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root/jsr166/jsr166/src/jsr166y/ForkJoinPool.java

Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.146 by dl, Mon Nov 19 18:12:42 2012 UTC vs.
Revision 1.164 by dl, Tue Dec 18 21:46:16 2012 UTC

#	Line 51 | Line 51 | import java.util.concurrent.TimeUnit;
51		* dynamically adding, suspending, or resuming internal worker
52		* threads, even if some tasks are stalled waiting to join
53		* others. However, no such adjustments are guaranteed in the face of
54	<	* blocked IO or other unmanaged synchronization. The nested {@link
54	>	* blocked I/O or other unmanaged synchronization. The nested {@link
55		* ManagedBlocker} interface enables extension of the kinds of
56		* synchronization accommodated.
57		*
#	Line 99 | Line 99 | import java.util.concurrent.TimeUnit;
99		*
100		* <p>The common pool is by default constructed with default
101		* parameters, but these may be controlled by setting three {@link
102	<	* System#getProperty properties} with prefix {@code
102	>	* System#getProperty system properties} with prefix {@code
103		* java.util.concurrent.ForkJoinPool.common}: {@code parallelism} --
104		* an integer greater than zero, {@code threadFactory} -- the class
105		* name of a {@link ForkJoinWorkerThreadFactory}, and {@code
106	–	<<<<<<< ForkJoinPool.java
107	–	* exceptionHandler} -- the class name of a {@code
108	–	=======
106		* exceptionHandler} -- the class name of a {@link
107		* java.lang.Thread.UncaughtExceptionHandler
111	–	>>>>>>> 1.111
108		* Thread.UncaughtExceptionHandler}. Upon any error in establishing
109		* these settings, default parameters are used.
110		*
#	Line 320 | Line 316 | public class ForkJoinPool extends Abstra
316		* execute. However, many other threads may notice the same task
317		* and each signal to wake up a thread that might take it. So in
318		* general, pools will be over-signalled.  When a submission is
319	<	* added or another worker adds a task to a queue that is
320	<	* apparently empty, they signal waiting workers (or trigger
321	<	* creation of new ones if fewer than the given parallelism
322	<	* level).  These primary signals are buttressed by signals
323	<	* whenever other threads scan for work or do not have a task to
324	<	* process (including the case of leaving a hint to unparked
325	<	* threads to help signal others upon wakeup).  On most platforms,
326	<	* signalling (unpark) overhead time is noticeably long, and the
327	<	* time between signalling a thread and it actually making
328	<	* progress can be very noticeably long, so it is worth offloading
329	<	* these delays from critical paths as much as possible.
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 538 | Line 535 | public class ForkJoinPool extends Abstra
535		}
536
537		/**
538	+	* Per-thread records for threads that submit to pools. Currently
539	+	* holds only pseudo-random seed / index that is used to choose
540	+	* submission queues in method externalPush. In the future, this may
541	+	* also incorporate a means to implement different task rejection
542	+	* and resubmission policies.
543	+	*
544	+	* Seeds for submitters and workers/workQueues work in basically
545	+	* the same way but are initialized and updated using slightly
546	+	* different mechanics. Both are initialized using the same
547	+	* approach as in class ThreadLocal, where successive values are
548	+	* unlikely to collide with previous values. Seeds are then
549	+	* randomly modified upon collisions using xorshifts, which
550	+	* requires a non-zero seed.
551	+	*/
552	+	static final class Submitter {
553	+	int seed;
554	+	Submitter(int s) { seed = s; }
555	+	}
556	+
557	+	/**
558		* Class for artificial tasks that are used to replace the target
559		* of local joins if they are removed from an interior queue slot
560		* in WorkQueue.tryRemoveAndExec. We don't need the proxy to
#	Line 603 | 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.)
623	>	* properties of JVM field layout rules.) We also take care in
624	>	* allocating, sizing and resizing the array. Non-shared queue
625	>	* arrays are initialized by workers before use. Others are
626	>	* allocated on first use.
627		*/
628		static final class WorkQueue {
629		/**
#	Line 626 | Line 646 | public class ForkJoinPool extends Abstra
646		*/
647		static final int MAXIMUM_QUEUE_CAPACITY = 1 << 26; // 64M
648
649	+	// Heuristic padding to ameliorate unfortunate memory placements
650	+	volatile long pad00, pad01, pad02, pad03, pad04, pad05, pad06;
651	+
652		int seed;                  // for random scanning; initialize nonzero
653		volatile int eventCount;   // encoded inactivation count; < 0 if inactive
654		int nextWait;              // encoded record of next event waiter
#	Line 643 | Line 666 | public class ForkJoinPool extends Abstra
666		volatile ForkJoinTask<?> currentJoin;  // task being joined in awaitJoin
667		ForkJoinTask<?> currentSteal; // current non-local task being executed
668
669	<	// Heuristic padding to ameliorate unfortunate memory placements
670	<	Object p00, p01, p02, p03, p04, p05, p06, p07;
648	<	Object p08, p09, p0a, p0b, p0c;
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) {
652	–	this.array = new ForkJoinTask<?>[WorkQueue.INITIAL_QUEUE_CAPACITY];
674		this.pool = pool;
675		this.owner = owner;
676		this.mode = mode;
677		this.seed = seed;
678	<	// Place indices in the center of array
678	>	// Place indices in the center of array (that is not yet allocated)
679		base = top = INITIAL_QUEUE_CAPACITY >>> 1;
680		}
681
682		/**
683	<	* Pushes a task. Call only by owner in unshared queues.
684	<	* Cases needing resizing or rejection are relayed to fullPush
685	<	* (that also handles shared queues).
683	>	* Returns the approximate number of tasks in the queue.
684	>	*/
685	>	final int queueSize() {
686	>	int n = base - top;       // non-owner callers must read base first
687	>	return (n >= 0) ? 0 : -n; // ignore transient negative
688	>	}
689	>
690	>	/**
691	>	* Provides a more accurate estimate of whether this queue has
692	>	* any tasks than does queueSize, by checking whether a
693	>	* near-empty queue has at least one unclaimed task.
694	>	*/
695	>	final boolean isEmpty() {
696	>	ForkJoinTask<?>[] a; int m, s;
697	>	int n = base - (s = top);
698	>	return (n >= 0 ||
699	>	(n == -1 &&
700	>	((a = array) == null ||
701	>	(m = a.length - 1) < 0 ||
702	>	U.getObject
703	>	(a, (long)((m & (s - 1)) << ASHIFT) + ABASE) == null)));
704	>	}
705	>
706	>	/**
707	>	* Pushes a task. 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 670 | 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);
719	<	if ((n = (top = s + 1) - base) <= 1) {
717	>	int j = (((m = a.length - 1) & s) << ASHIFT) + ABASE;
718	>	U.putOrderedObject(a, j, task);
719	>	if ((n = (top = s + 1) - base) <= 2) {
720		if ((p = pool) != null)
721	<	p.signalWork(this, 0);
721	>	p.signalWork(this);
722		}
723		else if (n >= m)
724		growArray();
725		}
726		}
727
684	–	/**
685	–	* Pushes a task if lock is free and array is either big
686	–	* enough or can be resized to be big enough.
687	–	*
688	–	* @param task the task. Caller must ensure non-null.
689	–	* @return true if submitted
690	–	*/
691	–	final boolean trySharedPush(ForkJoinTask<?> task) {
692	–	boolean submitted = false;
693	–	if (qlock == 0 && U.compareAndSwapInt(this, QLOCK, 0, 1)) {
694	–	ForkJoinTask<?>[] a = array;  ForkJoinPool p;
695	–	int s = top;
696	–	try {
697	–	if ((a != null && a.length > s + 1 - base) ||
698	–	(a = growArray()) != null) {   // must presize
699	–	int j = (((a.length - 1) & s) << ASHIFT) + ABASE;
700	–	U.putOrderedObject(a, j, task);
701	–	top = s + 1;
702	–	submitted = true;
703	–	}
704	–	} finally {
705	–	qlock = 0;                         // unlock
706	–	}
707	–	if (submitted && (p = pool) != null)
708	–	p.signalWork(this, 0);
709	–	}
710	–	return submitted;
711	–	}
712	–
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
#	Line 859 | Line 874 | public class ForkJoinPool extends Abstra
874		return seed = r ^= r << 5;
875		}
876
862	–	/**
863	–	* Provides a more accurate estimate of size than (top - base)
864	–	* by ordering reads and checking whether a near-empty queue
865	–	* has at least one unclaimed task.
866	–	*/
867	–	final int queueSize() {
868	–	ForkJoinTask<?>[] a; int k, s, n;
869	–	return ((n = base - (s = top)) < 0 &&
870	–	(n != -1 ||
871	–	((a = array) != null && (k = a.length) > 0 &&
872	–	U.getObject
873	–	(a, (long)((((k - 1) & (s - 1)) << ASHIFT) + ABASE)) != null))) ?
874	–	-n : 0;
875	–	}
876	–
877		// Specialized execution methods
878
879		/**
#	Line 988 | Line 988 | public class ForkJoinPool extends Abstra
988		(currentSteal = t).doExec();
989		currentSteal = null;
990		++nsteals;
991	<	if (top != base) {       // process remaining local tasks
991	>	if (base - top < 0) {       // process remaining local tasks
992		if (mode == 0)
993		popAndExecAll();
994		else
#	Line 1020 | Line 1020 | public class ForkJoinPool extends Abstra
1020		s != Thread.State.TIMED_WAITING);
1021		}
1022
1023	–	/**
1024	–	* If this owned and is not already interrupted, try to
1025	–	* interrupt and/or unpark, ignoring exceptions.
1026	–	*/
1027	–	final void interruptOwner() {
1028	–	Thread wt, p;
1029	–	if ((wt = owner) != null && !wt.isInterrupted()) {
1030	–	try {
1031	–	wt.interrupt();
1032	–	} catch (SecurityException ignore) {
1033	–	}
1034	–	}
1035	–	if ((p = parker) != null)
1036	–	U.unpark(p);
1037	–	}
1038	–
1023		// Unsafe mechanics
1024		private static final sun.misc.Unsafe U;
1025		private static final long QLOCK;
#	Line 1070 | Line 1054 | public class ForkJoinPool extends Abstra
1054		defaultForkJoinWorkerThreadFactory;
1055
1056		/**
1073	–	* Per-thread records for threads that submit to pools. Currently
1074	–	* holds only pseudo-random seed / index that is used to choose
1075	–	* submission queues in method externalPush. In the future, this may
1076	–	* also incorporate a means to implement different task rejection
1077	–	* and resubmission policies.
1078	–	*
1079	–	* Seeds for submitters and workers/workQueues work in basically
1080	–	* the same way but are initialized and updated using slightly
1081	–	* different mechanics. Both are initialized using the same
1082	–	* approach as in class ThreadLocal, where successive values are
1083	–	* unlikely to collide with previous values. Seeds are then
1084	–	* randomly modified upon collisions using xorshifts, which
1085	–	* requires a non-zero seed.
1086	–	*/
1087	–	static final class Submitter {
1088	–	int seed;
1089	–	Submitter(int s) { seed = s; }
1090	–	}
1091	–
1092	–	/**
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.
#	Line 1099 | Line 1063 | public class ForkJoinPool extends Abstra
1063		static final ThreadLocal<Submitter> submitters;
1064
1065		/**
1066	+	* Permission required for callers of methods that may start or
1067	+	* kill threads.
1068	+	*/
1069	+	private static final RuntimePermission modifyThreadPermission;
1070	+
1071	+	/**
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
#	Line 1107 | Line 1077 | public class ForkJoinPool extends Abstra
1077		static final ForkJoinPool commonPool;
1078
1079		/**
1110	–	* Permission required for callers of methods that may start or
1111	–	* kill threads.
1112	–	*/
1113	–	private static final RuntimePermission modifyThreadPermission;
1114	–
1115	–	/**
1080		* Common pool parallelism. Must equal commonPool.parallelism.
1081		*/
1082		static final int commonPoolParallelism;
#	Line 1148 | Line 1112 | public class ForkJoinPool extends Abstra
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.  Depths for legitimate
1122		* chains are unbounded, but we use a fixed constant to avoid
#	Line 1259 | Line 1228 | public class ForkJoinPool extends Abstra
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		volatile int plock;                        // shutdown status and seqLock
#	Line 1269 | Line 1242 | public class ForkJoinPool extends Abstra
1242		final Thread.UncaughtExceptionHandler ueh; // per-worker UEH
1243		final String workerNamePrefix;             // to create worker name string
1244
1245	+	volatile Object pad10, pad11, pad12, pad13, pad14, pad15, pad16, pad17;
1246	+	volatile Object pad18, pad19, pad1a, pad1b;
1247	+
1248		/*
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.  See
1279	<	* internal ConcurrentHashMap documentation for further
1280	<	* explanation of nearly the same construction.
1254	>	* a more conservative alternative to a pure spinlock.
1255		*/
1256		private int acquirePlock() {
1257		int spins = PL_SPINS, r = 0, ps, nps;
#	Line 1329 | Line 1303 | public class ForkJoinPool extends Abstra
1303		}
1304
1305		/**
1332	–	* Tries to create and start a worker; adjusts counts etc on failure
1333	–	*/
1334	–	private void addWorker() {
1335	–	ForkJoinWorkerThread wt = null;
1336	–	try {
1337	–	(wt = factory.newThread(this)).start();
1338	–	} catch (Throwable ex) {
1339	–	deregisterWorker(wt, ex); // adjust on failure
1340	–	}
1341	–	}
1342	–
1343	–	/**
1306		* Performs secondary initialization, called when plock is zero.
1307		* Creates workQueue array and sets plock to a valid value.  The
1308		* lock body must be exception-free (so no try/finally) so we
#	Line 1349 | Line 1311 | public class ForkJoinPool extends Abstra
1311		* fullExternalPush.)  Because the plock seq value can eventually
1312		* wrap around zero, this method harmlessly fails to reinitialize
1313		* if workQueues exists, while still advancing plock.
1314	+	*
1315	+	* Additionally tries to create the first worker.
1316		*/
1317	<	private void initWorkQueuesArray() {
1318	<	WorkQueue[] ws; int ps;
1317	>	private void initWorkers() {
1318	>	WorkQueue[] ws, nws; int ps;
1319		int p = config & SMASK;        // find power of two table size
1320		int n = (p > 1) ? p - 1 : 1;   // ensure at least 2 slots
1321		n |= n >>> 1; n |= n >>> 2; n |= n >>> 4; n |= n >>> 8; n |= n >>> 16;
1322	<	WorkQueue[] nws = new WorkQueue[(n + 1) << 1];
1322	>	n = (n + 1) << 1;
1323	>	if ((ws = workQueues) == null || ws.length == 0)
1324	>	nws = new WorkQueue[n];
1325	>	else
1326	>	nws = null;
1327		if (((ps = plock) & PL_LOCK) != 0 ||
1328		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1329		ps = acquirePlock();
1330	<	if ((ws = workQueues) == null || ws.length == 0)
1330	>	if (((ws = workQueues) == null || ws.length == 0) && nws != null)
1331		workQueues = nws;
1332		int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1333		if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1334		releasePlock(nps);
1335	+	tryAddWorker();
1336	+	}
1337	+
1338	+	/**
1339	+	* Tries to create and start one worker if fewer than target
1340	+	* parallelism level exist. Adjusts counts etc on failure.
1341	+	*/
1342	+	private void tryAddWorker() {
1343		long c; int u;
1344	<	if ((u = (int)((c = ctl) >>> 32)) < 0 && (int)c == 0) {
1344	>	while ((u = (int)((c = ctl) >>> 32)) < 0 &&
1345	>	(u & SHORT_SIGN) != 0 && (int)c == 0) {
1346		long nc = (long)(((u + UTC_UNIT) & UTC_MASK) |
1347		((u + UAC_UNIT) & UAC_MASK)) << 32;
1348	<	if (U.compareAndSwapLong(this, CTL, c, nc))
1349	<	addWorker();
1348	>	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1349	>	ForkJoinWorkerThreadFactory fac;
1350	>	Throwable ex = null;
1351	>	ForkJoinWorkerThread wt = null;
1352	>	try {
1353	>	if ((fac = factory) != null &&
1354	>	(wt = fac.newThread(this)) != null) {
1355	>	wt.start();
1356	>	break;
1357	>	}
1358	>	} catch (Throwable e) {
1359	>	ex = e;
1360	>	}
1361	>	deregisterWorker(wt, ex);
1362	>	break;
1363	>	}
1364		}
1374	–
1365		}
1366
1367		//  Registering and deregistering workers
#	Line 1384 | Line 1374 | public class ForkJoinPool extends Abstra
1374		* expanding as needed.
1375		*
1376		* @param wt the worker thread
1377	+	* @return the worker's queue
1378		*/
1379	<	final void registerWorker(ForkJoinWorkerThread wt) {
1380	<	if (wt != null && wt.workQueue == null) {
1381	<	int s, ps;    // generate a rarely colliding candidate index seed
1382	<	do {} while (!U.compareAndSwapInt(this, INDEXSEED, s = indexSeed,
1383	<	s += SEED_INCREMENT) ||
1384	<	s == 0); // skip 0
1385	<	WorkQueue w = new WorkQueue(this, wt, config >>> 16, s);
1386	<	if (((ps = plock) & PL_LOCK) != 0 ||
1387	<	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1388	<	ps = acquirePlock();
1389	<	int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1390	<	try {
1391	<	WorkQueue[] ws;
1392	<	if ((ws = workQueues) != null && wt.workQueue == null) {
1393	<	int n = ws.length, m = n - 1;
1394	<	int r = (s << 1) | 1;           // use odd-numbered indices
1395	<	if (ws[r &= m] != null) {       // collision
1396	<	int probes = 0;             // step by approx half size
1397	<	int step = (n <= 4) ? 2 : ((n >>> 1) & EVENMASK) + 2;
1398	<	while (ws[r = (r + step) & m] != null) {
1399	<	if (++probes >= n) {
1400	<	workQueues = ws = Arrays.copyOf(ws, n <<= 1);
1401	<	m = n - 1;
1402	<	probes = 0;
1403	<	}
1379	>	final WorkQueue registerWorker(ForkJoinWorkerThread wt) {
1380	>	Thread.UncaughtExceptionHandler handler; WorkQueue[] ws; int s, ps;
1381	>	wt.setDaemon(true);
1382	>	if ((handler = ueh) != null)
1383	>	wt.setUncaughtExceptionHandler(handler);
1384	>	do {} while (!U.compareAndSwapInt(this, INDEXSEED, s = indexSeed,
1385	>	s += SEED_INCREMENT) ||
1386	>	s == 0); // skip 0
1387	>	WorkQueue w = new WorkQueue(this, wt, config >>> 16, s);
1388	>	if (((ps = plock) & PL_LOCK) != 0 ||
1389	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1390	>	ps = acquirePlock();
1391	>	int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1392	>	try {
1393	>	if ((ws = workQueues) != null) {    // skip if shutting down
1394	>	int n = ws.length, m = n - 1;
1395	>	int r = (s << 1) | 1;           // use odd-numbered indices
1396	>	if (ws[r &= m] != null) {       // collision
1397	>	int probes = 0;             // step by approx half size
1398	>	int step = (n <= 4) ? 2 : ((n >>> 1) & EVENMASK) + 2;
1399	>	while (ws[r = (r + step) & m] != null) {
1400	>	if (++probes >= n) {
1401	>	workQueues = ws = Arrays.copyOf(ws, n <<= 1);
1402	>	m = n - 1;
1403	>	probes = 0;
1404		}
1405		}
1415	–	w.eventCount = w.poolIndex = r; // volatile write orders
1416	–	wt.workQueue = ws[r] = w;
1406		}
1407	<	} finally {
1408	<	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1420	<	releasePlock(nps);
1407	>	w.eventCount = w.poolIndex = r; // volatile write orders
1408	>	ws[r] = w;
1409		}
1410	+	} finally {
1411	+	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1412	+	releasePlock(nps);
1413		}
1414	+	wt.setName(workerNamePrefix.concat(Integer.toString(w.poolIndex)));
1415	+	return w;
1416		}
1417
1418		/**
#	Line 1454 | Line 1447 | public class ForkJoinPool extends Abstra
1447		}
1448		}
1449
1450	<	long c;                             // adjust ctl counts
1450	>	long c;                          // adjust ctl counts
1451		do {} while (!U.compareAndSwapLong
1452		(this, CTL, c = ctl, (((c - AC_UNIT) & AC_MASK) |
1453		((c - TC_UNIT) & TC_MASK) |
1454		(c & ~(AC_MASK|TC_MASK)))));
1455
1456	<	if (!tryTerminate(false, false) && w != null) {
1457	<	w.cancelAll();                  // cancel remaining tasks
1458	<	if (w.array != null)            // suppress signal if never ran
1459	<	helpSignal(null, 0);        // wake up or create replacement
1460	<	if (ex == null)                 // help clean refs on way out
1461	<	ForkJoinTask.helpExpungeStaleExceptions();
1456	>	if (!tryTerminate(false, false) && w != null && w.array != null) {
1457	>	w.cancelAll();               // cancel remaining tasks
1458	>	WorkQueue[] ws; WorkQueue v; Thread p; int u, i, e;
1459	>	while ((u = (int)((c = ctl) >>> 32)) < 0 && (e = (int)c) >= 0) {
1460	>	if (e > 0) {             // activate or create replacement
1461	>	if ((ws = workQueues) == null ||
1462	>	(i = e & SMASK) >= ws.length ||
1463	>	(v = ws[i]) == null)
1464	>	break;
1465	>	long nc = (((long)(v.nextWait & E_MASK)) |
1466	>	((long)(u + UAC_UNIT) << 32));
1467	>	if (v.eventCount != (e | INT_SIGN))
1468	>	break;
1469	>	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1470	>	v.eventCount = (e + E_SEQ) & E_MASK;
1471	>	if ((p = v.parker) != null)
1472	>	U.unpark(p);
1473	>	break;
1474	>	}
1475	>	}
1476	>	else {
1477	>	if ((short)u < 0)
1478	>	tryAddWorker();
1479	>	break;
1480	>	}
1481	>	}
1482		}
1483	<
1484	<	if (ex != null)                     // rethrow
1483	>	if (ex == null)                     // help clean refs on way out
1484	>	ForkJoinTask.helpExpungeStaleExceptions();
1485	>	else                                // rethrow
1486		ForkJoinTask.rethrow(ex);
1487		}
1488
#	Line 1490 | Line 1504 | public class ForkJoinPool extends Abstra
1504		U.compareAndSwapInt(q, QLOCK, 0, 1)) { // lock
1505		int b = q.base, s = q.top, n, an;
1506		if ((a = q.array) != null && (an = a.length) > (n = s + 1 - b)) {
1507	<	U.putObject(a, (long)(((an - 1) & s) << ASHIFT) + ABASE, task);
1507	>	int j = (((an - 1) & s) << ASHIFT) + ABASE;
1508	>	U.putOrderedObject(a, j, task);
1509		q.top = s + 1;                     // push on to deque
1510		q.qlock = 0;
1511		if (n <= 2)
1512	<	signalWork(q, 0);
1512	>	signalWork(q);
1513		return;
1514		}
1515		q.qlock = 0;
#	Line 1506 | Line 1521 | public class ForkJoinPool extends Abstra
1521		* Full version of externalPush. This method is called, among
1522		* other times, upon the first submission of the first task to the
1523		* pool, so must perform secondary initialization (via
1524	<	* initWorkQueuesArray). It also detects first submission by an
1525	<	* external thread by looking up its ThreadLocal, and creates a
1526	<	* new shared queue if the one at index if empty or contended. The
1527	<	* lock body must be exception-free (so no try/finally) so we
1524	>	* initWorkers). It also detects first submission by an external
1525	>	* thread by looking up its ThreadLocal, and creates a new shared
1526	>	* queue if the one at index if empty or contended. The plock lock
1527	>	* body must be exception-free (so no try/finally) so we
1528		* optimistically allocate new queues outside the lock and throw
1529		* them away if (very rarely) not needed.
1530		*/
1531		private void fullExternalPush(ForkJoinTask<?> task) {
1532	<	int r = 0;
1532	>	int r = 0; // random index seed
1533		for (Submitter z = submitters.get();;) {
1534		WorkQueue[] ws; WorkQueue q; int ps, m, k;
1535		if (z == null) {
#	Line 1532 | Line 1547 | public class ForkJoinPool extends Abstra
1547		throw new RejectedExecutionException();
1548		else if (ps == 0 || (ws = workQueues) == null ||
1549		(m = ws.length - 1) < 0)
1550	<	initWorkQueuesArray();
1550	>	initWorkers();
1551		else if ((q = ws[k = r & m & SQMASK]) != null) {
1552	<	if (q.trySharedPush(task))
1553	<	return;
1554	<	else
1555	<	r = 0; // move on contention
1552	>	if (q.qlock == 0 && U.compareAndSwapInt(q, QLOCK, 0, 1)) {
1553	>	ForkJoinTask<?>[] a = q.array;
1554	>	int s = q.top;
1555	>	boolean submitted = false;
1556	>	try {                      // locked version of push
1557	>	if ((a != null && a.length > s + 1 - q.base) ||
1558	>	(a = q.growArray()) != null) {   // must presize
1559	>	int j = (((a.length - 1) & s) << ASHIFT) + ABASE;
1560	>	U.putOrderedObject(a, j, task);
1561	>	q.top = s + 1;
1562	>	submitted = true;
1563	>	}
1564	>	} finally {
1565	>	q.qlock = 0;  // unlock
1566	>	}
1567	>	if (submitted) {
1568	>	signalWork(q);
1569	>	return;
1570	>	}
1571	>	}
1572	>	r = 0; // move on failure
1573		}
1574		else if (((ps = plock) & PL_LOCK) == 0) { // create new queue
1575		q = new WorkQueue(this, null, SHARED_QUEUE, r);
#	Line 1566 | Line 1598 | public class ForkJoinPool extends Abstra
1598		}
1599
1600		/**
1601	<	* Tries to create (at most one) or activate (possibly several)
1602	<	* workers if too few are active. On contention failure, continues
1603	<	* until at least one worker is signalled or the given queue is
1572	<	* empty or all workers are active.
1573	<	*
1574	<	* @param q if non-null, the queue holding tasks to be signalled
1575	<	* @param signals the target number of signals (at least one --
1576	<	* if argument is zero also sets signallee hint if parked).
1601	>	* Tries to create or activate a worker if too few are active.
1602	>	*
1603	>	* @param q the (non-null) queue holding tasks to be signalled
1604		*/
1605	<	final void signalWork(WorkQueue q, int signals) {
1606	<	long c; int e, u, i, s; WorkQueue[] ws; WorkQueue w; Thread p;
1605	>	final void signalWork(WorkQueue q) {
1606	>	int hint = q.poolIndex;
1607	>	long c; int e, u, i, n; WorkQueue[] ws; WorkQueue w; Thread p;
1608		while ((u = (int)((c = ctl) >>> 32)) < 0) {
1609		if ((e = (int)c) > 0) {
1610		if ((ws = workQueues) != null && ws.length > (i = e & SMASK) &&
#	Line 1584 | Line 1612 | public class ForkJoinPool extends Abstra
1612		long nc = (((long)(w.nextWait & E_MASK)) |
1613		((long)(u + UAC_UNIT) << 32));
1614		if (U.compareAndSwapLong(this, CTL, c, nc)) {
1615	+	w.hint = hint;
1616		w.eventCount = (e + E_SEQ) & E_MASK;
1617	<	if ((p = w.parker) != null) {
1589	<	if (q != null && signals == 0)
1590	<	w.hint = q.poolIndex;
1617	>	if ((p = w.parker) != null)
1618		U.unpark(p);
1619	<	}
1593	<	if (--signals <= 0)
1594	<	break;
1619	>	break;
1620		}
1621	<	if (q != null && (s = q.queueSize()) <= signals &&
1597	<	(signals = s) <= 0)
1621	>	if (q.top - q.base <= 0)
1622		break;
1623		}
1624		else
1625		break;
1626		}
1627	<	else if (e == 0 && (u & SHORT_SIGN) != 0) {
1628	<	long nc = (long)(((u + UTC_UNIT) & UTC_MASK) |
1629	<	((u + UAC_UNIT) & UAC_MASK)) << 32;
1606	<	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1607	<	addWorker();
1608	<	break;
1609	<	}
1610	<	}
1611	<	else
1627	>	else {
1628	>	if ((short)u < 0)
1629	>	tryAddWorker();
1630		break;
1631	+	}
1632		}
1633		}
1634
#	Line 1619 | Line 1638 | public class ForkJoinPool extends Abstra
1638		* Top-level runloop for workers, called by ForkJoinWorkerThread.run.
1639		*/
1640		final void runWorker(WorkQueue w) {
1641	<	if (w != null) // skip on initialization failure
1642	<	do { w.runTask(scan(w)); } while (w.qlock >= 0);
1641	>	w.growArray(); // allocate queue
1642	>	do { w.runTask(scan(w)); } while (w.qlock >= 0);
1643		}
1644
1645		/**
#	Line 1648 | Line 1667 | public class ForkJoinPool extends Abstra
1667		*
1668		* * If not already enqueued, try to inactivate and enqueue the
1669		* worker on wait queue. Or, if inactivating has caused the pool
1670	<	* to be quiescent, relay to idleAwaitWork to check for
1671	<	* termination and possibly shrink pool.
1670	>	* to be quiescent, relay to idleAwaitWork to possibly shrink
1671	>	* pool.
1672		*
1673		* * If already enqueued and none of the above apply, possibly
1674	<	* (with 1/2 probability) park awaiting signal, else lingering to
1675	<	* help scan and signal.
1674	>	* park awaiting signal, else lingering to help scan and signal.
1675	>	*
1676	>	* * If a non-empty queue discovered or left as a hint,
1677	>	* help wake up other workers before return
1678		*
1679		* @param w the worker (via its WorkQueue)
1680		* @return a task or null if none found
1681		*/
1682		private final ForkJoinTask<?> scan(WorkQueue w) {
1683	<	WorkQueue[] ws; int m, hint;
1683	>	WorkQueue[] ws; int m;
1684		int ps = plock;                          // read plock before ws
1685		if (w != null && (ws = workQueues) != null && (m = ws.length - 1) >= 0) {
1686		int ec = w.eventCount;               // ec is negative if inactive
1687		int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
1688	<	for (int j = ((m + m + 1) | MIN_SCAN) & MAX_SCAN; ; --j) {
1688	>	w.hint = -1;                         // update seed and clear hint
1689	>	int j = ((m + m + 1) | MIN_SCAN) & MAX_SCAN;
1690	>	do {
1691		WorkQueue q; ForkJoinTask<?>[] a; int b;
1692		if ((q = ws[(r + j) & m]) != null && (b = q.base) - q.top < 0 &&
1693		(a = q.array) != null) {     // probably nonempty
#	Line 1674 | Line 1697 | public class ForkJoinPool extends Abstra
1697		if (q.base == b && ec >= 0 && t != null &&
1698		U.compareAndSwapObject(a, i, t, null)) {
1699		if ((q.base = b + 1) - q.top < 0)
1700	<	signalWork(q, 0);
1700	>	signalWork(q);
1701		return t;                // taken
1702		}
1703	<	else if (ec < 0 || j < m) {  // cannot take or cannot rescan
1704	<	w.hint = q.poolIndex;    // use hint below
1705	<	break;                   // let caller retry after signal
1706	<	}
1707	<	}
1708	<	else if (j < 0) { // end of scan; in loop to simplify code
1709	<	long c, sc; int e, ns;
1710	<	if ((ns = w.nsteals) != 0) {
1711	<	if (U.compareAndSwapLong(this, STEALCOUNT,
1712	<	sc = stealCount, sc + ns))
1713	<	w.nsteals = 0;       // collect steals
1714	<	}
1715	<	else if (plock != ps)        // ws may have changed
1716	<	break;
1717	<	else if ((e = (int)(c = ctl)) < 0)
1718	<	w.qlock = -1;            // pool is terminating
1719	<	else if (ec >= 0) {          // try to enqueue/inactivate
1720	<	long nc = ((long)ec |
1721	<	((c - AC_UNIT) & (AC_MASK|TC_MASK)));
1703	>	else if ((ec < 0 || j < m) && (int)(ctl >> AC_SHIFT) <= 0) {
1704	>	w.hint = (r + j) & m;    // help signal below
1705	>	break;                   // cannot take
1706	>	}
1707	>	}
1708	>	} while (--j >= 0);
1709	>
1710	>	int h, e, ns; long c, sc; WorkQueue q;
1711	>	if ((ns = w.nsteals) != 0) {
1712	>	if (U.compareAndSwapLong(this, STEALCOUNT,
1713	>	sc = stealCount, sc + ns))
1714	>	w.nsteals = 0;               // collect steals and rescan
1715	>	}
1716	>	else if (plock != ps)                // consistency check
1717	>	;                                // skip
1718	>	else if ((e = (int)(c = ctl)) < 0)
1719	>	w.qlock = -1;                    // pool is terminating
1720	>	else {
1721	>	if ((h = w.hint) < 0) {
1722	>	if (ec >= 0) {               // try to enqueue/inactivate
1723	>	long nc = (((long)ec |
1724	>	((c - AC_UNIT) & (AC_MASK|TC_MASK))));
1725		w.nextWait = e;          // link and mark inactive
1700	–	w.hint = -1;             // use hint if set while parked
1726		w.eventCount = ec | INT_SIGN;
1727	<	if (ctl != c ||
1728	<	!U.compareAndSwapLong(this, CTL, c, nc))
1704	<	w.eventCount = ec;  // unmark on CAS failure
1727	>	if (ctl != c || !U.compareAndSwapLong(this, CTL, c, nc))
1728	>	w.eventCount = ec;   // unmark on CAS failure
1729		else if ((int)(c >> AC_SHIFT) == 1 - (config & SMASK))
1730		idleAwaitWork(w, nc, c);
1731		}
1732	<	else if (w.eventCount < 0) { // block
1732	>	else if (w.eventCount < 0 && !tryTerminate(false, false) &&
1733	>	ctl == c) {         // block
1734		Thread wt = Thread.currentThread();
1735		Thread.interrupted();    // clear status
1736		U.putObject(wt, PARKBLOCKER, this);
#	Line 1715 | Line 1740 | public class ForkJoinPool extends Abstra
1740		w.parker = null;
1741		U.putObject(wt, PARKBLOCKER, null);
1742		}
1718	–	break;
1743		}
1744	<	}
1745	<	if ((hint = w.hint) >= 0) {          // help signal
1746	<	WorkQueue[] vs; WorkQueue v; int k;
1747	<	w.hint = -1;                     // suppress resignal
1748	<	if ((vs = workQueues) != null && hint < vs.length &&
1749	<	(v = vs[hint]) != null && (k = v.base - v.top) < -1)
1750	<	signalWork(v, 1 - k);
1744	>	if ((h >= 0 || (h = w.hint) >= 0) &&
1745	>	(ws = workQueues) != null && h < ws.length &&
1746	>	(q = ws[h]) != null) {      // signal others before retry
1747	>	WorkQueue v; Thread p; int u, i, s;
1748	>	for (int n = (config & SMASK) >>> 1;;) {
1749	>	int idleCount = (w.eventCount < 0) ? 0 : -1;
1750	>	if (((s = idleCount - q.base + q.top) <= n &&
1751	>	(n = s) <= 0) ||
1752	>	(u = (int)((c = ctl) >>> 32)) >= 0 ||
1753	>	(e = (int)c) <= 0 || m < (i = e & SMASK) ||
1754	>	(v = ws[i]) == null)
1755	>	break;
1756	>	long nc = (((long)(v.nextWait & E_MASK)) |
1757	>	((long)(u + UAC_UNIT) << 32));
1758	>	if (v.eventCount != (e | INT_SIGN) ||
1759	>	!U.compareAndSwapLong(this, CTL, c, nc))
1760	>	break;
1761	>	v.hint = h;
1762	>	v.eventCount = (e + E_SEQ) & E_MASK;
1763	>	if ((p = v.parker) != null)
1764	>	U.unpark(p);
1765	>	if (--n <= 0)
1766	>	break;
1767	>	}
1768	>	}
1769		}
1770		}
1771		return null;
#	Line 1746 | Line 1788 | public class ForkJoinPool extends Abstra
1788		!tryTerminate(false, false) && (int)prevCtl != 0) {
1789		int dc = -(short)(currentCtl >>> TC_SHIFT);
1790		long parkTime = dc < 0 ? FAST_IDLE_TIMEOUT: (dc + 1) * IDLE_TIMEOUT;
1791	<	long deadline = System.nanoTime() + parkTime - 100000L; // 1ms slop
1791	>	long deadline = System.nanoTime() + parkTime - TIMEOUT_SLOP;
1792		Thread wt = Thread.currentThread();
1793		while (ctl == currentCtl) {
1794		Thread.interrupted();  // timed variant of version in scan()
#	Line 1762 | Line 1804 | public class ForkJoinPool extends Abstra
1804		U.compareAndSwapLong(this, CTL, currentCtl, prevCtl)) {
1805		w.eventCount = (w.eventCount + E_SEQ) | E_MASK;
1806		w.qlock = -1;   // shrink
1765	–	w.hint = -1;    // suppress helping
1807		break;
1808		}
1809		}
#	Line 1770 | Line 1811 | public class ForkJoinPool extends Abstra
1811		}
1812
1813		/**
1814	<	* Scans through queues looking for work (optionally, while
1815	<	* joining a task); if any are present, signals. May return early
1816	<	* if more signalling is detectably unneeded.
1814	>	* Scans through queues looking for work while joining a task; if
1815	>	* any present, signals. May return early if more signalling is
1816	>	* detectably unneeded.
1817		*
1818	<	* @param task if non-null, return early if done
1818	>	* @param task return early if done
1819		* @param origin an index to start scan
1820		*/
1821	<	final int helpSignal(ForkJoinTask<?> task, int origin) {
1822	<	WorkQueue[] ws; WorkQueue q; int m, n, s, u;
1823	<	if ((ws = workQueues) != null && (m = ws.length - 1) >= 0) {
1824	<	for (int i = 0; i <= m; ++i) {
1825	<	if (task != null && (s = task.status) < 0)
1826	<	return s;
1827	<	if ((q = ws[(i + origin) & m]) != null &&
1828	<	(n = q.queueSize()) > 0) {
1829	<	signalWork(q, n);
1830	<	if ((u = (int)(ctl >>> 32)) >= 0 || (u >> UAC_SHIFT) >= 0)
1821	>	private void helpSignal(ForkJoinTask<?> task, int origin) {
1822	>	WorkQueue[] ws; WorkQueue w; Thread p; long c; int m, u, e, i, s;
1823	>	if (task != null && task.status >= 0 &&
1824	>	(u = (int)(ctl >>> 32)) < 0 && (u >> UAC_SHIFT) < 0 &&
1825	>	(ws = workQueues) != null && (m = ws.length - 1) >= 0) {
1826	>	outer: for (int k = origin, j = m; j >= 0; --j) {
1827	>	WorkQueue q = ws[k++ & m];
1828	>	for (int n = m;;) { // limit to at most m signals
1829	>	if (task.status < 0)
1830	>	break outer;
1831	>	if (q == null ||
1832	>	((s = -q.base + q.top) <= n && (n = s) <= 0))
1833		break;
1834	+	if ((u = (int)((c = ctl) >>> 32)) >= 0 ||
1835	+	(e = (int)c) <= 0 || m < (i = e & SMASK) ||
1836	+	(w = ws[i]) == null)
1837	+	break outer;
1838	+	long nc = (((long)(w.nextWait & E_MASK)) |
1839	+	((long)(u + UAC_UNIT) << 32));
1840	+	if (w.eventCount != (e | INT_SIGN))
1841	+	break outer;
1842	+	if (U.compareAndSwapLong(this, CTL, c, nc)) {
1843	+	w.eventCount = (e + E_SEQ) & E_MASK;
1844	+	if ((p = w.parker) != null)
1845	+	U.unpark(p);
1846	+	if (--n <= 0)
1847	+	break;
1848	+	}
1849		}
1850		}
1851		}
1794	–	return 0;
1852		}
1853
1854		/**
#	Line 1940 | Line 1997 | public class ForkJoinPool extends Abstra
1997		else if (tc + pc < MAX_CAP) {
1998		long nc = ((c + TC_UNIT) & TC_MASK) | (c & ~TC_MASK);
1999		if (U.compareAndSwapLong(this, CTL, c, nc)) {
2000	<	addWorker();
2001	<	return true;
2000	>	ForkJoinWorkerThreadFactory fac;
2001	>	Throwable ex = null;
2002	>	ForkJoinWorkerThread wt = null;
2003	>	try {
2004	>	if ((fac = factory) != null &&
2005	>	(wt = fac.newThread(this)) != null) {
2006	>	wt.start();
2007	>	return true;
2008	>	}
2009	>	} catch (Throwable rex) {
2010	>	ex = rex;
2011	>	}
2012	>	deregisterWorker(wt, ex); // clean up and return false
2013		}
2014		}
2015		}
#	Line 1960 | Line 2028 | public class ForkJoinPool extends Abstra
2028		if (joiner != null && task != null && (s = task.status) >= 0) {
2029		ForkJoinTask<?> prevJoin = joiner.currentJoin;
2030		joiner.currentJoin = task;
2031	<	do {} while ((s = task.status) >= 0 &&
1964	<	joiner.queueSize() > 0 &&
2031	>	do {} while ((s = task.status) >= 0 && !joiner.isEmpty() &&
2032		joiner.tryRemoveAndExec(task)); // process local tasks
2033	<	if (s >= 0 && (s = task.status) >= 0 &&
2034	<	(s = helpSignal(task, joiner.poolIndex)) >= 0 &&
2035	<	(task instanceof CountedCompleter))
2036	<	s = helpComplete(task, LIFO_QUEUE);
2037	<	int k = 0; // to perform pre-block yield for politeness
2033	>	if (s >= 0 && (s = task.status) >= 0) {
2034	>	helpSignal(task, joiner.poolIndex);
2035	>	if ((s = task.status) >= 0 &&
2036	>	(task instanceof CountedCompleter))
2037	>	s = helpComplete(task, LIFO_QUEUE);
2038	>	}
2039		while (s >= 0 && (s = task.status) >= 0) {
2040	<	if ((joiner.queueSize() > 0 ||           // try helping
2040	>	if ((!joiner.isEmpty() ||           // try helping
2041		(s = tryHelpStealer(joiner, task)) == 0) &&
2042		(s = task.status) >= 0) {
2043	<	if (k < 3) {
2044	<	if (++k < 3)
1977	<	s = helpSignal(task, joiner.poolIndex);
1978	<	else
1979	<	Thread.yield();
1980	<	}
1981	<	else if (!tryCompensate())
1982	<	k = 0;
1983	<	else {
2043	>	helpSignal(task, joiner.poolIndex);
2044	>	if ((s = task.status) >= 0 && tryCompensate()) {
2045		if (task.trySetSignal() && (s = task.status) >= 0) {
2046		synchronized (task) {
2047		if (task.status >= 0) {
#	Line 2017 | Line 2078 | public class ForkJoinPool extends Abstra
2078		if (joiner != null && task != null && (s = task.status) >= 0) {
2079		ForkJoinTask<?> prevJoin = joiner.currentJoin;
2080		joiner.currentJoin = task;
2081	<	do {} while ((s = task.status) >= 0 &&
2021	<	joiner.queueSize() > 0 &&
2081	>	do {} while ((s = task.status) >= 0 && !joiner.isEmpty() &&
2082		joiner.tryRemoveAndExec(task));
2083	<	if (s >= 0 && (s = task.status) >= 0 &&
2084	<	(s = helpSignal(task, joiner.poolIndex)) >= 0 &&
2085	<	(task instanceof CountedCompleter))
2086	<	s = helpComplete(task, LIFO_QUEUE);
2087	<	if (s >= 0 && joiner.queueSize() == 0) {
2083	>	if (s >= 0 && (s = task.status) >= 0) {
2084	>	helpSignal(task, joiner.poolIndex);
2085	>	if ((s = task.status) >= 0 &&
2086	>	(task instanceof CountedCompleter))
2087	>	s = helpComplete(task, LIFO_QUEUE);
2088	>	}
2089	>	if (s >= 0 && joiner.isEmpty()) {
2090		do {} while (task.status >= 0 &&
2091		tryHelpStealer(joiner, task) > 0);
2092		}
#	Line 2041 | Line 2103 | public class ForkJoinPool extends Abstra
2103		*/
2104		private WorkQueue findNonEmptyStealQueue(int r) {
2105		for (WorkQueue[] ws;;) {
2106	<	int ps = plock, m, n;
2106	>	int ps = plock, m;
2107		if ((ws = workQueues) == null || (m = ws.length - 1) < 1)
2108		return null;
2109		for (int j = (m + 1) << 2; ;) {
2110		WorkQueue q = ws[(((r + j) << 1) | 1) & m];
2111	<	if (q != null && (n = q.queueSize()) > 0) {
2050	<	if (n > 1)
2051	<	signalWork(q, 0);
2111	>	if (q != null && q.base - q.top < 0)
2112		return q;
2053	–	}
2113		else if (--j < 0) {
2114		if (plock == ps)
2115		return null;
#	Line 2081 | Line 2140 | public class ForkJoinPool extends Abstra
2140		do {} while (!U.compareAndSwapLong
2141		(this, CTL, c = ctl, c + AC_UNIT));
2142		}
2143	<	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null)
2143	>	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null) {
2144	>	if (q.base - q.top < 0)
2145	>	signalWork(q);
2146		w.runSubtask(t);
2147	+	}
2148		}
2149		else {
2150		long c;
#	Line 2114 | Line 2176 | public class ForkJoinPool extends Abstra
2176		return t;
2177		if ((q = findNonEmptyStealQueue(w.nextSeed())) == null)
2178		return null;
2179	<	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null)
2179	>	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null) {
2180	>	if (q.base - q.top < 0)
2181	>	signalWork(q);
2182		return t;
2183	+	}
2184		}
2185		}
2186
#	Line 2215 | Line 2280 | public class ForkJoinPool extends Abstra
2280		if (((ps = plock) & PL_LOCK) != 0 ||
2281		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
2282		ps = acquirePlock();
2283	<	int nps = SHUTDOWN;
2284	<	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
2220	<	releasePlock(nps);
2283	>	if (!U.compareAndSwapInt(this, PLOCK, ps, SHUTDOWN))
2284	>	releasePlock(SHUTDOWN);
2285		}
2286		if (!now) {                             // check if idle & no tasks
2287		if ((int)(c >> AC_SHIFT) != -(config & SMASK) ||
#	Line 2236 | Line 2300 | public class ForkJoinPool extends Abstra
2300		for (int pass = 0; pass < 3; ++pass) {
2301		WorkQueue[] ws = workQueues;
2302		if (ws != null) {
2303	<	WorkQueue w;
2303	>	WorkQueue w; Thread wt;
2304		int n = ws.length;
2305		for (int i = 0; i < n; ++i) {
2306		if ((w = ws[i]) != null) {
2307		w.qlock = -1;
2308		if (pass > 0) {
2309		w.cancelAll();
2310	<	if (pass > 1)
2311	<	w.interruptOwner();
2310	>	if (pass > 1 && (wt = w.owner) != null) {
2311	>	if (!wt.isInterrupted()) {
2312	>	try {
2313	>	wt.interrupt();
2314	>	} catch (SecurityException ignore) {
2315	>	}
2316	>	}
2317	>	U.unpark(wt);
2318	>	}
2319		}
2320		}
2321		}
#	Line 2290 | Line 2361 | public class ForkJoinPool extends Abstra
2361		*/
2362		static boolean tryExternalUnpush(ForkJoinTask<?> t) {
2363		ForkJoinPool p; WorkQueue[] ws; WorkQueue q; Submitter z;
2364	<	ForkJoinTask<?>[] a;  int m, s; long j;
2365	<	if ((z = submitters.get()) != null &&
2364	>	ForkJoinTask<?>[] a;  int m, s;
2365	>	if (t != null &&
2366	>	(z = submitters.get()) != null &&
2367		(p = commonPool) != null &&
2368		(ws = p.workQueues) != null &&
2369		(m = ws.length - 1) >= 0 &&
2370		(q = ws[m & z.seed & SQMASK]) != null &&
2371		(s = q.top) != q.base &&
2372	<	(a = q.array) != null &&
2373	<	U.getObjectVolatile
2374	<	(a, j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE) == t &&
2375	<	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2376	<	if (q.array == a && q.top == s && // recheck
2377	<	U.compareAndSwapObject(a, j, t, null)) {
2378	<	q.top = s - 1;
2372	>	(a = q.array) != null) {
2373	>	long j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE;
2374	>	if (U.getObject(a, j) == t &&
2375	>	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2376	>	if (q.array == a && q.top == s && // recheck
2377	>	U.compareAndSwapObject(a, j, t, null)) {
2378	>	q.top = s - 1;
2379	>	q.qlock = 0;
2380	>	return true;
2381	>	}
2382		q.qlock = 0;
2308	–	return true;
2383		}
2310	–	q.qlock = 0;
2384		}
2385		return false;
2386		}
#	Line 2349 | Line 2422 | public class ForkJoinPool extends Abstra
2422		(u = (int)(ctl >>> 32)) >= 0 || (u >> UAC_SHIFT) >= 0)
2423		break;
2424		if (task == null) {
2425	<	if (helpSignal(root, q.poolIndex) >= 0)
2425	>	helpSignal(root, q.poolIndex);
2426	>	if (root.status >= 0)
2427		helpComplete(root, SHARED_QUEUE);
2428		break;
2429		}
#	Line 2364 | Line 2438 | public class ForkJoinPool extends Abstra
2438		static void externalHelpJoin(ForkJoinTask<?> t) {
2439		// Some hard-to-avoid overlap with tryExternalUnpush
2440		ForkJoinPool p; WorkQueue[] ws; WorkQueue q, w; Submitter z;
2441	<	ForkJoinTask<?>[] a;  int m, s, n; long j;
2441	>	ForkJoinTask<?>[] a;  int m, s, n;
2442		if (t != null &&
2443		(z = submitters.get()) != null &&
2444		(p = commonPool) != null &&
2445		(ws = p.workQueues) != null &&
2446		(m = ws.length - 1) >= 0 &&
2447		(q = ws[m & z.seed & SQMASK]) != null &&
2448	<	(a = q.array) != null &&
2449	<	t.status >= 0) {
2450	<	if ((s = q.top) != q.base &&
2451	<	U.getObjectVolatile
2452	<	(a, j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE) == t &&
2453	<	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2454	<	if (q.array == a && q.top == s &&
2455	<	U.compareAndSwapObject(a, j, t, null)) {
2456	<	q.top = s - 1;
2457	<	q.qlock = 0;
2458	<	t.doExec();
2448	>	(a = q.array) != null) {
2449	>	int am = a.length - 1;
2450	>	if ((s = q.top) != q.base) {
2451	>	long j = ((am & (s - 1)) << ASHIFT) + ABASE;
2452	>	if (U.getObject(a, j) == t &&
2453	>	U.compareAndSwapInt(q, QLOCK, 0, 1)) {
2454	>	if (q.array == a && q.top == s &&
2455	>	U.compareAndSwapObject(a, j, t, null)) {
2456	>	q.top = s - 1;
2457	>	q.qlock = 0;
2458	>	t.doExec();
2459	>	}
2460	>	else
2461	>	q.qlock = 0;
2462		}
2386	–	else
2387	–	q.qlock = 0;
2463		}
2464		if (t.status >= 0) {
2465		if (t instanceof CountedCompleter)
#	Line 2403 | Line 2478 | public class ForkJoinPool extends Abstra
2478		if ((p = commonPool) != null &&
2479		(q = p.findNonEmptyStealQueue(1)) != null &&
2480		(b = q.base) - q.top < 0 &&
2481	<	(t = q.pollAt(b)) != null)
2481	>	(t = q.pollAt(b)) != null) {
2482	>	if (q.base - q.top < 0)
2483	>	p.signalWork(q);
2484		t.doExec();
2485	+	}
2486		}
2487
2488		// Exported methods
#	Line 2480 | Line 2558 | public class ForkJoinPool extends Abstra
2558		throw new IllegalArgumentException();
2559		this.factory = factory;
2560		this.ueh = handler;
2561	<	this.config = parallelism | (asyncMode? (FIFO_QUEUE << 16) : 0);
2561	>	this.config = parallelism | (asyncMode ? (FIFO_QUEUE << 16) : 0);
2562		long np = (long)(-parallelism); // offset ctl counts
2563		this.ctl = ((np << AC_SHIFT) & AC_MASK) | ((np << TC_SHIFT) & TC_MASK);
2564		int pn = nextPoolId();
#	Line 2505 | Line 2583 | public class ForkJoinPool extends Abstra
2583		}
2584
2585		/**
2586	<	* Returns the common pool instance.
2586	>	* Returns the common pool instance. This pool is statically
2587	>	* constructed; its run state is unaffected by attempts to
2588	>	* {@link #shutdown} or {@link #shutdownNow}.
2589		*
2590		* @return the common pool instance
2591		*/
#	Line 2838 | Line 2918 | public class ForkJoinPool extends Abstra
2918		WorkQueue[] ws; WorkQueue w;
2919		if ((ws = workQueues) != null) {
2920		for (int i = 0; i < ws.length; i += 2) {
2921	<	if ((w = ws[i]) != null && w.queueSize() != 0)
2921	>	if ((w = ws[i]) != null && !w.isEmpty())
2922		return true;
2923		}
2924		}
#	Line 3005 | Line 3085 | public class ForkJoinPool extends Abstra
3085		* commenced but not yet completed.  This method may be useful for
3086		* debugging. A return of {@code true} reported a sufficient
3087		* period after shutdown may indicate that submitted tasks have
3088	<	* ignored or suppressed interruption, or are waiting for IO,
3088	>	* ignored or suppressed interruption, or are waiting for I/O,
3089		* causing this executor not to properly terminate. (See the
3090		* advisory notes for class {@link ForkJoinTask} stating that
3091		* tasks should not normally entail blocking operations.  But if
#	Line 3160 | Line 3240 | public class ForkJoinPool extends Abstra
3240		if (t instanceof ForkJoinWorkerThread) {
3241		ForkJoinPool p = ((ForkJoinWorkerThread)t).pool;
3242		while (!blocker.isReleasable()) { // variant of helpSignal
3243	<	WorkQueue[] ws; WorkQueue q; int m, n, u;
3243	>	WorkQueue[] ws; WorkQueue q; int m, u;
3244		if ((ws = p.workQueues) != null && (m = ws.length - 1) >= 0) {
3245		for (int i = 0; i <= m; ++i) {
3246		if (blocker.isReleasable())
3247		return;
3248	<	if ((q = ws[i]) != null && (n = q.queueSize()) > 0) {
3249	<	p.signalWork(q, n);
3248	>	if ((q = ws[i]) != null && q.base - q.top < 0) {
3249	>	p.signalWork(q);
3250		if ((u = (int)(p.ctl >>> 32)) >= 0 ||
3251		(u >> UAC_SHIFT) >= 0)
3252		break;
#	Line 3245 | Line 3325 | public class ForkJoinPool extends Abstra
3325		submitters = new ThreadLocal<Submitter>();
3326		ForkJoinWorkerThreadFactory fac = defaultForkJoinWorkerThreadFactory =
3327		new DefaultForkJoinWorkerThreadFactory();
3328	+	modifyThreadPermission = new RuntimePermission("modifyThread");
3329	+
3330		/*
3331		* Establish common pool parameters.  For extra caution,
3332		* computations to set up common pool state are here; the
#	Line 3280 | Line 3362 | public class ForkJoinPool extends Abstra
3362		long ct = ((np << AC_SHIFT) & AC_MASK) | ((np << TC_SHIFT) & TC_MASK);
3363
3364		commonPool = new ForkJoinPool(par, ct, fac, handler);
3283	–	modifyThreadPermission = new RuntimePermission("modifyThread");
3365		}
3366
3367		/**

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