needed to register and
237	<	* deregister WorkQueues, as well as to enable shutdown. It is
238	<	* only modified under a lock (normally briefly held, but
239	<	* occasionally protecting allocations and resizings) but even
240	<	* when locked remains available to check consistency.
236	>	* Field "plock" is a form of sequence lock with a saturating
237	>	* shutdown bit (similarly for per-queue "qlocks"), mainly
238	>	* protecting updates to the workQueues array, as well as to
239	>	* enable shutdown. When used as a lock, it is normally only very
240	>	* briefly held, so is nearly always available after at most a
241	>	* brief spin, but we use a monitor-based backup strategy to
242	>	* block when needed.
243		*
244		* Recording WorkQueues. WorkQueues are recorded in the
245	<	* "workQueues" array that is created upon pool construction and
246	<	* expanded if necessary. Updates to the array while recording
247	<	* new workers and unrecording terminated ones are protected from
248	<	* each other by a lock but the array is otherwise concurrently
249	<	* readable, and accessed directly. To simplify index-based
250	<	* operations, the array size is always a power of two, and all
251	<	* readers must tolerate null slots. Shared (submission) queues
252	<	* are at even indices, worker queues at odd indices. Grouping
253	<	* them together in this way simplifies and speeds up task
254	<	* scanning.
245	>	* "workQueues" array that is created upon first use and expanded
246	>	* if necessary. Updates to the array while recording new workers
247	>	* and unrecording terminated ones are protected from each other
248	>	* by a lock but the array is otherwise concurrently readable, and
249	>	* accessed directly. To simplify index-based operations, the
250	>	* array size is always a power of two, and all readers must
251	>	* tolerate null slots. Worker queues are at odd indices. Shared
252	>	* (submission) queues are at even indices, up to a maximum of 64
253	>	* slots, to limit growth even if array needs to expand to add
254	>	* more workers. Grouping them together in this way simplifies and
255	>	* speeds up task scanning.
256		*
257		* All worker thread creation is on-demand, triggered by task
258		* submissions, replacement of terminated workers, and/or
#	Line 307 \| Line 313 \| public class ForkJoinPool extends Abstra
313		*
314		* Signalling. We create or wake up workers only when there
315		* appears to be at least one task they might be able to find and
316	<	* execute. When a submission is added or another worker adds a
317	<	* task to a queue that previously had fewer than two tasks, they
318	<	* signal waiting workers (or trigger creation of new ones if
319	<	* fewer than the given parallelism level -- see signalWork).
320	<	* These primary signals are buttressed by signals during rescans;
321	<	* together these cover the signals needed in cases when more
322	<	* tasks are pushed but untaken, and improve performance compared
323	<	* to having one thread wake up all workers.
316	>	* execute. However, many other threads may notice the same task
317	>	* and each signal to wake up a thread that might take it. So in
318	>	* general, pools will be over-signalled. When a submission is
319	>	* added or another worker adds a task to a queue that has fewer
320	>	* than two tasks, they signal waiting workers (or trigger
321	>	* creation of new ones if fewer than the given parallelism level
322	>	* -- signalWork), and may leave a hint to the unparked worker to
323	>	* help signal others upon wakeup). These primary signals are
324	>	* buttressed by others (see method helpSignal) whenever other
325	>	* threads scan for work or do not have a task to process. On
326	>	* most platforms, signalling (unpark) overhead time is noticeably
327	>	* long, and the time between signalling a thread and it actually
328	>	* making progress can be very noticeably long, so it is worth
329	>	* offloading these delays from critical paths as much as
330	>	* possible.
331		*
332		* Trimming workers. To release resources after periods of lack of
333		* use, a worker starting to wait when the pool is quiescent will
#	Line 325 \| Line 338 \| public class ForkJoinPool extends Abstra
338		* periods of non-use.
339		*
340		* Shutdown and Termination. A call to shutdownNow atomically sets
341	<	* a runState bit and then (non-atomically) sets each worker's
342	<	* runState status, cancels all unprocessed tasks, and wakes up
341	>	* a plock bit and then (non-atomically) sets each worker's
342	>	* qlock status, cancels all unprocessed tasks, and wakes up
343		* all waiting workers. Detecting whether termination should
344		* commence after a non-abrupt shutdown() call requires more work
345		* and bookkeeping. We need consensus about quiescence (i.e., that
#	Line 354 \| Line 367 \| public class ForkJoinPool extends Abstra
367		* method tryCompensate() may create or re-activate a spare
368		* thread to compensate for blocked joiners until they unblock.
369		*
370	<	* A third form (implemented in tryRemoveAndExec and
371	<	* tryPollForAndExec) amounts to helping a hypothetical
372	<	* compensator: If we can readily tell that a possible action of a
373	<	* compensator is to steal and execute the task being joined, the
374	<	* joining thread can do so directly, without the need for a
375	<	* compensation thread (although at the expense of larger run-time
376	<	* stacks, but the tradeoff is typically worthwhile).
370	>	* A third form (implemented in tryRemoveAndExec) amounts to
371	>	* helping a hypothetical compensator: If we can readily tell that
372	>	* a possible action of a compensator is to steal and execute the
373	>	* task being joined, the joining thread can do so directly,
374	>	* without the need for a compensation thread (although at the
375	>	* expense of larger run-time stacks, but the tradeoff is
376	>	* typically worthwhile).
377		*
378		* The ManagedBlocker extension API can't use helping so relies
379		* only on compensation in method awaitBlocker.
#	Line 382 \| Line 395 \| public class ForkJoinPool extends Abstra
395		* steals, rather than use per-task bookkeeping. This sometimes
396		* requires a linear scan of workQueues array to locate stealers,
397		* but often doesn't because stealers leave hints (that may become
398	<	* stale/wrong) of where to locate them. A stealHint is only a
399	<	* hint because a worker might have had multiple steals and the
400	<	* hint records only one of them (usually the most current).
401	<	* Hinting isolates cost to when it is needed, rather than adding
402	<	* to per-task overhead. (2) It is "shallow", ignoring nesting
403	<	* and potentially cyclic mutual steals. (3) It is intentionally
398	>	* stale/wrong) of where to locate them. It is only a hint
399	>	* because a worker might have had multiple steals and the hint
400	>	* records only one of them (usually the most current). Hinting
401	>	* isolates cost to when it is needed, rather than adding to
402	>	* per-task overhead. (2) It is "shallow", ignoring nesting and
403	>	* potentially cyclic mutual steals. (3) It is intentionally
404		* racy: field currentJoin is updated only while actively joining,
405		* which means that we miss links in the chain during long-lived
406		* tasks, GC stalls etc (which is OK since blocking in such cases
#	Line 395 \| Line 408 \| public class ForkJoinPool extends Abstra
408		* to find work (see MAX_HELP) and fall back to suspending the
409		* worker and if necessary replacing it with another.
410		*
411	+	* Helping actions for CountedCompleters are much simpler: Method
412	+	* helpComplete can take and execute any task with the same root
413	+	* as the task being waited on. However, this still entails some
414	+	* traversal of completer chains, so is less efficient than using
415	+	* CountedCompleters without explicit joins.
416	+	*
417		* It is impossible to keep exactly the target parallelism number
418		* of threads running at any given time. Determining the
419		* existence of conservatively safe helping targets, the
#	Line 416 \| Line 435 \| public class ForkJoinPool extends Abstra
435		* intractable) game with an opponent that may choose the worst
436		* (for us) active thread to stall at any time. We take several
437		* precautions to bound losses (and thus bound gains), mainly in
438	<	* methods tryCompensate and awaitJoin: (1) We only try
439	<	* compensation after attempting enough helping steps (measured
440	<	* via counting and timing) that we have already consumed the
441	<	* estimated cost of creating and activating a new thread. (2) We
442	<	* allow up to 50% of threads to be blocked before initially
443	<	* adding any others, and unless completely saturated, check that
444	<	* some work is available for a new worker before adding. Also, we
445	<	* create up to only 50% more threads until entering a mode that
446	<	* only adds a thread if all others are possibly blocked. All
447	<	* together, this means that we might be half as fast to react,
448	<	* and create half as many threads as possible in the ideal case,
449	<	* but present vastly fewer anomalies in all other cases compared
450	<	* to both more aggressive and more conservative alternatives.
451	<	*
452	<	* Style notes: There is a lot of representation-level coupling
453	<	* among classes ForkJoinPool, ForkJoinWorkerThread, and
454	<	* ForkJoinTask. The fields of WorkQueue maintain data structures
455	<	* managed by ForkJoinPool, so are directly accessed. There is
456	<	* little point trying to reduce this, since any associated future
457	<	* changes in representations will need to be accompanied by
458	<	* algorithmic changes anyway. Several methods intrinsically
459	<	* sprawl because they must accumulate sets of consistent reads of
460	<	* volatiles held in local variables. Methods signalWork() and
461	<	* scan() are the main bottlenecks, so are especially heavily
438	>	* methods tryCompensate and awaitJoin.
439	>	*
440	>	* Common Pool
441	>	* ===========
442	>	*
443	>	* The static common Pool always exists after static
444	>	* initialization. Since it (or any other created pool) need
445	>	* never be used, we minimize initial construction overhead and
446	>	* footprint to the setup of about a dozen fields, with no nested
447	>	* allocation. Most bootstrapping occurs within method
448	>	* fullExternalPush during the first submission to the pool.
449	>	*
450	>	* When external threads submit to the common pool, they can
451	>	* perform some subtask processing (see externalHelpJoin and
452	>	* related methods). We do not need to record whether these
453	>	* submissions are to the common pool -- if not, externalHelpJoin
454	>	* returns quickly (at the most helping to signal some common pool
455	>	* workers). These submitters would otherwise be blocked waiting
456	>	* for completion, so the extra effort (with liberally sprinkled
457	>	* task status checks) in inapplicable cases amounts to an odd
458	>	* form of limited spin-wait before blocking in ForkJoinTask.join.
459	>	*
460	>	* Style notes
461	>	* ===========
462	>	*
463	>	* There is a lot of representation-level coupling among classes
464	>	* ForkJoinPool, ForkJoinWorkerThread, and ForkJoinTask. The
465	>	* fields of WorkQueue maintain data structures managed by
466	>	* ForkJoinPool, so are directly accessed. There is little point
467	>	* trying to reduce this, since any associated future changes in
468	>	* representations will need to be accompanied by algorithmic
469	>	* changes anyway. Several methods intrinsically sprawl because
470	>	* they must accumulate sets of consistent reads of volatiles held
471	>	* in local variables. Methods signalWork() and scan() are the
472	>	* main bottlenecks, so are especially heavily
473		* micro-optimized/mangled. There are lots of inline assignments
474		* (of form "while ((local = field) != 0)") which are usually the
475		* simplest way to ensure the required read orderings (which are
#	Line 447 \| Line 477 \| public class ForkJoinPool extends Abstra
477		* declarations of these locals at the heads of methods or blocks.
478		* There are several occurrences of the unusual "do {} while
479		* (!cas...)" which is the simplest way to force an update of a
480	<	* CAS'ed variable. There are also other coding oddities that help
480	>	* CAS'ed variable. There are also other coding oddities (including
481	>	* several unnecessary-looking hoisted null checks) that help
482		* some methods perform reasonably even when interpreted (not
483		* compiled).
484		*
#	Line 496 \| Line 527 \| public class ForkJoinPool extends Abstra
527		* Default ForkJoinWorkerThreadFactory implementation; creates a
528		* new ForkJoinWorkerThread.
529		*/
530	<	static class DefaultForkJoinWorkerThreadFactory
530	>	static final class DefaultForkJoinWorkerThreadFactory
531		implements ForkJoinWorkerThreadFactory {
532	<	public ForkJoinWorkerThread newThread(ForkJoinPool pool) {
532	>	public final ForkJoinWorkerThread newThread(ForkJoinPool pool) {
533		return new ForkJoinWorkerThread(pool);
534		}
535		}
536
537		/**
538	<	* A simple non-reentrant lock used for exclusion when managing
539	<	* queues and workers. We use a custom lock so that we can readily
540	<	* probe lock state in constructions that check among alternative
541	<	* actions. The lock is normally only very briefly held, and
542	<	* sometimes treated as a spinlock, but other usages block to
543	<	* reduce overall contention in those cases where locked code
544	<	* bodies perform allocation/resizing.
545	<	*/
546	<	static final class Mutex extends AbstractQueuedSynchronizer {
547	<	public final boolean tryAcquire(int ignore) {
548	<	return compareAndSetState(0, 1);
549	<	}
550	<	public final boolean tryRelease(int ignore) {
551	<	setState(0);
552	<	return true;
553	<	}
554	<	public final void lock() { acquire(0); }
524	<	public final void unlock() { release(0); }
525	<	public final boolean isHeldExclusively() { return getState() == 1; }
526	<	public final Condition newCondition() { return new ConditionObject(); }
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		/**
#	Line 533 \| Line 561 \| public class ForkJoinPool extends Abstra
561		* actually do anything beyond having a unique identity.
562		*/
563		static final class EmptyTask extends ForkJoinTask<Void> {
564	+	private static final long serialVersionUID = -7721805057305804111L;
565		EmptyTask() { status = ForkJoinTask.NORMAL; } // force done
566		public final Void getRawResult() { return null; }
567		public final void setRawResult(Void x) {}
#	Line 553 \| Line 582 \| public class ForkJoinPool extends Abstra
582		*
583		* Field "top" is the index (mod array.length) of the next queue
584		* slot to push to or pop from. It is written only by owner thread
585	<	* for push, or under lock for trySharedPush, and accessed by
586	<	* other threads only after reading (volatile) base. Both top and
587	<	* base are allowed to wrap around on overflow, but (top - base)
588	<	* (or more commonly -(base - top) to force volatile read of base
589	<	* before top) still estimates size.
585	>	* for push, or under lock for external/shared push, and accessed
586	>	* by other threads only after reading (volatile) base. Both top
587	>	* and base are allowed to wrap around on overflow, but (top -
588	>	* base) (or more commonly -(base - top) to force volatile read of
589	>	* base before top) still estimates size. The lock ("qlock") is
590	>	* forced to -1 on termination, causing all further lock attempts
591	>	* to fail. (Note: we don't need CAS for termination state because
592	>	* upon pool shutdown, all shared-queues will stop being used
593	>	* anyway.) Nearly all lock bodies are set up so that exceptions
594	>	* within lock bodies are "impossible" (modulo JVM errors that
595	>	* would cause failure anyway.)
596		*
597		* The array slots are read and written using the emulation of
598		* volatiles/atomics provided by Unsafe. Insertions must in
599		* general use putOrderedObject as a form of releasing store to
600		* ensure that all writes to the task object are ordered before
601	<	* its publication in the queue. (Although we can avoid one case
602	<	* of this when locked in trySharedPush.) All removals entail a
603	<	* CAS to null. The array is always a power of two. To ensure
604	<	* safety of Unsafe array operations, all accesses perform
570	<	* explicit null checks and implicit bounds checks via
571	<	* power-of-two masking.
601	>	* its publication in the queue. All removals entail a CAS to
602	>	* null. The array is always a power of two. To ensure safety of
603	>	* Unsafe array operations, all accesses perform explicit null
604	>	* checks and implicit bounds checks via power-of-two masking.
605		*
606		* In addition to basic queuing support, this class contains
607		* fields described elsewhere to control execution. It turns out
608	<	* to work better memory-layout-wise to include them in this
609	<	* class rather than a separate class.
608	>	* to work better memory-layout-wise to include them in this class
609	>	* rather than a separate class.
610		*
611		* Performance on most platforms is very sensitive to placement of
612		* instances of both WorkQueues and their arrays -- we absolutely
#	Line 587 \| Line 620 \| public class ForkJoinPool extends Abstra
620		* trades off slightly slower average field access for the sake of
621		* avoiding really bad worst-case access. (Until better JVM
622		* support is in place, this padding is dependent on transient
623	<	* properties of JVM field layout rules.) We also take care in
623	>	* properties of JVM field layout rules.) We also take care in
624		* allocating, sizing and resizing the array. Non-shared queue
625	<	* arrays are initialized (via method growArray) by workers before
626	<	* use. Others are allocated on first use.
625	>	* arrays are initialized by workers before use. Others are
626	>	* allocated on first use.
627		*/
628		static final class WorkQueue {
629		/**
#	Line 613 \| Line 646 \| public class ForkJoinPool extends Abstra
646		*/
647		static final int MAXIMUM_QUEUE_CAPACITY = 1 << 26; // 64M
648
649	<	volatile long totalSteals; // cumulative number of steals
649	>	// Heuristic padding to ameliorate unfortunate memory placements
650	>	volatile long pad00, pad01, pad02, pad03, pad04, pad05, pad06;
651	>
652		int seed; // for random scanning; initialize nonzero
653		volatile int eventCount; // encoded inactivation count; < 0 if inactive
654		int nextWait; // encoded record of next event waiter
655	<	int rescans; // remaining scans until block
621	<	int nsteals; // top-level task executions since last idle
622	<	final int mode; // lifo, fifo, or shared
655	>	int hint; // steal or signal hint (index)
656		int poolIndex; // index of this queue in pool (or 0)
657	<	int stealHint; // index of most recent known stealer
658	<	volatile int runState; // 1: locked, -1: terminate; else 0
657	>	final int mode; // 0: lifo, > 0: fifo, < 0: shared
658	>	int nsteals; // number of steals
659	>	volatile int qlock; // 1: locked, -1: terminate; else 0
660		volatile int base; // index of next slot for poll
661		int top; // index of next slot for push
662		ForkJoinTask<?>[] array; // the elements (initially unallocated)
#	Line 631 \| Line 665 \| public class ForkJoinPool extends Abstra
665		volatile Thread parker; // == owner during call to park; else null
666		volatile ForkJoinTask<?> currentJoin; // task being joined in awaitJoin
667		ForkJoinTask<?> currentSteal; // current non-local task being executed
634	–	// Heuristic padding to ameliorate unfortunate memory placements
635	–	Object p00, p01, p02, p03, p04, p05, p06, p07;
636	–	Object p08, p09, p0a, p0b, p0c, p0d, p0e;
668
669	<	WorkQueue(ForkJoinPool pool, ForkJoinWorkerThread owner, int mode) {
670	<	this.mode = mode;
669	>	volatile Object pad10, pad11, pad12, pad13, pad14, pad15, pad16, pad17;
670	>	volatile Object pad18, pad19, pad1a, pad1b, pad1c, pad1d;
671	>
672	>	WorkQueue(ForkJoinPool pool, ForkJoinWorkerThread owner, int mode,
673	>	int seed) {
674		this.pool = pool;
675		this.owner = owner;
676	+	this.mode = mode;
677	+	this.seed = seed;
678		// Place indices in the center of array (that is not yet allocated)
679		base = top = INITIAL_QUEUE_CAPACITY >>> 1;
680		}
#	Line 651 \| Line 687 \| public class ForkJoinPool extends Abstra
687		return (n >= 0) ? 0 : -n; // ignore transient negative
688		}
689
690	<	/**
690	>	/**
691		* Provides a more accurate estimate of whether this queue has
692		* any tasks than does queueSize, by checking whether a
693		* near-empty queue has at least one unclaimed task.
#	Line 663 \| Line 699 \| public class ForkJoinPool extends Abstra
699		(n == -1 &&
700		((a = array) == null \|\|
701		(m = a.length - 1) < 0 \|\|
702	<	U.getObjectVolatile
703	<	(a, ((m & (s - 1)) << ASHIFT) + ABASE) == null)));
702	>	U.getObject
703	>	(a, (long)((m & (s - 1)) << ASHIFT) + ABASE) == null)));
704		}
705
706		/**
707	<	* Pushes a task. Call only by owner in unshared queues.
707	>	* Pushes a task. Call only by owner in unshared queues. (The
708	>	* shared-queue version is embedded in method externalPush.)
709		*
710		* @param task the task. Caller must ensure non-null.
711		* @throw RejectedExecutionException if array cannot be resized
#	Line 677 \| Line 714 \| public class ForkJoinPool extends Abstra
714		ForkJoinTask<?>[] a; ForkJoinPool p;
715		int s = top, m, n;
716		if ((a = array) != null) { // ignore if queue removed
717	<	U.putOrderedObject
718	<	(a, (((m = a.length - 1) & s) << ASHIFT) + ABASE, task);
717	>	int j = (((m = a.length - 1) & s) << ASHIFT) + ABASE;
718	>	U.putOrderedObject(a, j, task);
719		if ((n = (top = s + 1) - base) <= 2) {
720		if ((p = pool) != null)
721	<	p.signalWork();
721	>	p.signalWork(this);
722		}
723		else if (n >= m)
724	<	growArray(true);
724	>	growArray();
725		}
726		}
727
728	<	/**
729	<	* Pushes a task if lock is free and array is either big
730	<	* enough or can be resized to be big enough.
731	<	*
695	<	* @param task the task. Caller must ensure non-null.
696	<	* @return true if submitted
728	>	/**
729	>	* Initializes or doubles the capacity of array. Call either
730	>	* by owner or with lock held -- it is OK for base, but not
731	>	* top, to move while resizings are in progress.
732		*/
733	<	final boolean trySharedPush(ForkJoinTask<?> task) {
734	<	boolean submitted = false;
735	<	if (runState == 0 && U.compareAndSwapInt(this, RUNSTATE, 0, 1)) {
736	<	ForkJoinTask<?>[] a = array;
737	<	int s = top;
738	<	try {
739	<	if ((a != null && a.length > s + 1 - base) \|\|
740	<	(a = growArray(false)) != null) { // must presize
741	<	int j = (((a.length - 1) & s) << ASHIFT) + ABASE;
742	<	U.putObject(a, (long)j, task); // don't need "ordered"
743	<	top = s + 1;
744	<	submitted = true;
745	<	}
746	<	} finally {
747	<	runState = 0; // unlock
748	<	}
733	>	final ForkJoinTask<?>[] growArray() {
734	>	ForkJoinTask<?>[] oldA = array;
735	>	int size = oldA != null ? oldA.length << 1 : INITIAL_QUEUE_CAPACITY;
736	>	if (size > MAXIMUM_QUEUE_CAPACITY)
737	>	throw new RejectedExecutionException("Queue capacity exceeded");
738	>	int oldMask, t, b;
739	>	ForkJoinTask<?>[] a = array = new ForkJoinTask<?>[size];
740	>	if (oldA != null && (oldMask = oldA.length - 1) >= 0 &&
741	>	(t = top) - (b = base) > 0) {
742	>	int mask = size - 1;
743	>	do {
744	>	ForkJoinTask<?> x;
745	>	int oldj = ((b & oldMask) << ASHIFT) + ABASE;
746	>	int j = ((b & mask) << ASHIFT) + ABASE;
747	>	x = (ForkJoinTask<?>)U.getObjectVolatile(oldA, oldj);
748	>	if (x != null &&
749	>	U.compareAndSwapObject(oldA, oldj, x, null))
750	>	U.putObjectVolatile(a, j, x);
751	>	} while (++b != t);
752		}
753	<	return submitted;
753	>	return a;
754		}
755
756		/**
757		* Takes next task, if one exists, in LIFO order. Call only
758	<	* by owner in unshared queues. (We do not have a shared
721	<	* version of this method because it is never needed.)
758	>	* by owner in unshared queues.
759		*/
760		final ForkJoinTask<?> pop() {
761		ForkJoinTask<?>[] a; ForkJoinTask<?> t; int m;
#	Line 773 \| Line 810 \| public class ForkJoinPool extends Abstra
810		else if (base == b) {
811		if (b + 1 == top)
812		break;
813	<	Thread.yield(); // wait for lagging update
813	>	Thread.yield(); // wait for lagging update (very rare)
814		}
815		}
816		return null;
#	Line 800 \| Line 837 \| public class ForkJoinPool extends Abstra
837
838		/**
839		* Pops the given task only if it is at the current top.
840	+	* (A shared version is available only via FJP.tryExternalUnpush)
841		*/
842		final boolean tryUnpush(ForkJoinTask<?> t) {
843		ForkJoinTask<?>[] a; int s;
#	Line 813 \| Line 851 \| public class ForkJoinPool extends Abstra
851		}
852
853		/**
816	–	* Version of tryUnpush for shared queues; called by non-FJ
817	–	* submitters. Conservatively fails to unpush if all workers
818	–	* are active unless there are multiple tasks in queue.
819	–	*/
820	–	final boolean trySharedUnpush(ForkJoinTask<?> task, ForkJoinPool p) {
821	–	boolean success = false;
822	–	if (task != null && top != base && runState == 0 &&
823	–	U.compareAndSwapInt(this, RUNSTATE, 0, 1)) {
824	–	try {
825	–	ForkJoinTask<?>[] a; int n, s;
826	–	if ((a = array) != null && (n = (s = top) - base) > 0 &&
827	–	(n > 1 \|\| p == null \|\| (int)(p.ctl >> AC_SHIFT) < 0)) {
828	–	int j = (((a.length - 1) & --s) << ASHIFT) + ABASE;
829	–	if (U.getObjectVolatile(a, j) == task &&
830	–	U.compareAndSwapObject(a, j, task, null)) {
831	–	top = s;
832	–	success = true;
833	–	}
834	–	}
835	–	} finally {
836	–	runState = 0; // unlock
837	–	}
838	–	}
839	–	return success;
840	–	}
841	–
842	–	/**
843	–	* Polls the given task only if it is at the current base.
844	–	*/
845	–	final boolean pollFor(ForkJoinTask<?> task) {
846	–	ForkJoinTask<?>[] a; int b;
847	–	if ((b = base) - top < 0 && (a = array) != null) {
848	–	int j = (((a.length - 1) & b) << ASHIFT) + ABASE;
849	–	if (U.getObjectVolatile(a, j) == task && base == b &&
850	–	U.compareAndSwapObject(a, j, task, null)) {
851	–	base = b + 1;
852	–	return true;
853	–	}
854	–	}
855	–	return false;
856	–	}
857	–
858	–	/**
859	–	* Initializes or doubles the capacity of array. Call either
860	–	* by owner or with lock held -- it is OK for base, but not
861	–	* top, to move while resizings are in progress.
862	–	*
863	–	* @param rejectOnFailure if true, throw exception if capacity
864	–	* exceeded (relayed ultimately to user); else return null.
865	–	*/
866	–	final ForkJoinTask<?>[] growArray(boolean rejectOnFailure) {
867	–	ForkJoinTask<?>[] oldA = array;
868	–	int size = oldA != null ? oldA.length << 1 : INITIAL_QUEUE_CAPACITY;
869	–	if (size <= MAXIMUM_QUEUE_CAPACITY) {
870	–	int oldMask, t, b;
871	–	ForkJoinTask<?>[] a = array = new ForkJoinTask<?>[size];
872	–	if (oldA != null && (oldMask = oldA.length - 1) >= 0 &&
873	–	(t = top) - (b = base) > 0) {
874	–	int mask = size - 1;
875	–	do {
876	–	ForkJoinTask<?> x;
877	–	int oldj = ((b & oldMask) << ASHIFT) + ABASE;
878	–	int j = ((b & mask) << ASHIFT) + ABASE;
879	–	x = (ForkJoinTask<?>)U.getObjectVolatile(oldA, oldj);
880	–	if (x != null &&
881	–	U.compareAndSwapObject(oldA, oldj, x, null))
882	–	U.putObjectVolatile(a, j, x);
883	–	} while (++b != t);
884	–	}
885	–	return a;
886	–	}
887	–	else if (!rejectOnFailure)
888	–	return null;
889	–	else
890	–	throw new RejectedExecutionException("Queue capacity exceeded");
891	–	}
892	–
893	–	/**
854		* Removes and cancels all known tasks, ignoring any exceptions.
855		*/
856		final void cancelAll() {
#	Line 914 \| Line 874 \| public class ForkJoinPool extends Abstra
874		return seed = r ^= r << 5;
875		}
876
877	<	// Execution methods
877	>	// Specialized execution methods
878
879		/**
880		* Pops and runs tasks until empty.
#	Line 943 \| Line 903 \| public class ForkJoinPool extends Abstra
903		}
904
905		/**
906	<	* If present, removes from queue and executes the given task, or
907	<	* any other cancelled task. Returns (true) immediately on any CAS
906	>	* If present, removes from queue and executes the given task,
907	>	* or any other cancelled task. Returns (true) on any CAS
908		* or consistency check failure so caller can retry.
909		*
910	<	* @return 0 if no progress can be made, else positive
951	<	* (this unusual convention simplifies use with tryHelpStealer.)
910	>	* @return false if no progress can be made, else true;
911		*/
912	<	final int tryRemoveAndExec(ForkJoinTask<?> task) {
913	<	int stat = 1;
955	<	boolean removed = false, empty = true;
912	>	final boolean tryRemoveAndExec(ForkJoinTask<?> task) {
913	>	boolean stat = true, removed = false, empty = true;
914		ForkJoinTask<?>[] a; int m, s, b, n;
915		if ((a = array) != null && (m = a.length - 1) >= 0 &&
916		(n = (s = top) - (b = base)) > 0) {
#	Line 982 \| Line 940 \| public class ForkJoinPool extends Abstra
940		}
941		if (--n == 0) {
942		if (!empty && base == b)
943	<	stat = 0;
943	>	stat = false;
944		break;
945		}
946		}
#	Line 993 \| Line 951 \| public class ForkJoinPool extends Abstra
951		}
952
953		/**
954	+	* Polls for and executes the given task or any other task in
955	+	* its CountedCompleter computation
956	+	*/
957	+	final boolean pollAndExecCC(ForkJoinTask<?> root) {
958	+	ForkJoinTask<?>[] a; int b; Object o;
959	+	outer: while ((b = base) - top < 0 && (a = array) != null) {
960	+	long j = (((a.length - 1) & b) << ASHIFT) + ABASE;
961	+	if ((o = U.getObject(a, j)) == null \|\|
962	+	!(o instanceof CountedCompleter))
963	+	break;
964	+	for (CountedCompleter<?> t = (CountedCompleter<?>)o, r = t;;) {
965	+	if (r == root) {
966	+	if (base == b &&
967	+	U.compareAndSwapObject(a, j, t, null)) {
968	+	base = b + 1;
969	+	t.doExec();
970	+	return true;
971	+	}
972	+	else
973	+	break; // restart
974	+	}
975	+	if ((r = r.completer) == null)
976	+	break outer; // not part of root computation
977	+	}
978	+	}
979	+	return false;
980	+	}
981	+
982	+	/**
983		* Executes a top-level task and any local tasks remaining
984		* after execution.
985		*/
986		final void runTask(ForkJoinTask<?> t) {
987		if (t != null) {
988	<	currentSteal = t;
989	<	t.doExec();
990	<	if (top != base) { // process remaining local tasks
988	>	(currentSteal = t).doExec();
989	>	currentSteal = null;
990	>	++nsteals;
991	>	if (base - top < 0) { // process remaining local tasks
992		if (mode == 0)
993		popAndExecAll();
994		else
995		pollAndExecAll();
996		}
1009	–	++nsteals;
1010	–	currentSteal = null;
997		}
998		}
999
#	Line 1017 \| Line 1003 \| public class ForkJoinPool extends Abstra
1003		final void runSubtask(ForkJoinTask<?> t) {
1004		if (t != null) {
1005		ForkJoinTask<?> ps = currentSteal;
1006	<	currentSteal = t;
1021	<	t.doExec();
1006	>	(currentSteal = t).doExec();
1007		currentSteal = ps;
1008		}
1009		}
#	Line 1035 \| Line 1020 \| public class ForkJoinPool extends Abstra
1020		s != Thread.State.TIMED_WAITING);
1021		}
1022
1038	–	/**
1039	–	* If this owned and is not already interrupted, try to
1040	–	* interrupt and/or unpark, ignoring exceptions.
1041	–	*/
1042	–	final void interruptOwner() {
1043	–	Thread wt, p;
1044	–	if ((wt = owner) != null && !wt.isInterrupted()) {
1045	–	try {
1046	–	wt.interrupt();
1047	–	} catch (SecurityException ignore) {
1048	–	}
1049	–	}
1050	–	if ((p = parker) != null)
1051	–	U.unpark(p);
1052	–	}
1053	–
1023		// Unsafe mechanics
1024		private static final sun.misc.Unsafe U;
1025	<	private static final long RUNSTATE;
1025	>	private static final long QLOCK;
1026		private static final int ABASE;
1027		private static final int ASHIFT;
1028		static {
#	Line 1062 \| Line 1031 \| public class ForkJoinPool extends Abstra
1031		U = getUnsafe();
1032		Class<?> k = WorkQueue.class;
1033		Class<?> ak = ForkJoinTask[].class;
1034	<	RUNSTATE = U.objectFieldOffset
1035	<	(k.getDeclaredField("runState"));
1034	>	QLOCK = U.objectFieldOffset
1035	>	(k.getDeclaredField("qlock"));
1036		ABASE = U.arrayBaseOffset(ak);
1037		s = U.arrayIndexScale(ak);
1038		} catch (Exception e) {
#	Line 1075 \| Line 1044 \| public class ForkJoinPool extends Abstra
1044		}
1045		}
1046
1078	–	/**
1079	–	* Per-thread records for threads that submit to pools. Currently
1080	–	* holds only pseudo-random seed / index that is used to choose
1081	–	* submission queues in method doSubmit. In the future, this may
1082	–	* also incorporate a means to implement different task rejection
1083	–	* and resubmission policies.
1084	–	*
1085	–	* Seeds for submitters and workers/workQueues work in basically
1086	–	* the same way but are initialized and updated using slightly
1087	–	* different mechanics. Both are initialized using the same
1088	–	* approach as in class ThreadLocal, where successive values are
1089	–	* unlikely to collide with previous values. This is done during
1090	–	* registration for workers, but requires a separate AtomicInteger
1091	–	* for submitters. Seeds are then randomly modified upon
1092	–	* collisions using xorshifts, which requires a non-zero seed.
1093	–	*/
1094	–	static final class Submitter {
1095	–	int seed;
1096	–	Submitter() {
1097	–	int s = nextSubmitterSeed.getAndAdd(SEED_INCREMENT);
1098	–	seed = (s == 0) ? 1 : s; // ensure non-zero
1099	–	}
1100	–	}
1101	–
1102	–	/** ThreadLocal class for Submitters */
1103	–	static final class ThreadSubmitter extends ThreadLocal<Submitter> {
1104	–	public Submitter initialValue() { return new Submitter(); }
1105	–	}
1106	–
1047		// static fields (initialized in static initializer below)
1048
1049		/**
#	Line 1114 \| Line 1054 \| public class ForkJoinPool extends Abstra
1054		defaultForkJoinWorkerThreadFactory;
1055
1056		/**
1057	<	* Generator for assigning sequence numbers as pool names.
1058	<	*/
1059	<	private static final AtomicInteger poolNumberGenerator;
1060	<
1061	<	/**
1122	<	* Generator for initial hashes/seeds for submitters. Accessed by
1123	<	* Submitter class constructor.
1057	>	* Per-thread submission bookkeeping. Shared across all pools
1058	>	* to reduce ThreadLocal pollution and because random motion
1059	>	* to avoid contention in one pool is likely to hold for others.
1060	>	* Lazily initialized on first submission (but null-checked
1061	>	* in other contexts to avoid unnecessary initialization).
1062		*/
1063	<	static final AtomicInteger nextSubmitterSeed;
1063	>	static final ThreadLocal<Submitter> submitters;
1064
1065		/**
1066		* Permission required for callers of methods that may start or
#	Line 1131 \| Line 1069 \| public class ForkJoinPool extends Abstra
1069		private static final RuntimePermission modifyThreadPermission;
1070
1071		/**
1072	<	* Per-thread submission bookkeeping. Shared across all pools
1073	<	* to reduce ThreadLocal pollution and because random motion
1074	<	* to avoid contention in one pool is likely to hold for others.
1072	>	* Common (static) pool. Non-null for public use unless a static
1073	>	* construction exception, but internal usages null-check on use
1074	>	* to paranoically avoid potential initialization circularities
1075	>	* as well as to simplify generated code.
1076		*/
1077	<	private static final ThreadSubmitter submitters;
1077	>	static final ForkJoinPool common;
1078
1079	<	/** Common default pool */
1080	<	static volatile ForkJoinPool commonPool;
1079	>	/**
1080	>	* Common pool parallelism. Must equal common.parallelism.
1081	>	*/
1082	>	static final int commonParallelism;
1083
1084	<	// commonPool construction parameters
1085	<	private static final String propPrefix =
1086	<	"java.util.concurrent.ForkJoinPool.common.";
1087	<	private static final Thread.UncaughtExceptionHandler commonPoolUEH;
1147	<	private static final ForkJoinWorkerThreadFactory commonPoolFactory;
1148	<	static final int commonPoolParallelism;
1084	>	/**
1085	>	* Sequence number for creating workerNamePrefix.
1086	>	*/
1087	>	private static int poolNumberSequence;
1088
1089	<	/** Static initialization lock */
1090	<	private static final Mutex initializationLock;
1089	>	/**
1090	>	* Returns the next sequence number. We don't expect this to
1091	>	* ever contend, so use simple builtin sync.
1092	>	*/
1093	>	private static final synchronized int nextPoolId() {
1094	>	return ++poolNumberSequence;
1095	>	}
1096
1097		// static constants
1098
1099		/**
1100	<	* Initial timeout value (in nanoseconds) for the tread triggering
1101	<	* quiescence to park waiting for new work. On timeout, the thread
1102	<	* will instead try to shrink the number of workers.
1100	>	* Initial timeout value (in nanoseconds) for the thread
1101	>	* triggering quiescence to park waiting for new work. On timeout,
1102	>	* the thread will instead try to shrink the number of
1103	>	* workers. The value should be large enough to avoid overly
1104	>	* aggressive shrinkage during most transient stalls (long GCs
1105	>	* etc).
1106		*/
1107	<	private static final long IDLE_TIMEOUT = 1000L * 1000L * 1000L; // 1sec
1107	>	private static final long IDLE_TIMEOUT = 2000L * 1000L * 1000L; // 2sec
1108
1109		/**
1110		* Timeout value when there are more threads than parallelism level
1111		*/
1112	<	private static final long FAST_IDLE_TIMEOUT = 100L * 1000L * 1000L;
1112	>	private static final long FAST_IDLE_TIMEOUT = 200L * 1000L * 1000L;
1113	>
1114	>	/**
1115	>	* Tolerance for idle timeouts, to cope with timer undershoots
1116	>	*/
1117	>	private static final long TIMEOUT_SLOP = 2000000L;
1118
1119		/**
1120		* The maximum stolen->joining link depth allowed in method
1121	<	* tryHelpStealer. Must be a power of two. This value also
1170	<	* controls the maximum number of times to try to help join a task
1171	<	* without any apparent progress or change in pool state before
1172	<	* giving up and blocking (see awaitJoin). Depths for legitimate
1121	>	* tryHelpStealer. Must be a power of two. Depths for legitimate
1122		* chains are unbounded, but we use a fixed constant to avoid
1123		* (otherwise unchecked) cycles and to bound staleness of
1124		* traversal parameters at the expense of sometimes blocking when
#	Line 1178 \| Line 1127 \| public class ForkJoinPool extends Abstra
1127		private static final int MAX_HELP = 64;
1128
1129		/**
1181	–	* Secondary time-based bound (in nanosecs) for helping attempts
1182	–	* before trying compensated blocking in awaitJoin. Used in
1183	–	* conjunction with MAX_HELP to reduce variance due to different
1184	–	* polling rates associated with different helping options. The
1185	–	* value should roughly approximate the time required to create
1186	–	* and/or activate a worker thread.
1187	–	*/
1188	–	private static final long COMPENSATION_DELAY = 1L << 18; // ~0.25 millisec
1189	–
1190	–	/**
1130		* Increment for seed generators. See class ThreadLocal for
1131		* explanation.
1132		*/
#	Line 1221 \| Line 1160 \| public class ForkJoinPool extends Abstra
1160		* scan for them to avoid queuing races. Note however that
1161		* eventCount updates lag releases so usage requires care.
1162		*
1163	<	* Field runState is an int packed with:
1163	>	* Field plock is an int packed with:
1164		* SHUTDOWN: true if shutdown is enabled (1 bit)
1165	<	* SEQ: a sequence number updated upon (de)registering workers (30 bits)
1166	<	* INIT: set true after workQueues array construction (1 bit)
1165	>	* SEQ: a sequence lock, with PL_LOCK bit set if locked (30 bits)
1166	>	* SIGNAL: set when threads may be waiting on the lock (1 bit)
1167		*
1168		* The sequence number enables simple consistency checks:
1169		* Staleness of read-only operations on the workQueues array can
1170	<	* be checked by comparing runState before vs after the reads.
1170	>	* be checked by comparing plock before vs after the reads.
1171		*/
1172
1173		// bit positions/shifts for fields
#	Line 1240 \| Line 1179 \| public class ForkJoinPool extends Abstra
1179		// bounds
1180		private static final int SMASK = 0xffff; // short bits
1181		private static final int MAX_CAP = 0x7fff; // max #workers - 1
1182	<	private static final int SQMASK = 0xfffe; // even short bits
1182	>	private static final int EVENMASK = 0xfffe; // even short bits
1183	>	private static final int SQMASK = 0x007e; // max 64 (even) slots
1184		private static final int SHORT_SIGN = 1 << 15;
1185		private static final int INT_SIGN = 1 << 31;
1186
#	Line 1265 \| Line 1205 \| public class ForkJoinPool extends Abstra
1205		private static final int E_MASK = 0x7fffffff; // no STOP_BIT
1206		private static final int E_SEQ = 1 << EC_SHIFT;
1207
1208	<	// runState bits
1208	>	// plock bits
1209		private static final int SHUTDOWN = 1 << 31;
1210	+	private static final int PL_LOCK = 2;
1211	+	private static final int PL_SIGNAL = 1;
1212	+	private static final int PL_SPINS = 1 << 8;
1213
1214		// access mode for WorkQueue
1215		static final int LIFO_QUEUE = 0;
1216		static final int FIFO_QUEUE = 1;
1217		static final int SHARED_QUEUE = -1;
1218
1219	+	// bounds for #steps in scan loop -- must be power 2 minus 1
1220	+	private static final int MIN_SCAN = 0x1ff; // cover estimation slop
1221	+	private static final int MAX_SCAN = 0x1ffff; // 4 * max workers
1222	+
1223		// Instance fields
1224
1225		/*
1226	<	* Field layout order in this class tends to matter more than one
1227	<	* would like. Runtime layout order is only loosely related to
1226	>	* Field layout of this class tends to matter more than one would
1227	>	* like. Runtime layout order is only loosely related to
1228		* declaration order and may differ across JVMs, but the following
1229		* empirically works OK on current JVMs.
1230		*/
1231
1232	+	// Heuristic padding to ameliorate unfortunate memory placements
1233	+	volatile long pad00, pad01, pad02, pad03, pad04, pad05, pad06;
1234	+
1235	+	volatile long stealCount; // collects worker counts
1236		volatile long ctl; // main pool control
1237	<	final int parallelism; // parallelism level
1238	<	final int localMode; // per-worker scheduling mode
1239	<	final int submitMask; // submit queue index bound
1289	<	int nextSeed; // for initializing worker seeds
1290	<	volatile int runState; // shutdown status and seq
1237	>	volatile int plock; // shutdown status and seqLock
1238	>	volatile int indexSeed; // worker/submitter index seed
1239	>	final int config; // mode and parallelism level
1240		WorkQueue[] workQueues; // main registry
1241	<	final Mutex lock; // for registration
1293	<	final Condition termination; // for awaitTermination
1294	<	final ForkJoinWorkerThreadFactory factory; // factory for new workers
1241	>	final ForkJoinWorkerThreadFactory factory;
1242		final Thread.UncaughtExceptionHandler ueh; // per-worker UEH
1243	<	final AtomicLong stealCount; // collect counts when terminated
1297	<	final AtomicInteger nextWorkerNumber; // to create worker name string
1298	<	String workerNamePrefix; // to create worker name string
1243	>	final String workerNamePrefix; // to create worker name string
1244
1245	<	// Creating, registering, and deregistering workers
1245	>	volatile Object pad10, pad11, pad12, pad13, pad14, pad15, pad16, pad17;
1246	>	volatile Object pad18, pad19, pad1a, pad1b;
1247
1248	<	/**
1249	<	* Tries to create and start a worker
1250	<	*/
1251	<	private void addWorker() {
1252	<	Throwable ex = null;
1253	<	ForkJoinWorkerThread wt = null;
1254	<	try {
1255	<	if ((wt = factory.newThread(this)) != null) {
1256	<	wt.start();
1257	<	return;
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
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.
1255	>	*/
1256	>	private int acquirePlock() {
1257	>	int spins = PL_SPINS, r = 0, ps, nps;
1258	>	for (;;) {
1259	>	if (((ps = plock) & PL_LOCK) == 0 &&
1260	>	U.compareAndSwapInt(this, PLOCK, ps, nps = ps + PL_LOCK))
1261	>	return nps;
1262	>	else if (r == 0) { // randomize spins if possible
1263	>	Thread t = Thread.currentThread(); WorkQueue w; Submitter z;
1264	>	if ((t instanceof ForkJoinWorkerThread) &&
1265	>	(w = ((ForkJoinWorkerThread)t).workQueue) != null)
1266	>	r = w.seed;
1267	>	else if ((z = submitters.get()) != null)
1268	>	r = z.seed;
1269	>	else
1270	>	r = 1;
1271	>	}
1272	>	else if (spins >= 0) {
1273	>	r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
1274	>	if (r >= 0)
1275	>	--spins;
1276	>	}
1277	>	else if (U.compareAndSwapInt(this, PLOCK, ps, ps \| PL_SIGNAL)) {
1278	>	synchronized (this) {
1279	>	if ((plock & PL_SIGNAL) != 0) {
1280	>	try {
1281	>	wait();
1282	>	} catch (InterruptedException ie) {
1283	>	try {
1284	>	Thread.currentThread().interrupt();
1285	>	} catch (SecurityException ignore) {
1286	>	}
1287	>	}
1288	>	}
1289	>	else
1290	>	notifyAll();
1291	>	}
1292		}
1313	–	} catch (Throwable e) {
1314	–	ex = e;
1293		}
1316	–	deregisterWorker(wt, ex); // adjust counts etc on failure
1294		}
1295
1296		/**
1297	<	* Callback from ForkJoinWorkerThread constructor to assign a
1298	<	* public name. This must be separate from registerWorker because
1322	<	* it is called during the "super" constructor call in
1323	<	* ForkJoinWorkerThread.
1297	>	* Unlocks and signals any thread waiting for plock. Called only
1298	>	* when CAS of seq value for unlock fails.
1299		*/
1300	<	final String nextWorkerName() {
1301	<	return workerNamePrefix.concat
1302	<	(Integer.toString(nextWorkerNumber.addAndGet(1)));
1300	>	private void releasePlock(int ps) {
1301	>	plock = ps;
1302	>	synchronized (this) { notifyAll(); }
1303		}
1304
1305		/**
1306	<	* Callback from ForkJoinWorkerThread constructor to establish its
1307	<	* poolIndex and record its WorkQueue. To avoid scanning bias due
1333	<	* to packing entries in front of the workQueues array, we treat
1334	<	* the array as a simple power-of-two hash table using per-thread
1335	<	* seed as hash, expanding as needed.
1336	<	*
1337	<	* @param w the worker's queue
1306	>	* Tries to create and start one worker if fewer than target
1307	>	* parallelism level exist. Adjusts counts etc on failure.
1308		*/
1309	<	final void registerWorker(WorkQueue w) {
1310	<	Mutex lock = this.lock;
1311	<	lock.lock();
1309	>	private void tryAddWorker() {
1310	>	long c; int u;
1311	>	while ((u = (int)((c = ctl) >>> 32)) < 0 &&
1312	>	(u & SHORT_SIGN) != 0 && (int)c == 0) {
1313	>	long nc = (long)(((u + UTC_UNIT) & UTC_MASK) \|
1314	>	((u + UAC_UNIT) & UAC_MASK)) << 32;
1315	>	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1316	>	ForkJoinWorkerThreadFactory fac;
1317	>	Throwable ex = null;
1318	>	ForkJoinWorkerThread wt = null;
1319	>	try {
1320	>	if ((fac = factory) != null &&
1321	>	(wt = fac.newThread(this)) != null) {
1322	>	wt.start();
1323	>	break;
1324	>	}
1325	>	} catch (Throwable e) {
1326	>	ex = e;
1327	>	}
1328	>	deregisterWorker(wt, ex);
1329	>	break;
1330	>	}
1331	>	}
1332	>	}
1333	>
1334	>	// Registering and deregistering workers
1335	>
1336	>	/**
1337	>	* Callback from ForkJoinWorkerThread to establish and record its
1338	>	* WorkQueue. To avoid scanning bias due to packing entries in
1339	>	* front of the workQueues array, we treat the array as a simple
1340	>	* power-of-two hash table using per-thread seed as hash,
1341	>	* expanding as needed.
1342	>	*
1343	>	* @param wt the worker thread
1344	>	* @return the worker's queue
1345	>	*/
1346	>	final WorkQueue registerWorker(ForkJoinWorkerThread wt) {
1347	>	Thread.UncaughtExceptionHandler handler; WorkQueue[] ws; int s, ps;
1348	>	wt.setDaemon(true);
1349	>	if ((handler = ueh) != null)
1350	>	wt.setUncaughtExceptionHandler(handler);
1351	>	do {} while (!U.compareAndSwapInt(this, INDEXSEED, s = indexSeed,
1352	>	s += SEED_INCREMENT) \|\|
1353	>	s == 0); // skip 0
1354	>	WorkQueue w = new WorkQueue(this, wt, config >>> 16, s);
1355	>	if (((ps = plock) & PL_LOCK) != 0 \|\|
1356	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1357	>	ps = acquirePlock();
1358	>	int nps = (ps & SHUTDOWN) \| ((ps + PL_LOCK) & ~SHUTDOWN);
1359		try {
1360	<	WorkQueue[] ws = workQueues;
1361	<	if (w != null && ws != null) { // skip on shutdown/failure
1362	<	int rs, n = ws.length, m = n - 1;
1363	<	int s = nextSeed += SEED_INCREMENT; // rarely-colliding sequence
1364	<	w.seed = (s == 0) ? 1 : s; // ensure non-zero seed
1365	<	int r = (s << 1) \| 1; // use odd-numbered indices
1349	<	if (ws[r &= m] != null) { // collision
1350	<	int probes = 0; // step by approx half size
1351	<	int step = (n <= 4) ? 2 : ((n >>> 1) & SQMASK) + 2;
1360	>	if ((ws = workQueues) != null) { // skip if shutting down
1361	>	int n = ws.length, m = n - 1;
1362	>	int r = (s << 1) \| 1; // use odd-numbered indices
1363	>	if (ws[r &= m] != null) { // collision
1364	>	int probes = 0; // step by approx half size
1365	>	int step = (n <= 4) ? 2 : ((n >>> 1) & EVENMASK) + 2;
1366		while (ws[r = (r + step) & m] != null) {
1367		if (++probes >= n) {
1368		workQueues = ws = Arrays.copyOf(ws, n <<= 1);
#	Line 1357 \| Line 1371 \| public class ForkJoinPool extends Abstra
1371		}
1372		}
1373		}
1374	<	w.eventCount = w.poolIndex = r; // establish before recording
1375	<	ws[r] = w; // also update seq
1362	<	runState = ((rs = runState) & SHUTDOWN) \| ((rs + 2) & ~SHUTDOWN);
1374	>	w.eventCount = w.poolIndex = r; // volatile write orders
1375	>	ws[r] = w;
1376		}
1377		} finally {
1378	<	lock.unlock();
1378	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1379	>	releasePlock(nps);
1380		}
1381	+	wt.setName(workerNamePrefix.concat(Integer.toString(w.poolIndex)));
1382	+	return w;
1383		}
1384
1385		/**
1386		* Final callback from terminating worker, as well as upon failure
1387	<	* to construct or start a worker in addWorker. Removes record of
1388	<	* worker from array, and adjusts counts. If pool is shutting
1389	<	* down, tries to complete termination.
1387	>	* to construct or start a worker. Removes record of worker from
1388	>	* array, and adjusts counts. If pool is shutting down, tries to
1389	>	* complete termination.
1390		*
1391	<	* @param wt the worker thread or null if addWorker failed
1391	>	* @param wt the worker thread or null if construction failed
1392		* @param ex the exception causing failure, or null if none
1393		*/
1394		final void deregisterWorker(ForkJoinWorkerThread wt, Throwable ex) {
1379	–	Mutex lock = this.lock;
1395		WorkQueue w = null;
1396		if (wt != null && (w = wt.workQueue) != null) {
1397	<	w.runState = -1; // ensure runState is set
1398	<	stealCount.getAndAdd(w.totalSteals + w.nsteals);
1399	<	int idx = w.poolIndex;
1400	<	lock.lock();
1401	<	try { // remove record from array
1397	>	int ps;
1398	>	w.qlock = -1; // ensure set
1399	>	long ns = w.nsteals, sc; // collect steal count
1400	>	do {} while (!U.compareAndSwapLong(this, STEALCOUNT,
1401	>	sc = stealCount, sc + ns));
1402	>	if (((ps = plock) & PL_LOCK) != 0 \|\|
1403	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1404	>	ps = acquirePlock();
1405	>	int nps = (ps & SHUTDOWN) \| ((ps + PL_LOCK) & ~SHUTDOWN);
1406	>	try {
1407	>	int idx = w.poolIndex;
1408		WorkQueue[] ws = workQueues;
1409		if (ws != null && idx >= 0 && idx < ws.length && ws[idx] == w)
1410		ws[idx] = null;
1411		} finally {
1412	<	lock.unlock();
1412	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1413	>	releasePlock(nps);
1414		}
1415		}
1416
1417	<	long c; // adjust ctl counts
1417	>	long c; // adjust ctl counts
1418		do {} while (!U.compareAndSwapLong
1419		(this, CTL, c = ctl, (((c - AC_UNIT) & AC_MASK) \|
1420		((c - TC_UNIT) & TC_MASK) \|
1421		(c & ~(AC_MASK\|TC_MASK)))));
1422
1423	<	if (!tryTerminate(false, false) && w != null) {
1424	<	w.cancelAll(); // cancel remaining tasks
1425	<	if (w.array != null) // suppress signal if never ran
1426	<	signalWork(); // wake up or create replacement
1427	<	if (ex == null) // help clean refs on way out
1428	<	ForkJoinTask.helpExpungeStaleExceptions();
1423	>	if (!tryTerminate(false, false) && w != null && w.array != null) {
1424	>	w.cancelAll(); // cancel remaining tasks
1425	>	WorkQueue[] ws; WorkQueue v; Thread p; int u, i, e;
1426	>	while ((u = (int)((c = ctl) >>> 32)) < 0 && (e = (int)c) >= 0) {
1427	>	if (e > 0) { // activate or create replacement
1428	>	if ((ws = workQueues) == null \|\|
1429	>	(i = e & SMASK) >= ws.length \|\|
1430	>	(v = ws[i]) == null)
1431	>	break;
1432	>	long nc = (((long)(v.nextWait & E_MASK)) \|
1433	>	((long)(u + UAC_UNIT) << 32));
1434	>	if (v.eventCount != (e \| INT_SIGN))
1435	>	break;
1436	>	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1437	>	v.eventCount = (e + E_SEQ) & E_MASK;
1438	>	if ((p = v.parker) != null)
1439	>	U.unpark(p);
1440	>	break;
1441	>	}
1442	>	}
1443	>	else {
1444	>	if ((short)u < 0)
1445	>	tryAddWorker();
1446	>	break;
1447	>	}
1448	>	}
1449		}
1450	<
1451	<	if (ex != null) // rethrow
1452	<	U.throwException(ex);
1450	>	if (ex == null) // help clean refs on way out
1451	>	ForkJoinTask.helpExpungeStaleExceptions();
1452	>	else // rethrow
1453	>	ForkJoinTask.rethrow(ex);
1454		}
1455
1456		// Submissions
#	Line 1415 \| Line 1458 \| public class ForkJoinPool extends Abstra
1458		/**
1459		* Unless shutting down, adds the given task to a submission queue
1460		* at submitter's current queue index (modulo submission
1461	<	* range). If no queue exists at the index, one is created. If
1462	<	* the queue is busy, another index is randomly chosen. The
1420	<	* submitMask bounds the effective number of queues to the
1421	<	* (nearest power of two for) parallelism level.
1461	>	* range). Only the most common path is directly handled in this
1462	>	* method. All others are relayed to fullExternalPush.
1463		*
1464		* @param task the task. Caller must ensure non-null.
1465		*/
1466	<	private void doSubmit(ForkJoinTask<?> task) {
1467	<	Submitter s = submitters.get();
1468	<	for (int r = s.seed, m = submitMask;;) {
1469	<	WorkQueue[] ws; WorkQueue q;
1470	<	int k = r & m & SQMASK; // use only even indices
1471	<	if (runState < 0 \|\| (ws = workQueues) == null \|\| ws.length <= k)
1472	<	throw new RejectedExecutionException(); // shutting down
1473	<	else if ((q = ws[k]) == null) { // create new queue
1474	<	WorkQueue nq = new WorkQueue(this, null, SHARED_QUEUE);
1475	<	Mutex lock = this.lock; // construct outside lock
1476	<	lock.lock();
1477	<	try { // recheck under lock
1478	<	int rs = runState; // to update seq
1479	<	if (ws == workQueues && ws[k] == null) {
1439	<	ws[k] = nq;
1440	<	runState = ((rs & SHUTDOWN) \| ((rs + 2) & ~SHUTDOWN));
1441	<	}
1442	<	} finally {
1443	<	lock.unlock();
1444	<	}
1445	<	}
1446	<	else if (q.trySharedPush(task)) {
1447	<	signalWork();
1466	>	final void externalPush(ForkJoinTask<?> task) {
1467	>	WorkQueue[] ws; WorkQueue q; Submitter z; int m; ForkJoinTask<?>[] a;
1468	>	if ((z = submitters.get()) != null && plock > 0 &&
1469	>	(ws = workQueues) != null && (m = (ws.length - 1)) >= 0 &&
1470	>	(q = ws[m & z.seed & SQMASK]) != null &&
1471	>	U.compareAndSwapInt(q, QLOCK, 0, 1)) { // lock
1472	>	int b = q.base, s = q.top, n, an;
1473	>	if ((a = q.array) != null && (an = a.length) > (n = s + 1 - b)) {
1474	>	int j = (((an - 1) & s) << ASHIFT) + ABASE;
1475	>	U.putOrderedObject(a, j, task);
1476	>	q.top = s + 1; // push on to deque
1477	>	q.qlock = 0;
1478	>	if (n <= 2)
1479	>	signalWork(q);
1480		return;
1481		}
1482	<	else if (m > 1) { // move to a different index
1451	<	r ^= r << 13; // same xorshift as WorkQueues
1452	<	r ^= r >>> 17;
1453	<	s.seed = r ^= r << 5;
1454	<	}
1455	<	else
1456	<	Thread.yield(); // yield if no alternatives
1482	>	q.qlock = 0;
1483		}
1484	+	fullExternalPush(task);
1485		}
1486
1487		/**
1488	<	* Submits the given (non-null) task to the common pool, if possible.
1489	<	*/
1490	<	static void submitToCommonPool(ForkJoinTask<?> task) {
1491	<	ForkJoinPool p;
1492	<	if ((p = commonPool) == null)
1493	<	p = ensureCommonPool();
1494	<	p.doSubmit(task);
1495	<	}
1496	<
1497	<	/**
1498	<	* Returns true if the given task was submitted to common pool
1499	<	* and has not yet commenced execution, and is available for
1500	<	* removal according to execution policies; if so removing the
1501	<	* submission from the pool.
1502	<	*
1503	<	* @param task the task
1504	<	* @return true if successful
1505	<	*/
1506	<	static boolean tryUnsubmitFromCommonPool(ForkJoinTask<?> task) {
1507	<	ForkJoinPool p; WorkQueue[] ws; WorkQueue q;
1508	<	int k = submitters.get().seed & SQMASK;
1509	<	return ((p = commonPool) != null &&
1510	<	(ws = p.workQueues) != null &&
1511	<	ws.length > (k &= p.submitMask) &&
1512	<	(q = ws[k]) != null &&
1513	<	q.trySharedUnpush(task, p));
1488	>	* Full version of externalPush. This method is called, among
1489	>	* other times, upon the first submission of the first task to the
1490	>	* pool, so must perform secondary initialization. It also
1491	>	* detects first submission by an external thread by looking up
1492	>	* its ThreadLocal, and creates a new shared queue if the one at
1493	>	* index if empty or contended. The plock lock body must be
1494	>	* exception-free (so no try/finally) so we optimistically
1495	>	* allocate new queues outside the lock and throw them away if
1496	>	* (very rarely) not needed.
1497	>	*
1498	>	* Secondary initialization occurs when plock is zero, to create
1499	>	* workQueue array and set plock to a valid value. This lock body
1500	>	* must also be exception-free. Because the plock seq value can
1501	>	* eventually wrap around zero, this method harmlessly fails to
1502	>	* reinitialize if workQueues exists, while still advancing plock.
1503	>	*/
1504	>	private void fullExternalPush(ForkJoinTask<?> task) {
1505	>	int r = 0; // random index seed
1506	>	for (Submitter z = submitters.get();;) {
1507	>	WorkQueue[] ws; WorkQueue q; int ps, m, k;
1508	>	if (z == null) {
1509	>	if (U.compareAndSwapInt(this, INDEXSEED, r = indexSeed,
1510	>	r += SEED_INCREMENT) && r != 0)
1511	>	submitters.set(z = new Submitter(r));
1512	>	}
1513	>	else if (r == 0) { // move to a different index
1514	>	r = z.seed;
1515	>	r ^= r << 13; // same xorshift as WorkQueues
1516	>	r ^= r >>> 17;
1517	>	z.seed = r ^ (r << 5);
1518	>	}
1519	>	else if ((ps = plock) < 0)
1520	>	throw new RejectedExecutionException();
1521	>	else if (ps == 0 \|\| (ws = workQueues) == null \|\|
1522	>	(m = ws.length - 1) < 0) { // initialize workQueues
1523	>	int p = config & SMASK; // find power of two table size
1524	>	int n = (p > 1) ? p - 1 : 1; // ensure at least 2 slots
1525	>	n \|= n >>> 1; n \|= n >>> 2; n \|= n >>> 4;
1526	>	n \|= n >>> 8; n \|= n >>> 16; n = (n + 1) << 1;
1527	>	WorkQueue[] nws = ((ws = workQueues) == null \|\| ws.length == 0 ?
1528	>	new WorkQueue[n] : null);
1529	>	if (((ps = plock) & PL_LOCK) != 0 \|\|
1530	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1531	>	ps = acquirePlock();
1532	>	if (((ws = workQueues) == null \|\| ws.length == 0) && nws != null)
1533	>	workQueues = nws;
1534	>	int nps = (ps & SHUTDOWN) \| ((ps + PL_LOCK) & ~SHUTDOWN);
1535	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1536	>	releasePlock(nps);
1537	>	}
1538	>	else if ((q = ws[k = r & m & SQMASK]) != null) {
1539	>	if (q.qlock == 0 && U.compareAndSwapInt(q, QLOCK, 0, 1)) {
1540	>	ForkJoinTask<?>[] a = q.array;
1541	>	int s = q.top;
1542	>	boolean submitted = false;
1543	>	try { // locked version of push
1544	>	if ((a != null && a.length > s + 1 - q.base) \|\|
1545	>	(a = q.growArray()) != null) { // must presize
1546	>	int j = (((a.length - 1) & s) << ASHIFT) + ABASE;
1547	>	U.putOrderedObject(a, j, task);
1548	>	q.top = s + 1;
1549	>	submitted = true;
1550	>	}
1551	>	} finally {
1552	>	q.qlock = 0; // unlock
1553	>	}
1554	>	if (submitted) {
1555	>	signalWork(q);
1556	>	return;
1557	>	}
1558	>	}
1559	>	r = 0; // move on failure
1560	>	}
1561	>	else if (((ps = plock) & PL_LOCK) == 0) { // create new queue
1562	>	q = new WorkQueue(this, null, SHARED_QUEUE, r);
1563	>	if (((ps = plock) & PL_LOCK) != 0 \|\|
1564	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1565	>	ps = acquirePlock();
1566	>	if ((ws = workQueues) != null && k < ws.length && ws[k] == null)
1567	>	ws[k] = q;
1568	>	int nps = (ps & SHUTDOWN) \| ((ps + PL_LOCK) & ~SHUTDOWN);
1569	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1570	>	releasePlock(nps);
1571	>	}
1572	>	else
1573	>	r = 0; // try elsewhere while lock held
1574	>	}
1575		}
1576
1577		// Maintaining ctl counts
#	Line 1497 \| Line 1585 \| public class ForkJoinPool extends Abstra
1585		}
1586
1587		/**
1588	<	* Tries to create one or activate one or more workers if too few are active.
1588	>	* Tries to create or activate a worker if too few are active.
1589	>	*
1590	>	* @param q the (non-null) queue holding tasks to be signalled
1591		*/
1592	<	final void signalWork() {
1593	<	long c; int u;
1594	<	while ((u = (int)((c = ctl) >>> 32)) < 0) { // too few active
1595	<	WorkQueue[] ws = workQueues; int e, i; WorkQueue w; Thread p;
1596	<	if ((e = (int)c) > 0) { // at least one waiting
1597	<	if (ws != null && (i = e & SMASK) < ws.length &&
1592	>	final void signalWork(WorkQueue q) {
1593	>	int hint = q.poolIndex;
1594	>	long c; int e, u, i, n; WorkQueue[] ws; WorkQueue w; Thread p;
1595	>	while ((u = (int)((c = ctl) >>> 32)) < 0) {
1596	>	if ((e = (int)c) > 0) {
1597	>	if ((ws = workQueues) != null && ws.length > (i = e & SMASK) &&
1598		(w = ws[i]) != null && w.eventCount == (e \| INT_SIGN)) {
1599		long nc = (((long)(w.nextWait & E_MASK)) \|
1600		((long)(u + UAC_UNIT) << 32));
1601		if (U.compareAndSwapLong(this, CTL, c, nc)) {
1602	+	w.hint = hint;
1603		w.eventCount = (e + E_SEQ) & E_MASK;
1604		if ((p = w.parker) != null)
1605	<	U.unpark(p); // activate and release
1605	>	U.unpark(p);
1606		break;
1607		}
1608	+	if (q.top - q.base <= 0)
1609	+	break;
1610		}
1611		else
1612		break;
1613		}
1614	<	else if (e == 0 && (u & SHORT_SIGN) != 0) { // too few total
1615	<	long nc = (long)(((u + UTC_UNIT) & UTC_MASK) \|
1616	<	((u + UAC_UNIT) & UAC_MASK)) << 32;
1524	<	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1525	<	addWorker();
1526	<	break;
1527	<	}
1528	<	}
1529	<	else
1614	>	else {
1615	>	if ((short)u < 0)
1616	>	tryAddWorker();
1617		break;
1618	+	}
1619		}
1620		}
1621
#	Line 1537 \| Line 1625 \| public class ForkJoinPool extends Abstra
1625		* Top-level runloop for workers, called by ForkJoinWorkerThread.run.
1626		*/
1627		final void runWorker(WorkQueue w) {
1628	<	w.growArray(false); // initialize queue array in this thread
1629	<	do { w.runTask(scan(w)); } while (w.runState >= 0);
1628	>	w.growArray(); // allocate queue
1629	>	do { w.runTask(scan(w)); } while (w.qlock >= 0);
1630		}
1631
1632		/**
#	Line 1549 \| Line 1637 \| public class ForkJoinPool extends Abstra
1637		* contention, or state changes that indicate possible success on
1638		* re-invocation.
1639		*
1640	<	* The scan searches for tasks across a random permutation of
1641	<	* queues (starting at a random index and stepping by a random
1642	<	* relative prime, checking each at least once). The scan
1643	<	* terminates upon either finding a non-empty queue, or completing
1644	<	* the sweep. If the worker is not inactivated, it takes and
1645	<	* returns a task from this queue. On failure to find a task, we
1646	<	* take one of the following actions, after which the caller will
1647	<	* retry calling this method unless terminated.
1640	>	* The scan searches for tasks across queues (starting at a random
1641	>	* index, and relying on registerWorker to irregularly scatter
1642	>	* them within array to avoid bias), checking each at least twice.
1643	>	* The scan terminates upon either finding a non-empty queue, or
1644	>	* completing the sweep. If the worker is not inactivated, it
1645	>	* takes and returns a task from this queue. Otherwise, if not
1646	>	* activated, it signals workers (that may include itself) and
1647	>	* returns so caller can retry. Also returns for true if the
1648	>	* worker array may have changed during an empty scan. On failure
1649	>	* to find a task, we take one of the following actions, after
1650	>	* which the caller will retry calling this method unless
1651	>	* terminated.
1652		*
1653		* * If pool is terminating, terminate the worker.
1654		*
1563	–	* * If not a complete sweep, try to release a waiting worker. If
1564	–	* the scan terminated because the worker is inactivated, then the
1565	–	* released worker will often be the calling worker, and it can
1566	–	* succeed obtaining a task on the next call. Or maybe it is
1567	–	* another worker, but with same net effect. Releasing in other
1568	–	* cases as well ensures that we have enough workers running.
1569	–	*
1655		* * If not already enqueued, try to inactivate and enqueue the
1656		* worker on wait queue. Or, if inactivating has caused the pool
1657	<	* to be quiescent, relay to idleAwaitWork to check for
1658	<	* termination and possibly shrink pool.
1657	>	* to be quiescent, relay to idleAwaitWork to possibly shrink
1658	>	* pool.
1659		*
1660	<	* * If already inactive, and the caller has run a task since the
1661	<	* last empty scan, return (to allow rescan) unless others are
1577	<	* also inactivated. Field WorkQueue.rescans counts down on each
1578	<	* scan to ensure eventual inactivation and blocking.
1660	>	* * If already enqueued and none of the above apply, possibly
1661	>	* park awaiting signal, else lingering to help scan and signal.
1662		*
1663	<	* * If already enqueued and none of the above apply, park
1664	<	* awaiting signal,
1663	>	* * If a non-empty queue discovered or left as a hint,
1664	>	* help wake up other workers before return.
1665		*
1666		* @param w the worker (via its WorkQueue)
1667		* @return a task or null if none found
1668		*/
1669		private final ForkJoinTask<?> scan(WorkQueue w) {
1670	<	WorkQueue[] ws; // first update random seed
1671	<	int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
1672	<	int rs = runState, m; // volatile read order matters
1673	<	if ((ws = workQueues) != null && (m = ws.length - 1) > 0) {
1674	<	int ec = w.eventCount; // ec is negative if inactive
1675	<	int step = (r >>> 16) \| 1; // relative prime
1676	<	for (int j = (m + 1) << 2; ; r += step) {
1677	<	WorkQueue q; ForkJoinTask<?> t; ForkJoinTask<?>[] a; int b;
1678	<	if ((q = ws[r & m]) != null && (b = q.base) - q.top < 0 &&
1679	<	(a = q.array) != null) { // probably nonempty
1670	>	WorkQueue[] ws; int m;
1671	>	int ps = plock; // read plock before ws
1672	>	if (w != null && (ws = workQueues) != null && (m = ws.length - 1) >= 0) {
1673	>	int ec = w.eventCount; // ec is negative if inactive
1674	>	int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
1675	>	w.hint = -1; // update seed and clear hint
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	<	t = (ForkJoinTask<?>)U.getObjectVolatile(a, i);
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.top - (q.base = b + 1) > 0)
1687	<	signalWork(); // help pushes signal
1688	<	return t;
1689	<	}
1690	<	else if (ec < 0 \|\| j <= m) {
1691	<	rs = 0; // mark scan as imcomplete
1692	<	break; // caller can retry after release
1693	<	}
1694	<	}
1695	<	if (--j < 0)
1696	<	break;
1697	<	}
1698	<
1699	<	long c = ctl; int e = (int)c, a = (int)(c >> AC_SHIFT), nr, ns;
1700	<	if (e < 0) // decode ctl on empty scan
1701	<	w.runState = -1; // pool is terminating
1702	<	else if (rs == 0 \|\| rs != runState) { // incomplete scan
1703	<	WorkQueue v; Thread p; // try to release a waiter
1704	<	if (e > 0 && a < 0 && w.eventCount == ec &&
1705	<	(v = ws[e & m]) != null && v.eventCount == (e \| INT_SIGN)) {
1706	<	long nc = ((long)(v.nextWait & E_MASK) \|
1707	<	((c + AC_UNIT) & (AC_MASK\|TC_MASK)));
1708	<	if (ctl == c && U.compareAndSwapLong(this, CTL, c, nc)) {
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
1692	>	break; // cannot take
1693	>	}
1694	>	}
1695	>	} while (--j >= 0);
1696	>
1697	>	int h, e, ns; long c, sc; WorkQueue q;
1698	>	if ((ns = w.nsteals) != 0) {
1699	>	if (U.compareAndSwapLong(this, STEALCOUNT,
1700	>	sc = stealCount, sc + ns))
1701	>	w.nsteals = 0; // collect steals and rescan
1702	>	}
1703	>	else if (plock != ps) // consistency check
1704	>	; // skip
1705	>	else if ((e = (int)(c = ctl)) < 0)
1706	>	w.qlock = -1; // pool is terminating
1707	>	else {
1708	>	if ((h = w.hint) < 0) {
1709	>	if (ec >= 0) { // try to enqueue/inactivate
1710	>	long nc = (((long)ec \|
1711	>	((c - AC_UNIT) & (AC_MASK\|TC_MASK))));
1712	>	w.nextWait = e; // link and mark inactive
1713	>	w.eventCount = ec \| INT_SIGN;
1714	>	if (ctl != c \|\| !U.compareAndSwapLong(this, CTL, c, nc))
1715	>	w.eventCount = ec; // unmark on CAS failure
1716	>	else if ((int)(c >> AC_SHIFT) == 1 - (config & SMASK))
1717	>	idleAwaitWork(w, nc, c);
1718	>	}
1719	>	else if (w.eventCount < 0 && ctl == c) {
1720	>	Thread wt = Thread.currentThread();
1721	>	Thread.interrupted(); // clear status
1722	>	U.putObject(wt, PARKBLOCKER, this);
1723	>	w.parker = wt; // emulate LockSupport.park
1724	>	if (w.eventCount < 0) // recheck
1725	>	U.park(false, 0L); // block
1726	>	w.parker = null;
1727	>	U.putObject(wt, PARKBLOCKER, null);
1728	>	}
1729	>	}
1730	>	if ((h >= 0 \|\| (h = w.hint) >= 0) &&
1731	>	(ws = workQueues) != null && h < ws.length &&
1732	>	(q = ws[h]) != null) { // signal others before retry
1733	>	WorkQueue v; Thread p; int u, i, s;
1734	>	for (int n = (config & SMASK) - 1;;) {
1735	>	int idleCount = (w.eventCount < 0) ? 0 : -1;
1736	>	if (((s = idleCount - q.base + q.top) <= n &&
1737	>	(n = s) <= 0) \|\|
1738	>	(u = (int)((c = ctl) >>> 32)) >= 0 \|\|
1739	>	(e = (int)c) <= 0 \|\| m < (i = e & SMASK) \|\|
1740	>	(v = ws[i]) == null)
1741	>	break;
1742	>	long nc = (((long)(v.nextWait & E_MASK)) \|
1743	>	((long)(u + UAC_UNIT) << 32));
1744	>	if (v.eventCount != (e \| INT_SIGN) \|\|
1745	>	!U.compareAndSwapLong(this, CTL, c, nc))
1746	>	break;
1747	>	v.hint = h;
1748		v.eventCount = (e + E_SEQ) & E_MASK;
1749		if ((p = v.parker) != null)
1750		U.unpark(p);
1751	+	if (--n <= 0)
1752	+	break;
1753		}
1754		}
1755		}
1630	–	else if (ec >= 0) { // try to enqueue/inactivate
1631	–	long nc = (long)ec \| ((c - AC_UNIT) & (AC_MASK\|TC_MASK));
1632	–	w.nextWait = e;
1633	–	w.eventCount = ec \| INT_SIGN; // mark as inactive
1634	–	if (ctl != c \|\| !U.compareAndSwapLong(this, CTL, c, nc))
1635	–	w.eventCount = ec; // unmark on CAS failure
1636	–	else {
1637	–	if ((ns = w.nsteals) != 0) {
1638	–	w.nsteals = 0; // set rescans if ran task
1639	–	w.rescans = (a > 0) ? 0 : a + parallelism;
1640	–	w.totalSteals += ns;
1641	–	}
1642	–	if (a == 1 - parallelism) // quiescent
1643	–	idleAwaitWork(w, nc, c);
1644	–	}
1645	–	}
1646	–	else if (w.eventCount < 0) { // already queued
1647	–	int ac = a + parallelism;
1648	–	if ((nr = w.rescans) > 0) // continue rescanning
1649	–	w.rescans = (ac < nr) ? ac : nr - 1;
1650	–	else if (((w.seed >>> 16) & ac) == 0) { // randomize park
1651	–	Thread.interrupted(); // clear status
1652	–	Thread wt = Thread.currentThread();
1653	–	U.putObject(wt, PARKBLOCKER, this);
1654	–	w.parker = wt; // emulate LockSupport.park
1655	–	if (w.eventCount < 0) // recheck
1656	–	U.park(false, 0L);
1657	–	w.parker = null;
1658	–	U.putObject(wt, PARKBLOCKER, null);
1659	–	}
1660	–	}
1756		}
1757		return null;
1758		}
#	Line 1675 \| Line 1770 \| public class ForkJoinPool extends Abstra
1770		* @param prevCtl the ctl value to restore if thread is terminated
1771		*/
1772		private void idleAwaitWork(WorkQueue w, long currentCtl, long prevCtl) {
1773	<	if (w.eventCount < 0 && !tryTerminate(false, false) &&
1774	<	(int)prevCtl != 0 && !hasQueuedSubmissions() && ctl == currentCtl) {
1773	>	if (w != null && w.eventCount < 0 &&
1774	>	!tryTerminate(false, false) && (int)prevCtl != 0 &&
1775	>	ctl == currentCtl) {
1776		int dc = -(short)(currentCtl >>> TC_SHIFT);
1777		long parkTime = dc < 0 ? FAST_IDLE_TIMEOUT: (dc + 1) * IDLE_TIMEOUT;
1778	<	long deadline = System.nanoTime() + parkTime - 100000L; // 1ms slop
1778	>	long deadline = System.nanoTime() + parkTime - TIMEOUT_SLOP;
1779		Thread wt = Thread.currentThread();
1780		while (ctl == currentCtl) {
1781		Thread.interrupted(); // timed variant of version in scan()
#	Line 1694 \| Line 1790 \| public class ForkJoinPool extends Abstra
1790		if (deadline - System.nanoTime() <= 0L &&
1791		U.compareAndSwapLong(this, CTL, currentCtl, prevCtl)) {
1792		w.eventCount = (w.eventCount + E_SEQ) \| E_MASK;
1793	<	w.runState = -1; // shrink
1793	>	w.hint = -1;
1794	>	w.qlock = -1; // shrink
1795		break;
1796		}
1797		}
#	Line 1702 \| Line 1799 \| public class ForkJoinPool extends Abstra
1799		}
1800
1801		/**
1802	+	* Scans through queues looking for work while joining a task; if
1803	+	* any present, signals. May return early if more signalling is
1804	+	* detectably unneeded.
1805	+	*
1806	+	* @param task return early if done
1807	+	* @param origin an index to start scan
1808	+	*/
1809	+	private void helpSignal(ForkJoinTask<?> task, int origin) {
1810	+	WorkQueue[] ws; WorkQueue w; Thread p; long c; int m, u, e, i, s;
1811	+	if (task != null && task.status >= 0 &&
1812	+	(u = (int)(ctl >>> 32)) < 0 && (u >> UAC_SHIFT) < 0 &&
1813	+	(ws = workQueues) != null && (m = ws.length - 1) >= 0) {
1814	+	outer: for (int k = origin, j = m; j >= 0; --j) {
1815	+	WorkQueue q = ws[k++ & m];
1816	+	for (int n = m;;) { // limit to at most m signals
1817	+	if (task.status < 0)
1818	+	break outer;
1819	+	if (q == null \|\|
1820	+	((s = -q.base + q.top) <= n && (n = s) <= 0))
1821	+	break;
1822	+	if ((u = (int)((c = ctl) >>> 32)) >= 0 \|\|
1823	+	(e = (int)c) <= 0 \|\| m < (i = e & SMASK) \|\|
1824	+	(w = ws[i]) == null)
1825	+	break outer;
1826	+	long nc = (((long)(w.nextWait & E_MASK)) \|
1827	+	((long)(u + UAC_UNIT) << 32));
1828	+	if (w.eventCount != (e \| INT_SIGN))
1829	+	break outer;
1830	+	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1831	+	w.eventCount = (e + E_SEQ) & E_MASK;
1832	+	if ((p = w.parker) != null)
1833	+	U.unpark(p);
1834	+	if (--n <= 0)
1835	+	break;
1836	+	}
1837	+	}
1838	+	}
1839	+	}
1840	+	}
1841	+
1842	+	/**
1843		* Tries to locate and execute tasks for a stealer of the given
1844		* task, or in turn one of its stealers, Traces currentSteal ->
1845		* currentJoin links looking for a thread working on a descendant
#	Line 1732 \| Line 1870 \| public class ForkJoinPool extends Abstra
1870		}
1871		if ((ws = workQueues) == null \|\| (m = ws.length - 1) <= 0)
1872		break restart; // shutting down
1873	<	if ((v = ws[h = (j.stealHint \| 1) & m]) == null \|\|
1873	>	if ((v = ws[h = (j.hint \| 1) & m]) == null \|\|
1874		v.currentSteal != subtask) {
1875		for (int origin = h;;) { // find stealer
1876		if (((h = (h + 2) & m) & 15) == 1 &&
#	Line 1740 \| Line 1878 \| public class ForkJoinPool extends Abstra
1878		continue restart; // occasional staleness check
1879		if ((v = ws[h]) != null &&
1880		v.currentSteal == subtask) {
1881	<	j.stealHint = h; // save hint
1881	>	j.hint = h; // save hint
1882		break;
1883		}
1884		if (h == origin)
#	Line 1788 \| Line 1926 \| public class ForkJoinPool extends Abstra
1926		}
1927
1928		/**
1929	<	* If task is at base of some steal queue, steals and executes it.
1929	>	* Analog of tryHelpStealer for CountedCompleters. Tries to steal
1930	>	* and run tasks within the target's computation.
1931		*
1932	<	* @param joiner the joining worker
1933	<	* @param task the task
1932	>	* @param task the task to join
1933	>	* @param mode if shared, exit upon completing any task
1934	>	* if all workers are active
1935		*/
1936	<	private void tryPollForAndExec(WorkQueue joiner, ForkJoinTask<?> task) {
1937	<	WorkQueue[] ws;
1938	<	if ((ws = workQueues) != null) {
1939	<	for (int j = 1; j < ws.length && task.status >= 0; j += 2) {
1940	<	WorkQueue q = ws[j];
1941	<	if (q != null && q.pollFor(task)) {
1942	<	joiner.runSubtask(task);
1943	<	break;
1936	>	private int helpComplete(ForkJoinTask<?> task, int mode) {
1937	>	WorkQueue[] ws; WorkQueue q; int m, n, s, u;
1938	>	if (task != null && (ws = workQueues) != null &&
1939	>	(m = ws.length - 1) >= 0) {
1940	>	for (int j = 1, origin = j;;) {
1941	>	if ((s = task.status) < 0)
1942	>	return s;
1943	>	if ((q = ws[j & m]) != null && q.pollAndExecCC(task)) {
1944	>	origin = j;
1945	>	if (mode == SHARED_QUEUE &&
1946	>	((u = (int)(ctl >>> 32)) >= 0 \|\| (u >> UAC_SHIFT) >= 0))
1947	>	break;
1948		}
1949	+	else if ((j = (j + 2) & m) == origin)
1950	+	break;
1951		}
1952		}
1953	+	return 0;
1954		}
1955
1956		/**
1957		* Tries to decrement active count (sometimes implicitly) and
1958		* possibly release or create a compensating worker in preparation
1959		* for blocking. Fails on contention or termination. Otherwise,
1960	<	* adds a new thread if no idle workers are available and either
1961	<	* pool would become completely starved or: (at least half
1815	<	* starved, and fewer than 50% spares exist, and there is at least
1816	<	* one task apparently available). Even though the availability
1817	<	* check requires a full scan, it is worthwhile in reducing false
1818	<	* alarms.
1819	<	*
1820	<	* @param task if non-null, a task being waited for
1821	<	* @param blocker if non-null, a blocker being waited for
1822	<	* @return true if the caller can block, else should recheck and retry
1960	>	* adds a new thread if no idle workers are available and pool
1961	>	* may become starved.
1962		*/
1963	<	final boolean tryCompensate(ForkJoinTask<?> task, ManagedBlocker blocker) {
1964	<	int pc = parallelism, e;
1965	<	long c = ctl;
1966	<	WorkQueue[] ws = workQueues;
1967	<	if ((e = (int)c) >= 0 && ws != null) {
1968	<	int u, a, ac, hc;
1969	<	int tc = (short)((u = (int)(c >>> 32)) >>> UTC_SHIFT) + pc;
1970	<	boolean replace = false;
1971	<	if ((a = u >> UAC_SHIFT) <= 0) {
1972	<	if ((ac = a + pc) <= 1)
1973	<	replace = true;
1974	<	else if ((e > 0 \|\| (task != null &&
1975	<	ac <= (hc = pc >>> 1) && tc < pc + hc))) {
1837	<	WorkQueue w;
1838	<	for (int j = 0; j < ws.length; ++j) {
1839	<	if ((w = ws[j]) != null && !w.isEmpty()) {
1840	<	replace = true;
1841	<	break; // in compensation range and tasks available
1842	<	}
1843	<	}
1963	>	final boolean tryCompensate() {
1964	>	int pc = config & SMASK, e, i, tc; long c;
1965	>	WorkQueue[] ws; WorkQueue w; Thread p;
1966	>	if ((ws = workQueues) != null && (e = (int)(c = ctl)) >= 0) {
1967	>	if (e != 0 && (i = e & SMASK) < ws.length &&
1968	>	(w = ws[i]) != null && w.eventCount == (e \| INT_SIGN)) {
1969	>	long nc = ((long)(w.nextWait & E_MASK) \|
1970	>	(c & (AC_MASK\|TC_MASK)));
1971	>	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1972	>	w.eventCount = (e + E_SEQ) & E_MASK;
1973	>	if ((p = w.parker) != null)
1974	>	U.unpark(p);
1975	>	return true; // replace with idle worker
1976		}
1977		}
1978	<	if ((task == null \|\| task.status >= 0) && // recheck need to block
1979	<	(blocker == null \|\| !blocker.isReleasable()) && ctl == c) {
1980	<	if (!replace) { // no compensation
1981	<	long nc = ((c - AC_UNIT) & AC_MASK) \| (c & ~AC_MASK);
1982	<	if (U.compareAndSwapLong(this, CTL, c, nc))
1983	<	return true;
1984	<	}
1985	<	else if (e != 0) { // release an idle worker
1986	<	WorkQueue w; Thread p; int i;
1987	<	if ((i = e & SMASK) < ws.length && (w = ws[i]) != null) {
1988	<	long nc = ((long)(w.nextWait & E_MASK) \|
1989	<	(c & (AC_MASK\|TC_MASK)));
1990	<	if (w.eventCount == (e \| INT_SIGN) &&
1991	<	U.compareAndSwapLong(this, CTL, c, nc)) {
1992	<	w.eventCount = (e + E_SEQ) & E_MASK;
1993	<	if ((p = w.parker) != null)
1862	<	U.unpark(p);
1978	>	else if ((tc = (short)(c >>> TC_SHIFT)) >= 0 &&
1979	>	(int)(c >> AC_SHIFT) + pc > 1) {
1980	>	long nc = ((c - AC_UNIT) & AC_MASK) \| (c & ~AC_MASK);
1981	>	if (U.compareAndSwapLong(this, CTL, c, nc))
1982	>	return true; // no compensation
1983	>	}
1984	>	else if (tc + pc < MAX_CAP) {
1985	>	long nc = ((c + TC_UNIT) & TC_MASK) \| (c & ~TC_MASK);
1986	>	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1987	>	ForkJoinWorkerThreadFactory fac;
1988	>	Throwable ex = null;
1989	>	ForkJoinWorkerThread wt = null;
1990	>	try {
1991	>	if ((fac = factory) != null &&
1992	>	(wt = fac.newThread(this)) != null) {
1993	>	wt.start();
1994		return true;
1995		}
1996	+	} catch (Throwable rex) {
1997	+	ex = rex;
1998		}
1999	<	}
1867	<	else if (tc < MAX_CAP) { // create replacement
1868	<	long nc = ((c + TC_UNIT) & TC_MASK) \| (c & ~TC_MASK);
1869	<	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1870	<	addWorker();
1871	<	return true;
1872	<	}
1999	>	deregisterWorker(wt, ex); // clean up and return false
2000		}
2001		}
2002		}
#	Line 1884 \| Line 2011 \| public class ForkJoinPool extends Abstra
2011		* @return task status on exit
2012		*/
2013		final int awaitJoin(WorkQueue joiner, ForkJoinTask<?> task) {
2014	<	int s;
2015	<	if ((s = task.status) >= 0) {
2014	>	int s = 0;
2015	>	if (joiner != null && task != null && (s = task.status) >= 0) {
2016		ForkJoinTask<?> prevJoin = joiner.currentJoin;
2017		joiner.currentJoin = task;
2018	<	long startTime = 0L;
2019	<	for (int k = 0;;) {
2020	<	if ((s = (joiner.isEmpty() ? // try to help
2021	<	tryHelpStealer(joiner, task) :
2022	<	joiner.tryRemoveAndExec(task))) == 0 &&
2018	>	do {} while ((s = task.status) >= 0 && !joiner.isEmpty() &&
2019	>	joiner.tryRemoveAndExec(task)); // process local tasks
2020	>	if (s >= 0 && (s = task.status) >= 0) {
2021	>	helpSignal(task, joiner.poolIndex);
2022	>	if ((s = task.status) >= 0 &&
2023	>	(task instanceof CountedCompleter))
2024	>	s = helpComplete(task, LIFO_QUEUE);
2025	>	}
2026	>	while (s >= 0 && (s = task.status) >= 0) {
2027	>	if ((!joiner.isEmpty() \|\| // try helping
2028	>	(s = tryHelpStealer(joiner, task)) == 0) &&
2029		(s = task.status) >= 0) {
2030	<	if (k == 0) {
2031	<	startTime = System.nanoTime();
2032	<	tryPollForAndExec(joiner, task); // check uncommon case
1900	<	}
1901	<	else if ((k & (MAX_HELP - 1)) == 0 &&
1902	<	System.nanoTime() - startTime >=
1903	<	COMPENSATION_DELAY &&
1904	<	tryCompensate(task, null)) {
1905	<	if (task.trySetSignal()) {
2030	>	helpSignal(task, joiner.poolIndex);
2031	>	if ((s = task.status) >= 0 && tryCompensate()) {
2032	>	if (task.trySetSignal() && (s = task.status) >= 0) {
2033		synchronized (task) {
2034		if (task.status >= 0) {
2035		try { // see ForkJoinTask
#	Line 1919 \| Line 2046 \| public class ForkJoinPool extends Abstra
2046		(this, CTL, c = ctl, c + AC_UNIT));
2047		}
2048		}
1922	–	if (s < 0 \|\| (s = task.status) < 0) {
1923	–	joiner.currentJoin = prevJoin;
1924	–	break;
1925	–	}
1926	–	else if ((k++ & (MAX_HELP - 1)) == MAX_HELP >>> 1)
1927	–	Thread.yield(); // for politeness
2049		}
2050	+	joiner.currentJoin = prevJoin;
2051		}
2052		return s;
2053		}
#	Line 1937 \| Line 2059 \| public class ForkJoinPool extends Abstra
2059		*
2060		* @param joiner the joining worker
2061		* @param task the task
1940	–	* @return task status on exit
2062		*/
2063	<	final int helpJoinOnce(WorkQueue joiner, ForkJoinTask<?> task) {
2063	>	final void helpJoinOnce(WorkQueue joiner, ForkJoinTask<?> task) {
2064		int s;
2065	<	while ((s = task.status) >= 0 &&
2066	<	(joiner.isEmpty() ?
2067	<	tryHelpStealer(joiner, task) :
2068	<	joiner.tryRemoveAndExec(task)) != 0)
2069	<	;
2070	<	return s;
2065	>	if (joiner != null && task != null && (s = task.status) >= 0) {
2066	>	ForkJoinTask<?> prevJoin = joiner.currentJoin;
2067	>	joiner.currentJoin = task;
2068	>	do {} while ((s = task.status) >= 0 && !joiner.isEmpty() &&
2069	>	joiner.tryRemoveAndExec(task));
2070	>	if (s >= 0 && (s = task.status) >= 0) {
2071	>	helpSignal(task, joiner.poolIndex);
2072	>	if ((s = task.status) >= 0 &&
2073	>	(task instanceof CountedCompleter))
2074	>	s = helpComplete(task, LIFO_QUEUE);
2075	>	}
2076	>	if (s >= 0 && joiner.isEmpty()) {
2077	>	do {} while (task.status >= 0 &&
2078	>	tryHelpStealer(joiner, task) > 0);
2079	>	}
2080	>	joiner.currentJoin = prevJoin;
2081	>	}
2082		}
2083
2084		/**
2085		* Returns a (probably) non-empty steal queue, if one is found
2086	<	* during a random, then cyclic scan, else null. This method must
2087	<	* be retried by caller if, by the time it tries to use the queue,
2088	<	* it is empty.
2089	<	*/
2090	<	private WorkQueue findNonEmptyStealQueue(WorkQueue w) {
2091	<	// Similar to loop in scan(), but ignoring submissions
2092	<	int r;
2093	<	if (w == null) // allow external callers
2094	<	r = ThreadLocalRandom.current().nextInt();
2095	<	else {
2096	<	r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
2097	<	}
1966	<	int step = (r >>> 16) \| 1;
1967	<	for (WorkQueue[] ws;;) {
1968	<	int rs = runState, m;
1969	<	if ((ws = workQueues) == null \|\| (m = ws.length - 1) < 1)
1970	<	return null;
1971	<	for (int j = (m + 1) << 2; ; r += step) {
1972	<	WorkQueue q = ws[((r << 1) \| 1) & m];
1973	<	if (q != null && !q.isEmpty())
1974	<	return q;
1975	<	else if (--j < 0) {
1976	<	if (runState == rs)
1977	<	return null;
1978	<	break;
2086	>	* during a scan, else null. This method must be retried by
2087	>	* caller if, by the time it tries to use the queue, it is empty.
2088	>	* @param r a (random) seed for scanning
2089	>	*/
2090	>	private WorkQueue findNonEmptyStealQueue(int r) {
2091	>	for (;;) {
2092	>	int ps = plock, m; WorkQueue[] ws; WorkQueue q;
2093	>	if ((ws = workQueues) != null && (m = ws.length - 1) >= 0) {
2094	>	for (int j = (m + 1) << 2; j >= 0; --j) {
2095	>	if ((q = ws[(((r + j) << 1) \| 1) & m]) != null &&
2096	>	q.base - q.top < 0)
2097	>	return q;
2098		}
2099		}
2100	+	if (plock == ps)
2101	+	return null;
2102		}
2103		}
2104
#	Line 1989 \| Line 2110 \| public class ForkJoinPool extends Abstra
2110		*/
2111		final void helpQuiescePool(WorkQueue w) {
2112		for (boolean active = true;;) {
2113	<	ForkJoinTask<?> localTask; // exhaust local queue
2114	<	while ((localTask = w.nextLocalTask()) != null)
2115	<	localTask.doExec();
2116	<	WorkQueue q = findNonEmptyStealQueue(w);
2117	<	if (q != null) {
2118	<	ForkJoinTask<?> t; int b;
2113	>	long c; WorkQueue q; ForkJoinTask<?> t; int b;
2114	>	while ((t = w.nextLocalTask()) != null) {
2115	>	if (w.base - w.top < 0)
2116	>	signalWork(w);
2117	>	t.doExec();
2118	>	}
2119	>	if ((q = findNonEmptyStealQueue(w.nextSeed())) != null) {
2120		if (!active) { // re-establish active count
1999	–	long c;
2121		active = true;
2122		do {} while (!U.compareAndSwapLong
2123		(this, CTL, c = ctl, c + AC_UNIT));
2124		}
2125	<	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null)
2125	>	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null) {
2126	>	if (q.base - q.top < 0)
2127	>	signalWork(q);
2128		w.runSubtask(t);
2129	+	}
2130		}
2131	<	else {
2132	<	long c;
2133	<	if (active) { // decrement active count without queuing
2131	>	else if (active) { // decrement active count without queuing
2132	>	long nc = (c = ctl) - AC_UNIT;
2133	>	if ((int)(nc >> AC_SHIFT) + (config & SMASK) == 0)
2134	>	return; // bypass decrement-then-increment
2135	>	if (U.compareAndSwapLong(this, CTL, c, nc))
2136		active = false;
2011	–	do {} while (!U.compareAndSwapLong
2012	–	(this, CTL, c = ctl, c -= AC_UNIT));
2013	–	}
2014	–	else
2015	–	c = ctl; // re-increment on exit
2016	–	if ((int)(c >> AC_SHIFT) + parallelism == 0) {
2017	–	do {} while (!U.compareAndSwapLong
2018	–	(this, CTL, c = ctl, c + AC_UNIT));
2019	–	break;
2020	–	}
2137		}
2138	+	else if ((int)((c = ctl) >> AC_SHIFT) + (config & SMASK) == 0 &&
2139	+	U.compareAndSwapLong(this, CTL, c, c + AC_UNIT))
2140	+	return;
2141		}
2142		}
2143
2144		/**
2026	–	* Restricted version of helpQuiescePool for non-FJ callers
2027	–	*/
2028	–	static void externalHelpQuiescePool() {
2029	–	ForkJoinPool p; WorkQueue[] ws; WorkQueue w, q;
2030	–	ForkJoinTask<?> t; int b;
2031	–	int k = submitters.get().seed & SQMASK;
2032	–	if ((p = commonPool) != null &&
2033	–	(ws = p.workQueues) != null &&
2034	–	ws.length > (k &= p.submitMask) &&
2035	–	(w = ws[k]) != null &&
2036	–	(q = p.findNonEmptyStealQueue(w)) != null &&
2037	–	(b = q.base) - q.top < 0 &&
2038	–	(t = q.pollAt(b)) != null)
2039	–	t.doExec();
2040	–	}
2041	–
2042	–	/**
2145		* Gets and removes a local or stolen task for the given worker.
2146		*
2147		* @return a task, if available
#	Line 2049 \| Line 2151 \| public class ForkJoinPool extends Abstra
2151		WorkQueue q; int b;
2152		if ((t = w.nextLocalTask()) != null)
2153		return t;
2154	<	if ((q = findNonEmptyStealQueue(w)) == null)
2154	>	if ((q = findNonEmptyStealQueue(w.nextSeed())) == null)
2155		return null;
2156	<	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null)
2156	>	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null) {
2157	>	if (q.base - q.top < 0)
2158	>	signalWork(q);
2159		return t;
2160	+	}
2161		}
2162		}
2163
2164		/**
2165	<	* Returns the approximate (non-atomic) number of idle threads per
2166	<	* active thread to offset steal queue size for method
2167	<	* ForkJoinTask.getSurplusQueuedTaskCount().
2168	<	*/
2169	<	final int idlePerActive() {
2170	<	// Approximate at powers of two for small values, saturate past 4
2171	<	int p = parallelism;
2172	<	int a = p + (int)(ctl >> AC_SHIFT);
2173	<	return (a > (p >>>= 1) ? 0 :
2174	<	a > (p >>>= 1) ? 1 :
2175	<	a > (p >>>= 1) ? 2 :
2176	<	a > (p >>>= 1) ? 4 :
2177	<	8);
2178	<	}
2179	<
2180	<	/**
2181	<	* Returns approximate submission queue length for the given caller
2182	<	*/
2183	<	static int getEstimatedSubmitterQueueLength() {
2184	<	ForkJoinPool p; WorkQueue[] ws; WorkQueue q;
2185	<	int k = submitters.get().seed & SQMASK;
2186	<	return ((p = commonPool) != null &&
2187	<	p.runState >= 0 &&
2188	<	(ws = p.workQueues) != null &&
2189	<	ws.length > (k &= p.submitMask) &&
2190	<	(q = ws[k]) != null) ?
2191	<	q.queueSize() : 0;
2165	>	* Returns a cheap heuristic guide for task partitioning when
2166	>	* programmers, frameworks, tools, or languages have little or no
2167	>	* idea about task granularity. In essence by offering this
2168	>	* method, we ask users only about tradeoffs in overhead vs
2169	>	* expected throughput and its variance, rather than how finely to
2170	>	* partition tasks.
2171	>	*
2172	>	* In a steady state strict (tree-structured) computation, each
2173	>	* thread makes available for stealing enough tasks for other
2174	>	* threads to remain active. Inductively, if all threads play by
2175	>	* the same rules, each thread should make available only a
2176	>	* constant number of tasks.
2177	>	*
2178	>	* The minimum useful constant is just 1. But using a value of 1
2179	>	* would require immediate replenishment upon each steal to
2180	>	* maintain enough tasks, which is infeasible. Further,
2181	>	* partitionings/granularities of offered tasks should minimize
2182	>	* steal rates, which in general means that threads nearer the top
2183	>	* of computation tree should generate more than those nearer the
2184	>	* bottom. In perfect steady state, each thread is at
2185	>	* approximately the same level of computation tree. However,
2186	>	* producing extra tasks amortizes the uncertainty of progress and
2187	>	* diffusion assumptions.
2188	>	*
2189	>	* So, users will want to use values larger, but not much larger
2190	>	* than 1 to both smooth over transient shortages and hedge
2191	>	* against uneven progress; as traded off against the cost of
2192	>	* extra task overhead. We leave the user to pick a threshold
2193	>	* value to compare with the results of this call to guide
2194	>	* decisions, but recommend values such as 3.
2195	>	*
2196	>	* When all threads are active, it is on average OK to estimate
2197	>	* surplus strictly locally. In steady-state, if one thread is
2198	>	* maintaining say 2 surplus tasks, then so are others. So we can
2199	>	* just use estimated queue length. However, this strategy alone
2200	>	* leads to serious mis-estimates in some non-steady-state
2201	>	* conditions (ramp-up, ramp-down, other stalls). We can detect
2202	>	* many of these by further considering the number of "idle"
2203	>	* threads, that are known to have zero queued tasks, so
2204	>	* compensate by a factor of (#idle/#active) threads.
2205	>	*
2206	>	* Note: The approximation of #busy workers as #active workers is
2207	>	* not very good under current signalling scheme, and should be
2208	>	* improved.
2209	>	*/
2210	>	static int getSurplusQueuedTaskCount() {
2211	>	Thread t; ForkJoinWorkerThread wt; ForkJoinPool pool; WorkQueue q;
2212	>	if (((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)) {
2213	>	int p = (pool = (wt = (ForkJoinWorkerThread)t).pool).config & SMASK;
2214	>	int n = (q = wt.workQueue).top - q.base;
2215	>	int a = (int)(pool.ctl >> AC_SHIFT) + p;
2216	>	return n - (a > (p >>>= 1) ? 0 :
2217	>	a > (p >>>= 1) ? 1 :
2218	>	a > (p >>>= 1) ? 2 :
2219	>	a > (p >>>= 1) ? 4 :
2220	>	8);
2221	>	}
2222	>	return 0;
2223		}
2224
2225		// Termination
#	Line 2103 \| Line 2239 \| public class ForkJoinPool extends Abstra
2239		* @return true if now terminating or terminated
2240		*/
2241		private boolean tryTerminate(boolean now, boolean enable) {
2242	<	Mutex lock = this.lock;
2242	>	int ps;
2243	>	if (this == common) // cannot shut down
2244	>	return false;
2245	>	if ((ps = plock) >= 0) { // enable by setting plock
2246	>	if (!enable)
2247	>	return false;
2248	>	if ((ps & PL_LOCK) != 0 \|\|
2249	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
2250	>	ps = acquirePlock();
2251	>	int nps = ((ps + PL_LOCK) & ~SHUTDOWN) \| SHUTDOWN;
2252	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
2253	>	releasePlock(nps);
2254	>	}
2255		for (long c;;) {
2256	<	if (((c = ctl) & STOP_BIT) != 0) { // already terminating
2257	<	if ((short)(c >>> TC_SHIFT) == -parallelism) {
2258	<	lock.lock(); // don't need try/finally
2259	<	termination.signalAll(); // signal when 0 workers
2260	<	lock.unlock();
2256	>	if (((c = ctl) & STOP_BIT) != 0) { // already terminating
2257	>	if ((short)(c >>> TC_SHIFT) == -(config & SMASK)) {
2258	>	synchronized (this) {
2259	>	notifyAll(); // signal when 0 workers
2260	>	}
2261		}
2262		return true;
2263		}
2264	<	if (runState >= 0) { // not yet enabled
2265	<	if (!enable)
2264	>	if (!now) { // check if idle & no tasks
2265	>	WorkQueue[] ws; WorkQueue w;
2266	>	if ((int)(c >> AC_SHIFT) != -(config & SMASK))
2267		return false;
2268	<	lock.lock();
2269	<	runState \|= SHUTDOWN;
2270	<	lock.unlock();
2271	<	}
2272	<	if (!now) { // check if idle & no tasks
2273	<	if ((int)(c >> AC_SHIFT) != -parallelism \|\|
2274	<	hasQueuedSubmissions())
2275	<	return false;
2276	<	// Check for unqueued inactive workers. One pass suffices.
2277	<	WorkQueue[] ws = workQueues; WorkQueue w;
2129	<	if (ws != null) {
2130	<	for (int i = 1; i < ws.length; i += 2) {
2131	<	if ((w = ws[i]) != null && w.eventCount >= 0)
2132	<	return false;
2268	>	if ((ws = workQueues) != null) {
2269	>	for (int i = 0; i < ws.length; ++i) {
2270	>	if ((w = ws[i]) != null) {
2271	>	if (!w.isEmpty()) { // signal unprocessed tasks
2272	>	signalWork(w);
2273	>	return false;
2274	>	}
2275	>	if ((i & 1) != 0 && w.eventCount >= 0)
2276	>	return false; // unqueued inactive worker
2277	>	}
2278		}
2279		}
2280		}
2281		if (U.compareAndSwapLong(this, CTL, c, c \| STOP_BIT)) {
2282		for (int pass = 0; pass < 3; ++pass) {
2283	<	WorkQueue[] ws = workQueues;
2284	<	if (ws != null) {
2140	<	WorkQueue w;
2283	>	WorkQueue[] ws; WorkQueue w; Thread wt;
2284	>	if ((ws = workQueues) != null) {
2285		int n = ws.length;
2286		for (int i = 0; i < n; ++i) {
2287		if ((w = ws[i]) != null) {
2288	<	w.runState = -1;
2288	>	w.qlock = -1;
2289		if (pass > 0) {
2290		w.cancelAll();
2291	<	if (pass > 1)
2292	<	w.interruptOwner();
2291	>	if (pass > 1 && (wt = w.owner) != null) {
2292	>	if (!wt.isInterrupted()) {
2293	>	try {
2294	>	wt.interrupt();
2295	>	} catch (Throwable ignore) {
2296	>	}
2297	>	}
2298	>	U.unpark(wt);
2299	>	}
2300		}
2301		}
2302		}
2303		// Wake up workers parked on event queue
2304		int i, e; long cc; Thread p;
2305		while ((e = (int)(cc = ctl) & E_MASK) != 0 &&
2306	<	(i = e & SMASK) < n &&
2306	>	(i = e & SMASK) < n && i >= 0 &&
2307		(w = ws[i]) != null) {
2308		long nc = ((long)(w.nextWait & E_MASK) \|
2309		((cc + AC_UNIT) & AC_MASK) \|
#	Line 2160 \| Line 2311 \| public class ForkJoinPool extends Abstra
2311		if (w.eventCount == (e \| INT_SIGN) &&
2312		U.compareAndSwapLong(this, CTL, cc, nc)) {
2313		w.eventCount = (e + E_SEQ) & E_MASK;
2314	<	w.runState = -1;
2314	>	w.qlock = -1;
2315		if ((p = w.parker) != null)
2316		U.unpark(p);
2317		}
#	Line 2171 \| Line 2322 \| public class ForkJoinPool extends Abstra
2322		}
2323		}
2324
2325	+	// external operations on common pool
2326	+
2327	+	/**
2328	+	* Returns common pool queue for a thread that has submitted at
2329	+	* least one task.
2330	+	*/
2331	+	static WorkQueue commonSubmitterQueue() {
2332	+	ForkJoinPool p; WorkQueue[] ws; int m; Submitter z;
2333	+	return ((z = submitters.get()) != null &&
2334	+	(p = common) != null &&
2335	+	(ws = p.workQueues) != null &&
2336	+	(m = ws.length - 1) >= 0) ?
2337	+	ws[m & z.seed & SQMASK] : null;
2338	+	}
2339	+
2340	+	/**
2341	+	* Tries to pop the given task from submitter's queue in common pool.
2342	+	*/
2343	+	static boolean tryExternalUnpush(ForkJoinTask<?> t) {
2344	+	ForkJoinPool p; WorkQueue[] ws; WorkQueue q; Submitter z;
2345	+	ForkJoinTask<?>[] a; int m, s;
2346	+	if (t != null &&
2347	+	(z = submitters.get()) != null &&
2348	+	(p = common) != null &&
2349	+	(ws = p.workQueues) != null &&
2350	+	(m = ws.length - 1) >= 0 &&
2351	+	(q = ws[m & z.seed & SQMASK]) != null &&
2352	+	(s = q.top) != q.base &&
2353	+	(a = q.array) != null) {
2354	+	long j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE;
2355	+	if (U.getObject(a, j) == t &&
2356	+	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2357	+	if (q.array == a && q.top == s && // recheck
2358	+	U.compareAndSwapObject(a, j, t, null)) {
2359	+	q.top = s - 1;
2360	+	q.qlock = 0;
2361	+	return true;
2362	+	}
2363	+	q.qlock = 0;
2364	+	}
2365	+	}
2366	+	return false;
2367	+	}
2368	+
2369	+	/**
2370	+	* Tries to pop and run local tasks within the same computation
2371	+	* as the given root. On failure, tries to help complete from
2372	+	* other queues via helpComplete.
2373	+	*/
2374	+	private void externalHelpComplete(WorkQueue q, ForkJoinTask<?> root) {
2375	+	ForkJoinTask<?>[] a; int m;
2376	+	if (q != null && (a = q.array) != null && (m = (a.length - 1)) >= 0 &&
2377	+	root != null && root.status >= 0) {
2378	+	for (;;) {
2379	+	int s, u; Object o; CountedCompleter<?> task = null;
2380	+	if ((s = q.top) - q.base > 0) {
2381	+	long j = ((m & (s - 1)) << ASHIFT) + ABASE;
2382	+	if ((o = U.getObject(a, j)) != null &&
2383	+	(o instanceof CountedCompleter)) {
2384	+	CountedCompleter<?> t = (CountedCompleter<?>)o, r = t;
2385	+	do {
2386	+	if (r == root) {
2387	+	if (U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2388	+	if (q.array == a && q.top == s &&
2389	+	U.compareAndSwapObject(a, j, t, null)) {
2390	+	q.top = s - 1;
2391	+	task = t;
2392	+	}
2393	+	q.qlock = 0;
2394	+	}
2395	+	break;
2396	+	}
2397	+	} while ((r = r.completer) != null);
2398	+	}
2399	+	}
2400	+	if (task != null)
2401	+	task.doExec();
2402	+	if (root.status < 0 \|\|
2403	+	(u = (int)(ctl >>> 32)) >= 0 \|\| (u >> UAC_SHIFT) >= 0)
2404	+	break;
2405	+	if (task == null) {
2406	+	helpSignal(root, q.poolIndex);
2407	+	if (root.status >= 0)
2408	+	helpComplete(root, SHARED_QUEUE);
2409	+	break;
2410	+	}
2411	+	}
2412	+	}
2413	+	}
2414	+
2415	+	/**
2416	+	* Tries to help execute or signal availability of the given task
2417	+	* from submitter's queue in common pool.
2418	+	*/
2419	+	static void externalHelpJoin(ForkJoinTask<?> t) {
2420	+	// Some hard-to-avoid overlap with tryExternalUnpush
2421	+	ForkJoinPool p; WorkQueue[] ws; WorkQueue q, w; Submitter z;
2422	+	ForkJoinTask<?>[] a; int m, s, n;
2423	+	if (t != null &&
2424	+	(z = submitters.get()) != null &&
2425	+	(p = common) != null &&
2426	+	(ws = p.workQueues) != null &&
2427	+	(m = ws.length - 1) >= 0 &&
2428	+	(q = ws[m & z.seed & SQMASK]) != null &&
2429	+	(a = q.array) != null) {
2430	+	int am = a.length - 1;
2431	+	if ((s = q.top) != q.base) {
2432	+	long j = ((am & (s - 1)) << ASHIFT) + ABASE;
2433	+	if (U.getObject(a, j) == t &&
2434	+	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2435	+	if (q.array == a && q.top == s &&
2436	+	U.compareAndSwapObject(a, j, t, null)) {
2437	+	q.top = s - 1;
2438	+	q.qlock = 0;
2439	+	t.doExec();
2440	+	}
2441	+	else
2442	+	q.qlock = 0;
2443	+	}
2444	+	}
2445	+	if (t.status >= 0) {
2446	+	if (t instanceof CountedCompleter)
2447	+	p.externalHelpComplete(q, t);
2448	+	else
2449	+	p.helpSignal(t, q.poolIndex);
2450	+	}
2451	+	}
2452	+	}
2453	+
2454		// Exported methods
2455
2456		// Constructors
#	Line 2242 \| Line 2522 \| public class ForkJoinPool extends Abstra
2522		throw new NullPointerException();
2523		if (parallelism <= 0 \|\| parallelism > MAX_CAP)
2524		throw new IllegalArgumentException();
2245	–	this.parallelism = parallelism;
2525		this.factory = factory;
2526		this.ueh = handler;
2527	<	this.localMode = asyncMode ? FIFO_QUEUE : LIFO_QUEUE;
2527	>	this.config = parallelism \| (asyncMode ? (FIFO_QUEUE << 16) : 0);
2528		long np = (long)(-parallelism); // offset ctl counts
2529		this.ctl = ((np << AC_SHIFT) & AC_MASK) \| ((np << TC_SHIFT) & TC_MASK);
2530	<	// Use nearest power 2 for workQueues size. See Hackers Delight sec 3.2.
2252	<	int n = parallelism - 1;
2253	<	n \|= n >>> 1; n \|= n >>> 2; n \|= n >>> 4; n \|= n >>> 8; n \|= n >>> 16;
2254	<	int size = (n + 1) << 1; // #slots = 2*#workers
2255	<	this.submitMask = size - 1; // room for max # of submit queues
2256	<	this.workQueues = new WorkQueue[size];
2257	<	this.termination = (this.lock = new Mutex()).newCondition();
2258	<	this.stealCount = new AtomicLong();
2259	<	this.nextWorkerNumber = new AtomicInteger();
2260	<	int pn = poolNumberGenerator.incrementAndGet();
2530	>	int pn = nextPoolId();
2531		StringBuilder sb = new StringBuilder("ForkJoinPool-");
2532		sb.append(Integer.toString(pn));
2533		sb.append("-worker-");
2534		this.workerNamePrefix = sb.toString();
2265	–	lock.lock();
2266	–	this.runState = 1; // set init flag
2267	–	lock.unlock();
2535		}
2536
2537		/**
2538	<	* Returns the common pool instance
2538	>	* Constructor for common pool, suitable only for static initialization.
2539	>	* Basically the same as above, but uses smallest possible initial footprint.
2540	>	*/
2541	>	ForkJoinPool(int parallelism, long ctl,
2542	>	ForkJoinWorkerThreadFactory factory,
2543	>	Thread.UncaughtExceptionHandler handler) {
2544	>	this.config = parallelism;
2545	>	this.ctl = ctl;
2546	>	this.factory = factory;
2547	>	this.ueh = handler;
2548	>	this.workerNamePrefix = "ForkJoinPool.commonPool-worker-";
2549	>	}
2550	>
2551	>	/**
2552	>	* Returns the common pool instance. This pool is statically
2553	>	* constructed; its run state is unaffected by attempts to {@link
2554	>	* #shutdown} or {@link #shutdownNow}. However this pool and any
2555	>	* ongoing processing are automatically terminated upon program
2556	>	* {@link System#exit}. Any program that relies on asynchronous
2557	>	* task processing to complete before program termination should
2558	>	* invoke {@code commonPool().}{@link #awaitQuiescence}, before
2559	>	* exit.
2560		*
2561		* @return the common pool instance
2562	+	* @since 1.8
2563		*/
2564		public static ForkJoinPool commonPool() {
2565	<	ForkJoinPool p;
2566	<	return (p = commonPool) != null? p : ensureCommonPool();
2278	<	}
2279	<
2280	<	private static ForkJoinPool ensureCommonPool() {
2281	<	ForkJoinPool p;
2282	<	if ((p = commonPool) == null) {
2283	<	final Mutex lock = initializationLock;
2284	<	lock.lock();
2285	<	try {
2286	<	if ((p = commonPool) == null) {
2287	<	p = commonPool = new ForkJoinPool(commonPoolParallelism,
2288	<	commonPoolFactory,
2289	<	commonPoolUEH, false);
2290	<	// use a more informative name string for workers
2291	<	p.workerNamePrefix = "ForkJoinPool.commonPool-worker-";
2292	<	}
2293	<	} finally {
2294	<	lock.unlock();
2295	<	}
2296	<	}
2297	<	return p;
2565	>	// assert common != null : "static init error";
2566	>	return common;
2567		}
2568
2569		// Execution methods
#	Line 2318 \| Line 2587 \| public class ForkJoinPool extends Abstra
2587		public <T> T invoke(ForkJoinTask<T> task) {
2588		if (task == null)
2589		throw new NullPointerException();
2590	<	doSubmit(task);
2590	>	externalPush(task);
2591		return task.join();
2592		}
2593
#	Line 2333 \| Line 2602 \| public class ForkJoinPool extends Abstra
2602		public void execute(ForkJoinTask<?> task) {
2603		if (task == null)
2604		throw new NullPointerException();
2605	<	doSubmit(task);
2605	>	externalPush(task);
2606		}
2607
2608		// AbstractExecutorService methods
#	Line 2351 \| Line 2620 \| public class ForkJoinPool extends Abstra
2620		job = (ForkJoinTask<?>) task;
2621		else
2622		job = new ForkJoinTask.AdaptedRunnableAction(task);
2623	<	doSubmit(job);
2623	>	externalPush(job);
2624		}
2625
2626		/**
#	Line 2366 \| Line 2635 \| public class ForkJoinPool extends Abstra
2635		public <T> ForkJoinTask<T> submit(ForkJoinTask<T> task) {
2636		if (task == null)
2637		throw new NullPointerException();
2638	<	doSubmit(task);
2638	>	externalPush(task);
2639		return task;
2640		}
2641
#	Line 2377 \| Line 2646 \| public class ForkJoinPool extends Abstra
2646		*/
2647		public <T> ForkJoinTask<T> submit(Callable<T> task) {
2648		ForkJoinTask<T> job = new ForkJoinTask.AdaptedCallable<T>(task);
2649	<	doSubmit(job);
2649	>	externalPush(job);
2650		return job;
2651		}
2652
#	Line 2388 \| Line 2657 \| public class ForkJoinPool extends Abstra
2657		*/
2658		public <T> ForkJoinTask<T> submit(Runnable task, T result) {
2659		ForkJoinTask<T> job = new ForkJoinTask.AdaptedRunnable<T>(task, result);
2660	<	doSubmit(job);
2660	>	externalPush(job);
2661		return job;
2662		}
2663
#	Line 2405 \| Line 2674 \| public class ForkJoinPool extends Abstra
2674		job = (ForkJoinTask<?>) task;
2675		else
2676		job = new ForkJoinTask.AdaptedRunnableAction(task);
2677	<	doSubmit(job);
2677	>	externalPush(job);
2678		return job;
2679		}
2680
#	Line 2427 \| Line 2696 \| public class ForkJoinPool extends Abstra
2696		try {
2697		for (Callable<T> t : tasks) {
2698		ForkJoinTask<T> f = new ForkJoinTask.AdaptedCallable<T>(t);
2699	<	doSubmit(f);
2699	>	externalPush(f);
2700		fs.add(f);
2701		}
2702		for (ForkJoinTask<T> f : fs)
#	Line 2466 \| Line 2735 \| public class ForkJoinPool extends Abstra
2735		* @return the targeted parallelism level of this pool
2736		*/
2737		public int getParallelism() {
2738	<	return parallelism;
2738	>	return config & SMASK;
2739		}
2740
2741		/**
2742		* Returns the targeted parallelism level of the common pool.
2743		*
2744		* @return the targeted parallelism level of the common pool
2745	+	* @since 1.8
2746		*/
2747		public static int getCommonPoolParallelism() {
2748	<	return commonPoolParallelism;
2748	>	return commonParallelism;
2749		}
2750
2751		/**
#	Line 2487 \| Line 2757 \| public class ForkJoinPool extends Abstra
2757		* @return the number of worker threads
2758		*/
2759		public int getPoolSize() {
2760	<	return parallelism + (short)(ctl >>> TC_SHIFT);
2760	>	return (config & SMASK) + (short)(ctl >>> TC_SHIFT);
2761		}
2762
2763		/**
#	Line 2497 \| Line 2767 \| public class ForkJoinPool extends Abstra
2767		* @return {@code true} if this pool uses async mode
2768		*/
2769		public boolean getAsyncMode() {
2770	<	return localMode != 0;
2770	>	return (config >>> 16) == FIFO_QUEUE;
2771		}
2772
2773		/**
#	Line 2528 \| Line 2798 \| public class ForkJoinPool extends Abstra
2798		* @return the number of active threads
2799		*/
2800		public int getActiveThreadCount() {
2801	<	int r = parallelism + (int)(ctl >> AC_SHIFT);
2801	>	int r = (config & SMASK) + (int)(ctl >> AC_SHIFT);
2802		return (r <= 0) ? 0 : r; // suppress momentarily negative values
2803		}
2804
#	Line 2544 \| Line 2814 \| public class ForkJoinPool extends Abstra
2814		* @return {@code true} if all threads are currently idle
2815		*/
2816		public boolean isQuiescent() {
2817	<	return (int)(ctl >> AC_SHIFT) + parallelism == 0;
2817	>	return (int)(ctl >> AC_SHIFT) + (config & SMASK) == 0;
2818		}
2819
2820		/**
#	Line 2559 \| Line 2829 \| public class ForkJoinPool extends Abstra
2829		* @return the number of steals
2830		*/
2831		public long getStealCount() {
2832	<	long count = stealCount.get();
2832	>	long count = stealCount;
2833		WorkQueue[] ws; WorkQueue w;
2834		if ((ws = workQueues) != null) {
2835		for (int i = 1; i < ws.length; i += 2) {
2836		if ((w = ws[i]) != null)
2837	<	count += w.totalSteals;
2837	>	count += w.nsteals;
2838		}
2839		}
2840		return count;
#	Line 2689 \| Line 2959 \| public class ForkJoinPool extends Abstra
2959		public String toString() {
2960		// Use a single pass through workQueues to collect counts
2961		long qt = 0L, qs = 0L; int rc = 0;
2962	<	long st = stealCount.get();
2962	>	long st = stealCount;
2963		long c = ctl;
2964		WorkQueue[] ws; WorkQueue w;
2965		if ((ws = workQueues) != null) {
#	Line 2700 \| Line 2970 \| public class ForkJoinPool extends Abstra
2970		qs += size;
2971		else {
2972		qt += size;
2973	<	st += w.totalSteals;
2973	>	st += w.nsteals;
2974		if (w.isApparentlyUnblocked())
2975		++rc;
2976		}
2977		}
2978		}
2979		}
2980	<	int pc = parallelism;
2980	>	int pc = (config & SMASK);
2981		int tc = pc + (short)(c >>> TC_SHIFT);
2982		int ac = pc + (int)(c >> AC_SHIFT);
2983		if (ac < 0) // ignore transient negative
#	Line 2716 \| Line 2986 \| public class ForkJoinPool extends Abstra
2986		if ((c & STOP_BIT) != 0)
2987		level = (tc == 0) ? "Terminated" : "Terminating";
2988		else
2989	<	level = runState < 0 ? "Shutting down" : "Running";
2989	>	level = plock < 0 ? "Shutting down" : "Running";
2990		return super.toString() +
2991		"[" + level +
2992		", parallelism = " + pc +
#	Line 2733 \| Line 3003 \| public class ForkJoinPool extends Abstra
3003		* Possibly initiates an orderly shutdown in which previously
3004		* submitted tasks are executed, but no new tasks will be
3005		* accepted. Invocation has no effect on execution state if this
3006	<	* is the {@link #commonPool}, and no additional effect if
3006	>	* is the {@link #commonPool()}, and no additional effect if
3007		* already shut down. Tasks that are in the process of being
3008		* submitted concurrently during the course of this method may or
3009		* may not be rejected.
#	Line 2745 \| Line 3015 \| public class ForkJoinPool extends Abstra
3015		*/
3016		public void shutdown() {
3017		checkPermission();
3018	<	if (this != commonPool)
2749	<	tryTerminate(false, true);
3018	>	tryTerminate(false, true);
3019		}
3020
3021		/**
3022		* Possibly attempts to cancel and/or stop all tasks, and reject
3023		* all subsequently submitted tasks. Invocation has no effect on
3024	<	* execution state if this is the {@link #commonPool}, and no
3024	>	* execution state if this is the {@link #commonPool()}, and no
3025		* additional effect if already shut down. Otherwise, tasks that
3026		* are in the process of being submitted or executed concurrently
3027		* during the course of this method may or may not be
#	Line 2769 \| Line 3038 \| public class ForkJoinPool extends Abstra
3038		*/
3039		public List<Runnable> shutdownNow() {
3040		checkPermission();
3041	<	if (this != commonPool)
2773	<	tryTerminate(true, true);
3041	>	tryTerminate(true, true);
3042		return Collections.emptyList();
3043		}
3044
#	Line 2782 \| Line 3050 \| public class ForkJoinPool extends Abstra
3050		public boolean isTerminated() {
3051		long c = ctl;
3052		return ((c & STOP_BIT) != 0L &&
3053	<	(short)(c >>> TC_SHIFT) == -parallelism);
3053	>	(short)(c >>> TC_SHIFT) == -(config & SMASK));
3054		}
3055
3056		/**
#	Line 2790 \| Line 3058 \| public class ForkJoinPool extends Abstra
3058		* commenced but not yet completed. This method may be useful for
3059		* debugging. A return of {@code true} reported a sufficient
3060		* period after shutdown may indicate that submitted tasks have
3061	<	* ignored or suppressed interruption, or are waiting for IO,
3061	>	* ignored or suppressed interruption, or are waiting for I/O,
3062		* causing this executor not to properly terminate. (See the
3063		* advisory notes for class {@link ForkJoinTask} stating that
3064		* tasks should not normally entail blocking operations. But if
#	Line 2801 \| Line 3069 \| public class ForkJoinPool extends Abstra
3069		public boolean isTerminating() {
3070		long c = ctl;
3071		return ((c & STOP_BIT) != 0L &&
3072	<	(short)(c >>> TC_SHIFT) != -parallelism);
3072	>	(short)(c >>> TC_SHIFT) != -(config & SMASK));
3073		}
3074
3075		/**
#	Line 2810 \| Line 3078 \| public class ForkJoinPool extends Abstra
3078		* @return {@code true} if this pool has been shut down
3079		*/
3080		public boolean isShutdown() {
3081	<	return runState < 0;
3081	>	return plock < 0;
3082		}
3083
3084		/**
3085	<	* Blocks until all tasks have completed execution after a shutdown
3086	<	* request, or the timeout occurs, or the current thread is
3087	<	* interrupted, whichever happens first.
3085	>	* Blocks until all tasks have completed execution after a
3086	>	* shutdown request, or the timeout occurs, or the current thread
3087	>	* is interrupted, whichever happens first. Because the {@link
3088	>	* #commonPool()} never terminates until program shutdown, when
3089	>	* applied to the common pool, this method is equivalent to {@link
3090	>	* #awaitQuiescence} but always returns {@code false}.
3091		*
3092		* @param timeout the maximum time to wait
3093		* @param unit the time unit of the timeout argument
#	Line 2826 \| Line 3097 \| public class ForkJoinPool extends Abstra
3097		*/
3098		public boolean awaitTermination(long timeout, TimeUnit unit)
3099		throws InterruptedException {
3100	+	if (Thread.interrupted())
3101	+	throw new InterruptedException();
3102	+	if (this == common) {
3103	+	awaitQuiescence(timeout, unit);
3104	+	return false;
3105	+	}
3106		long nanos = unit.toNanos(timeout);
3107	<	final Mutex lock = this.lock;
3108	<	lock.lock();
3109	<	try {
3110	<	for (;;) {
3111	<	if (isTerminated())
3112	<	return true;
3113	<	if (nanos <= 0)
3107	>	if (isTerminated())
3108	>	return true;
3109	>	long startTime = System.nanoTime();
3110	>	boolean terminated = false;
3111	>	synchronized (this) {
3112	>	for (long waitTime = nanos, millis = 0L;;) {
3113	>	if (terminated = isTerminated() \|\|
3114	>	waitTime <= 0L \|\|
3115	>	(millis = unit.toMillis(waitTime)) <= 0L)
3116	>	break;
3117	>	wait(millis);
3118	>	waitTime = nanos - (System.nanoTime() - startTime);
3119	>	}
3120	>	}
3121	>	return terminated;
3122	>	}
3123	>
3124	>	/**
3125	>	* If called by a ForkJoinTask operating in this pool, equivalent
3126	>	* in effect to {@link ForkJoinTask#helpQuiesce}. Otherwise,
3127	>	* waits and/or attempts to assist performing tasks until this
3128	>	* pool {@link #isQuiescent} or the indicated timeout elapses.
3129	>	*
3130	>	* @param timeout the maximum time to wait
3131	>	* @param unit the time unit of the timeout argument
3132	>	* @return {@code true} if quiescent; {@code false} if the
3133	>	* timeout elapsed.
3134	>	*/
3135	>	public boolean awaitQuiescence(long timeout, TimeUnit unit) {
3136	>	long nanos = unit.toNanos(timeout);
3137	>	ForkJoinWorkerThread wt;
3138	>	Thread thread = Thread.currentThread();
3139	>	if ((thread instanceof ForkJoinWorkerThread) &&
3140	>	(wt = (ForkJoinWorkerThread)thread).pool == this) {
3141	>	helpQuiescePool(wt.workQueue);
3142	>	return true;
3143	>	}
3144	>	long startTime = System.nanoTime();
3145	>	WorkQueue[] ws;
3146	>	int r = 0, m;
3147	>	boolean found = true;
3148	>	while (!isQuiescent() && (ws = workQueues) != null &&
3149	>	(m = ws.length - 1) >= 0) {
3150	>	if (!found) {
3151	>	if ((System.nanoTime() - startTime) > nanos)
3152		return false;
3153	<	nanos = termination.awaitNanos(nanos);
3153	>	Thread.yield(); // cannot block
3154	>	}
3155	>	found = false;
3156	>	for (int j = (m + 1) << 2; j >= 0; --j) {
3157	>	ForkJoinTask<?> t; WorkQueue q; int b;
3158	>	if ((q = ws[r++ & m]) != null && (b = q.base) - q.top < 0) {
3159	>	found = true;
3160	>	if ((t = q.pollAt(b)) != null) {
3161	>	if (q.base - q.top < 0)
3162	>	signalWork(q);
3163	>	t.doExec();
3164	>	}
3165	>	break;
3166	>	}
3167		}
2840	–	} finally {
2841	–	lock.unlock();
3168		}
3169	+	return true;
3170	+	}
3171	+
3172	+	/**
3173	+	* Waits and/or attempts to assist performing tasks indefinitely
3174	+	* until the {@link #commonPool()} {@link #isQuiescent}
3175	+	*/
3176	+	static void quiesceCommonPool() {
3177	+	common.awaitQuiescence(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
3178		}
3179
3180		/**
#	Line 2938 \| Line 3273 \| public class ForkJoinPool extends Abstra
3273		public static void managedBlock(ManagedBlocker blocker)
3274		throws InterruptedException {
3275		Thread t = Thread.currentThread();
3276	<	ForkJoinPool p = ((t instanceof ForkJoinWorkerThread) ?
3277	<	((ForkJoinWorkerThread)t).pool : null);
3278	<	while (!blocker.isReleasable()) {
3279	<	if (p == null \|\| p.tryCompensate(null, blocker)) {
3280	<	try {
3281	<	do {} while (!blocker.isReleasable() && !blocker.block());
3282	<	} finally {
3283	<	if (p != null)
3276	>	if (t instanceof ForkJoinWorkerThread) {
3277	>	ForkJoinPool p = ((ForkJoinWorkerThread)t).pool;
3278	>	while (!blocker.isReleasable()) { // variant of helpSignal
3279	>	WorkQueue[] ws; WorkQueue q; int m, u;
3280	>	if ((ws = p.workQueues) != null && (m = ws.length - 1) >= 0) {
3281	>	for (int i = 0; i <= m; ++i) {
3282	>	if (blocker.isReleasable())
3283	>	return;
3284	>	if ((q = ws[i]) != null && q.base - q.top < 0) {
3285	>	p.signalWork(q);
3286	>	if ((u = (int)(p.ctl >>> 32)) >= 0 \|\|
3287	>	(u >> UAC_SHIFT) >= 0)
3288	>	break;
3289	>	}
3290	>	}
3291	>	}
3292	>	if (p.tryCompensate()) {
3293	>	try {
3294	>	do {} while (!blocker.isReleasable() &&
3295	>	!blocker.block());
3296	>	} finally {
3297		p.incrementActiveCount();
3298	+	}
3299	+	break;
3300		}
2951	–	break;
3301		}
3302		}
3303	+	else {
3304	+	do {} while (!blocker.isReleasable() &&
3305	+	!blocker.block());
3306	+	}
3307		}
3308
3309		// AbstractExecutorService overrides. These rely on undocumented
#	Line 2971 \| Line 3324 \| public class ForkJoinPool extends Abstra
3324		private static final long PARKBLOCKER;
3325		private static final int ABASE;
3326		private static final int ASHIFT;
3327	+	private static final long STEALCOUNT;
3328	+	private static final long PLOCK;
3329	+	private static final long INDEXSEED;
3330	+	private static final long QLOCK;
3331
3332		static {
3333	<	poolNumberGenerator = new AtomicInteger();
2977	<	nextSubmitterSeed = new AtomicInteger(0x55555555);
2978	<	modifyThreadPermission = new RuntimePermission("modifyThread");
2979	<	defaultForkJoinWorkerThreadFactory =
2980	<	new DefaultForkJoinWorkerThreadFactory();
2981	<	submitters = new ThreadSubmitter();
2982	<	initializationLock = new Mutex();
2983	<	int s;
3333	>	int s; // initialize field offsets for CAS etc
3334		try {
3335		U = getUnsafe();
3336		Class<?> k = ForkJoinPool.class;
2987	–	Class<?> ak = ForkJoinTask[].class;
3337		CTL = U.objectFieldOffset
3338		(k.getDeclaredField("ctl"));
3339	+	STEALCOUNT = U.objectFieldOffset
3340	+	(k.getDeclaredField("stealCount"));
3341	+	PLOCK = U.objectFieldOffset
3342	+	(k.getDeclaredField("plock"));
3343	+	INDEXSEED = U.objectFieldOffset
3344	+	(k.getDeclaredField("indexSeed"));
3345		Class<?> tk = Thread.class;
3346		PARKBLOCKER = U.objectFieldOffset
3347		(tk.getDeclaredField("parkBlocker"));
3348	+	Class<?> wk = WorkQueue.class;
3349	+	QLOCK = U.objectFieldOffset
3350	+	(wk.getDeclaredField("qlock"));
3351	+	Class<?> ak = ForkJoinTask[].class;
3352		ABASE = U.arrayBaseOffset(ak);
3353		s = U.arrayIndexScale(ak);
3354	+	ASHIFT = 31 - Integer.numberOfLeadingZeros(s);
3355		} catch (Exception e) {
3356		throw new Error(e);
3357		}
3358		if ((s & (s-1)) != 0)
3359		throw new Error("data type scale not a power of two");
3000	–	ASHIFT = 31 - Integer.numberOfLeadingZeros(s);
3360
3361	<	// Establish configuration for default pool
3362	<	try {
3363	<	String pp = System.getProperty(propPrefix + "parallelism");
3364	<	String fp = System.getProperty(propPrefix + "threadFactory");
3365	<	String up = System.getProperty(propPrefix + "exceptionHandler");
3366	<	int par;
3367	<	if ((pp == null \|\| (par = Integer.parseInt(pp)) <= 0))
3368	<	par = Runtime.getRuntime().availableProcessors();
3369	<	commonPoolParallelism = par;
3361	>	submitters = new ThreadLocal<Submitter>();
3362	>	ForkJoinWorkerThreadFactory fac = defaultForkJoinWorkerThreadFactory =
3363	>	new DefaultForkJoinWorkerThreadFactory();
3364	>	modifyThreadPermission = new RuntimePermission("modifyThread");
3365	>
3366	>	/*
3367	>	* Establish common pool parameters. For extra caution,
3368	>	* computations to set up common pool state are here; the
3369	>	* constructor just assigns these values to fields.
3370	>	*/
3371	>
3372	>	int par = 0;
3373	>	Thread.UncaughtExceptionHandler handler = null;
3374	>	try { // TBD: limit or report ignored exceptions?
3375	>	String pp = System.getProperty
3376	>	("java.util.concurrent.ForkJoinPool.common.parallelism");
3377	>	String hp = System.getProperty
3378	>	("java.util.concurrent.ForkJoinPool.common.exceptionHandler");
3379	>	String fp = System.getProperty
3380	>	("java.util.concurrent.ForkJoinPool.common.threadFactory");
3381		if (fp != null)
3382	<	commonPoolFactory = (ForkJoinWorkerThreadFactory)
3383	<	ClassLoader.getSystemClassLoader().loadClass(fp).newInstance();
3384	<	else
3385	<	commonPoolFactory = defaultForkJoinWorkerThreadFactory;
3386	<	if (up != null)
3387	<	commonPoolUEH = (Thread.UncaughtExceptionHandler)
3388	<	ClassLoader.getSystemClassLoader().loadClass(up).newInstance();
3389	<	else
3390	<	commonPoolUEH = null;
3391	<	} catch (Exception e) {
3392	<	throw new Error(e);
3393	<	}
3382	>	fac = ((ForkJoinWorkerThreadFactory)ClassLoader.
3383	>	getSystemClassLoader().loadClass(fp).newInstance());
3384	>	if (hp != null)
3385	>	handler = ((Thread.UncaughtExceptionHandler)ClassLoader.
3386	>	getSystemClassLoader().loadClass(hp).newInstance());
3387	>	if (pp != null)
3388	>	par = Integer.parseInt(pp);
3389	>	} catch (Exception ignore) {
3390	>	}
3391	>
3392	>	if (par <= 0)
3393	>	par = Runtime.getRuntime().availableProcessors();
3394	>	if (par > MAX_CAP)
3395	>	par = MAX_CAP;
3396	>	commonParallelism = par;
3397	>	long np = (long)(-par); // precompute initial ctl value
3398	>	long ct = ((np << AC_SHIFT) & AC_MASK) \| ((np << TC_SHIFT) & TC_MASK);
3399	>
3400	>	common = new ForkJoinPool(par, ct, fac, handler);
3401		}
3402
3403		/**
#	Line 3033 \| Line 3410 \| public class ForkJoinPool extends Abstra
3410		private static sun.misc.Unsafe getUnsafe() {
3411		try {
3412		return sun.misc.Unsafe.getUnsafe();
3413	<	} catch (SecurityException se) {
3414	<	try {
3415	<	return java.security.AccessController.doPrivileged
3416	<	(new java.security
3417	<	.PrivilegedExceptionAction<sun.misc.Unsafe>() {
3418	<	public sun.misc.Unsafe run() throws Exception {
3419	<	java.lang.reflect.Field f = sun.misc
3420	<	.Unsafe.class.getDeclaredField("theUnsafe");
3421	<	f.setAccessible(true);
3422	<	return (sun.misc.Unsafe) f.get(null);
3423	<	}});
3424	<	} catch (java.security.PrivilegedActionException e) {
3425	<	throw new RuntimeException("Could not initialize intrinsics",
3426	<	e.getCause());
3427	<	}
3413	>	} catch (SecurityException tryReflectionInstead) {}
3414	>	try {
3415	>	return java.security.AccessController.doPrivileged
3416	>	(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
3417	>	public sun.misc.Unsafe run() throws Exception {
3418	>	Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class;
3419	>	for (java.lang.reflect.Field f : k.getDeclaredFields()) {
3420	>	f.setAccessible(true);
3421	>	Object x = f.get(null);
3422	>	if (k.isInstance(x))
3423	>	return k.cast(x);
3424	>	}
3425	>	throw new NoSuchFieldError("the Unsafe");
3426	>	}});
3427	>	} catch (java.security.PrivilegedActionException e) {
3428	>	throw new RuntimeException("Could not initialize intrinsics",
3429	>	e.getCause());
3430		}
3431		}
3053	–
3432		}

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Comparing jsr166/src/jsr166e/ForkJoinPool.java (file contents): Revision 1.7 by dl, Sun Oct 28 22:35:45 2012 UTC vs. Revision 1.45 by jsr166, Wed Jan 9 02:51:36 2013 UTC

Diff Legend

Comparing jsr166/src/jsr166e/ForkJoinPool.java (file contents):
Revision 1.7 by dl, Sun Oct 28 22:35:45 2012 UTC vs.
Revision 1.45 by jsr166, Wed Jan 9 02:51:36 2013 UTC