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

Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.145 by jsr166, Mon Nov 19 01:04:24 2012 UTC vs.
Revision 1.146 by dl, Mon Nov 19 18:12:42 2012 UTC

#	Line 37 | Line 37 | import java.util.concurrent.TimeUnit;
37		* ForkJoinPool}s may also be appropriate for use with event-style
38		* tasks that are never joined.
39		*
40	<	* <p>A static {@link #commonPool} is available and appropriate for
40	>	* <p>A static {@link #commonPool()} is available and appropriate for
41		* most applications. The common pool is used by any ForkJoinTask that
42		* is not explicitly submitted to a specified pool. Using the common
43		* pool normally reduces resource usage (its threads are slowly
#	Line 103 | Line 103 | import java.util.concurrent.TimeUnit;
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	+	=======
109		* exceptionHandler} -- the class name of a {@link
110		* java.lang.Thread.UncaughtExceptionHandler
111	+	>>>>>>> 1.111
112		* Thread.UncaughtExceptionHandler}. Upon any error in establishing
113		* these settings, default parameters are used.
114		*
#	Line 239 | Line 243 | public class ForkJoinPool extends Abstra
243		* enable shutdown.  When used as a lock, it is normally only very
244		* briefly held, so is nearly always available after at most a
245		* brief spin, but we use a monitor-based backup strategy to
246	<	* blocking when needed.
246	>	* block when needed.
247		*
248		* Recording WorkQueues.  WorkQueues are recorded in the
249		* "workQueues" array that is created upon first use and expanded
#	Line 248 | Line 252 | public class ForkJoinPool extends Abstra
252		* by a lock but the array is otherwise concurrently readable, and
253		* accessed directly.  To simplify index-based operations, the
254		* array size is always a power of two, and all readers must
255	<	* tolerate null slots. Worker queues are at odd indices Shared
255	>	* tolerate null slots. Worker queues are at odd indices. Shared
256		* (submission) queues are at even indices, up to a maximum of 64
257		* slots, to limit growth even if array needs to expand to add
258		* more workers. Grouping them together in this way simplifies and
#	Line 318 | Line 322 | public class ForkJoinPool extends Abstra
322		* general, pools will be over-signalled.  When a submission is
323		* added or another worker adds a task to a queue that is
324		* apparently empty, they signal waiting workers (or trigger
325	<	* creation of new ones if fewer than the given parallelism level
326	<	* -- see signalWork).  These primary signals are buttressed by
327	<	* signals whenever other threads scan for work or do not have a
328	<	* task to process. On most platforms, signalling (unpark)
329	<	* overhead time is noticeably long, and the time between
330	<	* signalling a thread and it actually making progress can be very
331	<	* noticeably long, so it is worth offloading these delays from
332	<	* critical paths as much as possible.
325	>	* creation of new ones if fewer than the given parallelism
326	>	* level).  These primary signals are buttressed by signals
327	>	* whenever other threads scan for work or do not have a task to
328	>	* process (including the case of leaving a hint to unparked
329	>	* threads to help signal others upon wakeup).  On most platforms,
330	>	* signalling (unpark) overhead time is noticeably long, and the
331	>	* time between signalling a thread and it actually making
332	>	* progress can be very noticeably long, so it is worth offloading
333	>	* these delays from critical paths as much as possible.
334		*
335		* Trimming workers. To release resources after periods of lack of
336		* use, a worker starting to wait when the pool is quiescent will
#	Line 393 | Line 398 | public class ForkJoinPool extends Abstra
398		* steals, rather than use per-task bookkeeping.  This sometimes
399		* requires a linear scan of workQueues array to locate stealers,
400		* but often doesn't because stealers leave hints (that may become
401	<	* stale/wrong) of where to locate them.  A stealHint is only a
402	<	* hint because a worker might have had multiple steals and the
403	<	* hint records only one of them (usually the most current).
404	<	* Hinting isolates cost to when it is needed, rather than adding
405	<	* to per-task overhead.  (2) It is "shallow", ignoring nesting
406	<	* and potentially cyclic mutual steals.  (3) It is intentionally
401	>	* stale/wrong) of where to locate them.  It is only a hint
402	>	* because a worker might have had multiple steals and the hint
403	>	* records only one of them (usually the most current).  Hinting
404	>	* isolates cost to when it is needed, rather than adding to
405	>	* per-task overhead.  (2) It is "shallow", ignoring nesting and
406	>	* potentially cyclic mutual steals.  (3) It is intentionally
407		* racy: field currentJoin is updated only while actively joining,
408		* which means that we miss links in the chain during long-lived
409		* tasks, GC stalls etc (which is OK since blocking in such cases
#	Line 525 | Line 530 | public class ForkJoinPool extends Abstra
530		* Default ForkJoinWorkerThreadFactory implementation; creates a
531		* new ForkJoinWorkerThread.
532		*/
533	<	static class DefaultForkJoinWorkerThreadFactory
533	>	static final class DefaultForkJoinWorkerThreadFactory
534		implements ForkJoinWorkerThreadFactory {
535	<	public ForkJoinWorkerThread newThread(ForkJoinPool pool) {
535	>	public final ForkJoinWorkerThread newThread(ForkJoinPool pool) {
536		return new ForkJoinWorkerThread(pool);
537		}
538		}
#	Line 598 | Line 603 | public class ForkJoinPool extends Abstra
603		* trades off slightly slower average field access for the sake of
604		* avoiding really bad worst-case access. (Until better JVM
605		* support is in place, this padding is dependent on transient
606	<	* properties of JVM field layout rules.)  We also take care in
602	<	* allocating, sizing and resizing the array. Non-shared queue
603	<	* arrays are initialized by workers before use. Others are
604	<	* allocated on first use.
606	>	* properties of JVM field layout rules.)
607		*/
608		static final class WorkQueue {
609		/**
#	Line 627 | Line 629 | public class ForkJoinPool extends Abstra
629		int seed;                  // for random scanning; initialize nonzero
630		volatile int eventCount;   // encoded inactivation count; < 0 if inactive
631		int nextWait;              // encoded record of next event waiter
632	<	final int mode;            // lifo, fifo, or shared
631	<	int nsteals;               // cumulative number of steals
632	>	int hint;                  // steal or signal hint (index)
633		int poolIndex;             // index of this queue in pool (or 0)
634	<	int stealHint;             // index of most recent known stealer
634	>	final int mode;            // 0: lifo, > 0: fifo, < 0: shared
635	>	int nsteals;               // number of steals
636		volatile int qlock;        // 1: locked, -1: terminate; else 0
637		volatile int base;         // index of next slot for poll
638		int top;                   // index of next slot for push
#	Line 640 | Line 642 | public class ForkJoinPool extends Abstra
642		volatile Thread parker;    // == owner during call to park; else null
643		volatile ForkJoinTask<?> currentJoin;  // task being joined in awaitJoin
644		ForkJoinTask<?> currentSteal; // current non-local task being executed
645	+
646		// Heuristic padding to ameliorate unfortunate memory placements
647		Object p00, p01, p02, p03, p04, p05, p06, p07;
648	<	Object p08, p09, p0a, p0b, p0c, p0d, p0e;
648	>	Object p08, p09, p0a, p0b, p0c;
649
650	<	WorkQueue(ForkJoinPool pool, ForkJoinWorkerThread owner, int mode) {
651	<	this.mode = mode;
650	>	WorkQueue(ForkJoinPool pool, ForkJoinWorkerThread owner, int mode,
651	>	int seed) {
652	>	this.array = new ForkJoinTask<?>[WorkQueue.INITIAL_QUEUE_CAPACITY];
653		this.pool = pool;
654		this.owner = owner;
655	<	// Place indices in the center of array (that is not yet allocated)
655	>	this.mode = mode;
656	>	this.seed = seed;
657	>	// Place indices in the center of array
658		base = top = INITIAL_QUEUE_CAPACITY >>> 1;
659		}
660
#	Line 661 | Line 667 | public class ForkJoinPool extends Abstra
667		* @throw RejectedExecutionException if array cannot be resized
668		*/
669		final void push(ForkJoinTask<?> task) {
670	<	ForkJoinPool p; ForkJoinTask<?>[] a;
671	<	int s = top, n;
672	<	if ((a = array) != null && a.length > (n = s + 1 - base)) {
670	>	ForkJoinTask<?>[] a; ForkJoinPool p;
671	>	int s = top, m, n;
672	>	if ((a = array) != null) {    // ignore if queue removed
673		U.putOrderedObject
674	<	(a, (((a.length - 1) & s) << ASHIFT) + ABASE, task);
675	<	top = s + 1;
676	<	if (n <= 1 && (p = pool) != null)
677	<	p.signalWork(this, 1);
674	>	(a, (((m = a.length - 1) & s) << ASHIFT) + ABASE, task);
675	>	if ((n = (top = s + 1) - base) <= 1) {
676	>	if ((p = pool) != null)
677	>	p.signalWork(this, 0);
678	>	}
679	>	else if (n >= m)
680	>	growArray();
681		}
673	–	else
674	–	fullPush(task, true);
682		}
683
684		/**
685		* Pushes a task if lock is free and array is either big
686	<	* enough or can be resized to be big enough. Note: a
680	<	* specialization of a common fast path of this method is in
681	<	* ForkJoinPool.externalPush. When called from a FJWT queue,
682	<	* this can fail only if the pool has been shut down or
683	<	* an out of memory error.
686	>	* enough or can be resized to be big enough.
687		*
688		* @param task the task. Caller must ensure non-null.
689	<	* @param owned if true, throw RJE on failure
689	>	* @return true if submitted
690		*/
691	<	final boolean fullPush(ForkJoinTask<?> task, boolean owned) {
692	<	ForkJoinPool p; ForkJoinTask<?>[] a;
693	<	if (owned) {
694	<	if (qlock < 0) // must be shutting down
695	<	throw new RejectedExecutionException();
696	<	}
697	<	else if (!U.compareAndSwapInt(this, QLOCK, 0, 1))
698	<	return false;
699	<	try {
700	<	int s = top, oldLen, len;
701	<	if ((a = array) == null)
702	<	a = array = new ForkJoinTask<?>[len=INITIAL_QUEUE_CAPACITY];
703	<	else if ((oldLen = a.length) > s + 1 - base)
704	<	len = oldLen;
705	<	else if ((len = oldLen << 1) > MAXIMUM_QUEUE_CAPACITY)
706	<	throw new RejectedExecutionException("Capacity exceeded");
707	<	else {
708	<	int oldMask, b;
709	<	ForkJoinTask<?>[] oldA = a;
710	<	a = array = new ForkJoinTask<?>[len];
711	<	if ((oldMask = oldLen - 1) >= 0 && s - (b = base) > 0) {
712	<	int mask = len - 1;
713	<	do {
714	<	ForkJoinTask<?> x;
715	<	int oldj = ((b & oldMask) << ASHIFT) + ABASE;
716	<	int j    = ((b &    mask) << ASHIFT) + ABASE;
717	<	x = (ForkJoinTask<?>)
718	<	U.getObjectVolatile(oldA, oldj);
719	<	if (x != null &&
720	<	U.compareAndSwapObject(oldA, oldj, x, null))
721	<	U.putObjectVolatile(a, j, x);
722	<	} while (++b != s);
723	<	}
724	<	}
725	<	U.putOrderedObject
726	<	(a, (((len - 1) & s) << ASHIFT) + ABASE, task);
727	<	top = s + 1;
728	<	} finally {
729	<	if (!owned)
730	<	qlock = 0;
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	>
713	>	/**
714	>	* Initializes or doubles the capacity of array. Call either
715	>	* by owner or with lock held -- it is OK for base, but not
716	>	* top, to move while resizings are in progress.
717	>	*/
718	>	final ForkJoinTask<?>[] growArray() {
719	>	ForkJoinTask<?>[] oldA = array;
720	>	int size = oldA != null ? oldA.length << 1 : INITIAL_QUEUE_CAPACITY;
721	>	if (size > MAXIMUM_QUEUE_CAPACITY)
722	>	throw new RejectedExecutionException("Queue capacity exceeded");
723	>	int oldMask, t, b;
724	>	ForkJoinTask<?>[] a = array = new ForkJoinTask<?>[size];
725	>	if (oldA != null && (oldMask = oldA.length - 1) >= 0 &&
726	>	(t = top) - (b = base) > 0) {
727	>	int mask = size - 1;
728	>	do {
729	>	ForkJoinTask<?> x;
730	>	int oldj = ((b & oldMask) << ASHIFT) + ABASE;
731	>	int j    = ((b &    mask) << ASHIFT) + ABASE;
732	>	x = (ForkJoinTask<?>)U.getObjectVolatile(oldA, oldj);
733	>	if (x != null &&
734	>	U.compareAndSwapObject(oldA, oldj, x, null))
735	>	U.putObjectVolatile(a, j, x);
736	>	} while (++b != t);
737		}
738	<	if ((p = pool) != null)
730	<	p.signalWork(this, 1);
731	<	return true;
738	>	return a;
739		}
740
741		/**
#	Line 980 | Line 987 | public class ForkJoinPool extends Abstra
987		if (t != null) {
988		(currentSteal = t).doExec();
989		currentSteal = null;
990	<	if (++nsteals < 0) {     // spill on overflow
984	<	ForkJoinPool p;
985	<	if ((p = pool) != null)
986	<	p.collectStealCount(this);
987	<	}
990	>	++nsteals;
991		if (top != base) {       // process remaining local tasks
992		if (mode == 0)
993		popAndExecAll();
#	Line 1057 | Line 1060 | public class ForkJoinPool extends Abstra
1060		}
1061		}
1062
1063	+	// static fields (initialized in static initializer below)
1064	+
1065	+	/**
1066	+	* Creates a new ForkJoinWorkerThread. This factory is used unless
1067	+	* overridden in ForkJoinPool constructors.
1068	+	*/
1069	+	public static final ForkJoinWorkerThreadFactory
1070	+	defaultForkJoinWorkerThreadFactory;
1071	+
1072		/**
1073		* Per-thread records for threads that submit to pools. Currently
1074		* holds only pseudo-random seed / index that is used to choose
#	Line 1077 | Line 1089 | public class ForkJoinPool extends Abstra
1089		Submitter(int s) { seed = s; }
1090		}
1091
1080	–	/** Property prefix for constructing common pool */
1081	–	private static final String propPrefix =
1082	–	"java.util.concurrent.ForkJoinPool.common.";
1083	–
1084	–	// static fields (initialized in static initializer below)
1085	–
1092		/**
1093	<	* Creates a new ForkJoinWorkerThread. This factory is used unless
1094	<	* overridden in ForkJoinPool constructors.
1093	>	* Per-thread submission bookkeeping. Shared across all pools
1094	>	* to reduce ThreadLocal pollution and because random motion
1095	>	* to avoid contention in one pool is likely to hold for others.
1096	>	* Lazily initialized on first submission (but null-checked
1097	>	* in other contexts to avoid unnecessary initialization).
1098		*/
1099	<	public static final ForkJoinWorkerThreadFactory
1091	<	defaultForkJoinWorkerThreadFactory;
1099	>	static final ThreadLocal<Submitter> submitters;
1100
1101		/**
1102		* Common (static) pool. Non-null for public use unless a static
#	Line 1105 | Line 1113 | public class ForkJoinPool extends Abstra
1113		private static final RuntimePermission modifyThreadPermission;
1114
1115		/**
1108	–	* Per-thread submission bookkeeping. Shared across all pools
1109	–	* to reduce ThreadLocal pollution and because random motion
1110	–	* to avoid contention in one pool is likely to hold for others.
1111	–	* Lazily initialized on first submission (but null-checked
1112	–	* in other contexts to avoid unnecessary initialization).
1113	–	*/
1114	–	static final ThreadLocal<Submitter> submitters;
1115	–
1116	–	/**
1116		* Common pool parallelism. Must equal commonPool.parallelism.
1117		*/
1118		static final int commonPoolParallelism;
#	Line 1248 | Line 1247 | public class ForkJoinPool extends Abstra
1247		static final int FIFO_QUEUE          =  1;
1248		static final int SHARED_QUEUE        = -1;
1249
1250	+	// bounds for #steps in scan loop -- must be power 2 minus 1
1251	+	private static final int MIN_SCAN    = 0x1ff;   // cover estimation slop
1252	+	private static final int MAX_SCAN    = 0x1ffff; // 4 * max workers
1253	+
1254		// Instance fields
1255
1256		/*
1257	<	* Field layout order in this class tends to matter more than one
1258	<	* would like. Runtime layout order is only loosely related to
1257	>	* Field layout of this class tends to matter more than one would
1258	>	* like. Runtime layout order is only loosely related to
1259		* declaration order and may differ across JVMs, but the following
1260		* empirically works OK on current JVMs.
1261		*/
1262		volatile long stealCount;                  // collects worker counts
1263		volatile long ctl;                         // main pool control
1261	–	final int parallelism;                     // parallelism level
1262	–	final int localMode;                       // per-worker scheduling mode
1263	–	volatile int indexSeed;                    // worker/submitter index seed
1264		volatile int plock;                        // shutdown status and seqLock
1265	+	volatile int indexSeed;                    // worker/submitter index seed
1266	+	final int config;                          // mode and parallelism level
1267		WorkQueue[] workQueues;                    // main registry
1268	<	final ForkJoinWorkerThreadFactory factory; // factory for new workers
1268	>	final ForkJoinWorkerThreadFactory factory;
1269		final Thread.UncaughtExceptionHandler ueh; // per-worker UEH
1270		final String workerNamePrefix;             // to create worker name string
1271
#	Line 1283 | Line 1285 | public class ForkJoinPool extends Abstra
1285		if (((ps = plock) & PL_LOCK) == 0 &&
1286		U.compareAndSwapInt(this, PLOCK, ps, nps = ps + PL_LOCK))
1287		return nps;
1288	<	else if (r == 0)
1289	<	r = ThreadLocalRandom.current().nextInt(); // randomize spins
1288	>	else if (r == 0) { // randomize spins if possible
1289	>	Thread t = Thread.currentThread(); WorkQueue w; Submitter z;
1290	>	if ((t instanceof ForkJoinWorkerThread) &&
1291	>	(w = ((ForkJoinWorkerThread)t).workQueue) != null)
1292	>	r = w.seed;
1293	>	else if ((z = submitters.get()) != null)
1294	>	r = z.seed;
1295	>	else
1296	>	r = 1;
1297	>	}
1298		else if (spins >= 0) {
1299		r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift
1300		if (r >= 0)
#	Line 1318 | Line 1328 | public class ForkJoinPool extends Abstra
1328		synchronized (this) { notifyAll(); }
1329		}
1330
1331	<	//  Registering and deregistering workers
1331	>	/**
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		/**
1344	<	* Callback from ForkJoinWorkerThread constructor to establish its
1345	<	* poolIndex and record its WorkQueue. To avoid scanning bias due
1346	<	* to packing entries in front of the workQueues array, we treat
1347	<	* the array as a simple power-of-two hash table using per-thread
1348	<	* seed as hash, expanding as needed.
1349	<	*
1350	<	* @param w the worker's queue
1351	<	*/
1352	<	final void registerWorker(WorkQueue w) {
1353	<	int s, ps; // generate a rarely colliding candidate index seed
1354	<	do {} while (!U.compareAndSwapInt(this, INDEXSEED,
1355	<	s = indexSeed, s += SEED_INCREMENT) ||
1356	<	s == 0); // skip 0
1344	>	* Performs secondary initialization, called when plock is zero.
1345	>	* Creates workQueue array and sets plock to a valid value.  The
1346	>	* lock body must be exception-free (so no try/finally) so we
1347	>	* optimistically allocate new array outside the lock and throw
1348	>	* away if (very rarely) not needed. (A similar tactic is used in
1349	>	* fullExternalPush.)  Because the plock seq value can eventually
1350	>	* wrap around zero, this method harmlessly fails to reinitialize
1351	>	* if workQueues exists, while still advancing plock.
1352	>	*/
1353	>	private void initWorkQueuesArray() {
1354	>	WorkQueue[] ws; int ps;
1355	>	int p = config & SMASK;        // find power of two table size
1356	>	int n = (p > 1) ? p - 1 : 1;   // ensure at least 2 slots
1357	>	n |= n >>> 1; n |= n >>> 2; n |= n >>> 4; n |= n >>> 8; n |= n >>> 16;
1358	>	WorkQueue[] nws = new WorkQueue[(n + 1) << 1];
1359		if (((ps = plock) & PL_LOCK) != 0 ||
1360		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1361		ps = acquirePlock();
1362	+	if ((ws = workQueues) == null || ws.length == 0)
1363	+	workQueues = nws;
1364		int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1365	<	try {
1366	<	WorkQueue[] ws;
1367	<	if (w != null && (ws = workQueues) != null) {
1368	<	w.seed = s;
1369	<	int n = ws.length, m = n - 1;
1370	<	int r = (s << 1) | 1;               // use odd-numbered indices
1371	<	if (ws[r &= m] != null) {           // collision
1372	<	int probes = 0;                 // step by approx half size
1373	<	int step = (n <= 4) ? 2 : ((n >>> 1) & EVENMASK) + 2;
1374	<	while (ws[r = (r + step) & m] != null) {
1375	<	if (++probes >= n) {
1376	<	workQueues = ws = Arrays.copyOf(ws, n <<= 1);
1377	<	m = n - 1;
1378	<	probes = 0;
1365	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1366	>	releasePlock(nps);
1367	>	long c; int u;
1368	>	if ((u = (int)((c = ctl) >>> 32)) < 0 && (int)c == 0) {
1369	>	long nc = (long)(((u + UTC_UNIT) & UTC_MASK) |
1370	>	((u + UAC_UNIT) & UAC_MASK)) << 32;
1371	>	if (U.compareAndSwapLong(this, CTL, c, nc))
1372	>	addWorker();
1373	>	}
1374	>
1375	>	}
1376	>
1377	>	//  Registering and deregistering workers
1378	>
1379	>	/**
1380	>	* Callback from ForkJoinWorkerThread to establish and record its
1381	>	* WorkQueue. To avoid scanning bias due to packing entries in
1382	>	* front of the workQueues array, we treat the array as a simple
1383	>	* power-of-two hash table using per-thread seed as hash,
1384	>	* expanding as needed.
1385	>	*
1386	>	* @param wt the worker thread
1387	>	*/
1388	>	final void registerWorker(ForkJoinWorkerThread wt) {
1389	>	if (wt != null && wt.workQueue == null) {
1390	>	int s, ps;    // generate a rarely colliding candidate index seed
1391	>	do {} while (!U.compareAndSwapInt(this, INDEXSEED, s = indexSeed,
1392	>	s += SEED_INCREMENT) ||
1393	>	s == 0); // skip 0
1394	>	WorkQueue w = new WorkQueue(this, wt, config >>> 16, s);
1395	>	if (((ps = plock) & PL_LOCK) != 0 ||
1396	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1397	>	ps = acquirePlock();
1398	>	int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1399	>	try {
1400	>	WorkQueue[] ws;
1401	>	if ((ws = workQueues) != null && wt.workQueue == null) {
1402	>	int n = ws.length, m = n - 1;
1403	>	int r = (s << 1) | 1;           // use odd-numbered indices
1404	>	if (ws[r &= m] != null) {       // collision
1405	>	int probes = 0;             // step by approx half size
1406	>	int step = (n <= 4) ? 2 : ((n >>> 1) & EVENMASK) + 2;
1407	>	while (ws[r = (r + step) & m] != null) {
1408	>	if (++probes >= n) {
1409	>	workQueues = ws = Arrays.copyOf(ws, n <<= 1);
1410	>	m = n - 1;
1411	>	probes = 0;
1412	>	}
1413		}
1414		}
1415	+	w.eventCount = w.poolIndex = r; // volatile write orders
1416	+	wt.workQueue = ws[r] = w;
1417		}
1418	<	w.eventCount = w.poolIndex = r;     // establish before recording
1419	<	ws[r] = w;
1418	>	} finally {
1419	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1420	>	releasePlock(nps);
1421		}
1361	–	} finally {
1362	–	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1363	–	releasePlock(nps);
1422		}
1423		}
1424
#	Line 1377 | Line 1435 | public class ForkJoinPool extends Abstra
1435		WorkQueue w = null;
1436		if (wt != null && (w = wt.workQueue) != null) {
1437		int ps;
1380	–	collectStealCount(w);
1438		w.qlock = -1;                // ensure set
1439	+	long ns = w.nsteals, sc;     // collect steal count
1440	+	do {} while (!U.compareAndSwapLong(this, STEALCOUNT,
1441	+	sc = stealCount, sc + ns));
1442		if (((ps = plock) & PL_LOCK) != 0 ||
1443		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1444		ps = acquirePlock();
#	Line 1403 | Line 1463 | public class ForkJoinPool extends Abstra
1463		if (!tryTerminate(false, false) && w != null) {
1464		w.cancelAll();                  // cancel remaining tasks
1465		if (w.array != null)            // suppress signal if never ran
1466	<	signalWork(null, 1);        // wake up or create replacement
1466	>	helpSignal(null, 0);        // wake up or create replacement
1467		if (ex == null)                 // help clean refs on way out
1468		ForkJoinTask.helpExpungeStaleExceptions();
1469		}
#	Line 1412 | Line 1472 | public class ForkJoinPool extends Abstra
1472		ForkJoinTask.rethrow(ex);
1473		}
1474
1415	–	/**
1416	–	* Collect worker steal count into total. Called on termination
1417	–	* and upon int overflow of local count. (There is a possible race
1418	–	* in the latter case vs any caller of getStealCount, which can
1419	–	* make its results less accurate than usual.)
1420	–	*/
1421	–	final void collectStealCount(WorkQueue w) {
1422	–	if (w != null) {
1423	–	long sc;
1424	–	int ns = w.nsteals;
1425	–	w.nsteals = 0; // handle overflow
1426	–	long steals = (ns >= 0) ? ns : 1L + (long)(Integer.MAX_VALUE);
1427	–	do {} while (!U.compareAndSwapLong(this, STEALCOUNT,
1428	–	sc = stealCount, sc + steals));
1429	–	}
1430	–	}
1431	–
1475		// Submissions
1476
1477		/**
#	Line 1445 | Line 1488 | public class ForkJoinPool extends Abstra
1488		(ws = workQueues) != null && (m = (ws.length - 1)) >= 0 &&
1489		(q = ws[m & z.seed & SQMASK]) != null &&
1490		U.compareAndSwapInt(q, QLOCK, 0, 1)) { // lock
1491	<	int s = q.top, n;
1492	<	if ((a = q.array) != null && a.length > (n = s + 1 - q.base)) {
1493	<	U.putObject(a, (long)(((a.length - 1) & s) << ASHIFT) + ABASE,
1451	<	task);
1491	>	int b = q.base, s = q.top, n, an;
1492	>	if ((a = q.array) != null && (an = a.length) > (n = s + 1 - b)) {
1493	>	U.putObject(a, (long)(((an - 1) & s) << ASHIFT) + ABASE, task);
1494		q.top = s + 1;                     // push on to deque
1495		q.qlock = 0;
1496	<	if (n <= 1)
1497	<	signalWork(q, 1);
1496	>	if (n <= 2)
1497	>	signalWork(q, 0);
1498		return;
1499		}
1500		q.qlock = 0;
#	Line 1463 | Line 1505 | public class ForkJoinPool extends Abstra
1505		/**
1506		* Full version of externalPush. This method is called, among
1507		* other times, upon the first submission of the first task to the
1508	<	* pool, so must perform secondary initialization: creating
1509	<	* workQueue array and setting plock to a valid value. It also
1510	<	* detects first submission by an external thread by looking up
1511	<	* its ThreadLocal, and creates a new shared queue if the one at
1512	<	* index if empty or contended. The lock bodies must be
1513	<	* exception-free (so no try/finally) so we optimistically
1514	<	* allocate new queues/arrays outside the locks and throw them
1473	<	* away if (very rarely) not needed. Note that the plock seq value
1474	<	* can eventually wrap around zero, but if so harmlessly fails to
1475	<	* reinitialize.
1508	>	* pool, so must perform secondary initialization (via
1509	>	* initWorkQueuesArray). It also detects first submission by an
1510	>	* external thread by looking up its ThreadLocal, and creates a
1511	>	* new shared queue if the one at index if empty or contended. The
1512	>	* lock body must be exception-free (so no try/finally) so we
1513	>	* optimistically allocate new queues outside the lock and throw
1514	>	* them away if (very rarely) not needed.
1515		*/
1516		private void fullExternalPush(ForkJoinTask<?> task) {
1517	<	for (Submitter z = null;;) {
1518	<	WorkQueue[] ws; WorkQueue q; int ps, m, r, s;
1519	<	if ((ps = plock) < 0)
1517	>	int r = 0;
1518	>	for (Submitter z = submitters.get();;) {
1519	>	WorkQueue[] ws; WorkQueue q; int ps, m, k;
1520	>	if (z == null) {
1521	>	if (U.compareAndSwapInt(this, INDEXSEED, r = indexSeed,
1522	>	r += SEED_INCREMENT) && r != 0)
1523	>	submitters.set(z = new Submitter(r));
1524	>	}
1525	>	else if (r == 0) {               // move to a different index
1526	>	r = z.seed;
1527	>	r ^= r << 13;                // same xorshift as WorkQueues
1528	>	r ^= r >>> 17;
1529	>	z.seed = r ^ (r << 5);
1530	>	}
1531	>	else if ((ps = plock) < 0)
1532		throw new RejectedExecutionException();
1533	<	else if ((ws = workQueues) == null || (m = ws.length - 1) < 0) {
1534	<	int n = parallelism - 1; n |= n >>> 1; n |= n >>> 2;
1535	<	n |= n >>> 4; n |= n >>> 8; n |= n >>> 16;
1536	<	WorkQueue[] nws = new WorkQueue[(n + 1) << 1]; // power of two
1537	<	if ((ps & PL_LOCK) != 0 ||
1533	>	else if (ps == 0 || (ws = workQueues) == null ||
1534	>	(m = ws.length - 1) < 0)
1535	>	initWorkQueuesArray();
1536	>	else if ((q = ws[k = r & m & SQMASK]) != null) {
1537	>	if (q.trySharedPush(task))
1538	>	return;
1539	>	else
1540	>	r = 0; // move on contention
1541	>	}
1542	>	else if (((ps = plock) & PL_LOCK) == 0) { // create new queue
1543	>	q = new WorkQueue(this, null, SHARED_QUEUE, r);
1544	>	if (((ps = plock) & PL_LOCK) != 0 ||
1545		!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1546		ps = acquirePlock();
1547	<	if ((ws = workQueues) == null)
1548	<	workQueues = nws;
1547	>	if ((ws = workQueues) != null && k < ws.length && ws[k] == null)
1548	>	ws[k] = q;
1549		int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1550		if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1551		releasePlock(nps);
1552		}
1553	<	else if (z == null && (z = submitters.get()) == null) {
1554	<	if (U.compareAndSwapInt(this, INDEXSEED,
1497	<	s = indexSeed, s += SEED_INCREMENT) &&
1498	<	s != 0) // skip 0
1499	<	submitters.set(z = new Submitter(s));
1500	<	}
1501	<	else {
1502	<	int k = (r = z.seed) & m & SQMASK;
1503	<	if ((q = ws[k]) == null && (ps & PL_LOCK) == 0) {
1504	<	(q = new WorkQueue(this, null, SHARED_QUEUE)).poolIndex = k;
1505	<	if (((ps = plock) & PL_LOCK) != 0 ||
1506	<	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1507	<	ps = acquirePlock();
1508	<	WorkQueue w = null;
1509	<	if ((ws = workQueues) != null && k < ws.length &&
1510	<	(w = ws[k]) == null)
1511	<	ws[k] = q;
1512	<	else
1513	<	q = w;
1514	<	int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1515	<	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1516	<	releasePlock(nps);
1517	<	}
1518	<	if (q != null && q.qlock == 0 && q.fullPush(task, false))
1519	<	return;
1520	<	r ^= r << 13;                // same xorshift as WorkQueues
1521	<	r ^= r >>> 17;
1522	<	z.seed = r ^= r << 5;        // move to a different index
1523	<	}
1553	>	else
1554	>	r = 0; // try elsewhere while lock held
1555		}
1556		}
1557
#	Line 1541 | Line 1572 | public class ForkJoinPool extends Abstra
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.
1575	>	* @param signals the target number of signals (at least one --
1576	>	* if argument is zero also sets signallee hint if parked).
1577		*/
1578		final void signalWork(WorkQueue q, int signals) {
1579	<	long c; int e, u, i; WorkQueue[] ws; WorkQueue w; Thread p;
1579	>	long c; int e, u, i, s; WorkQueue[] ws; WorkQueue w; Thread p;
1580		while ((u = (int)((c = ctl) >>> 32)) < 0) {
1581		if ((e = (int)c) > 0) {
1582		if ((ws = workQueues) != null && ws.length > (i = e & SMASK) &&
#	Line 1553 | Line 1585 | public class ForkJoinPool extends Abstra
1585		((long)(u + UAC_UNIT) << 32));
1586		if (U.compareAndSwapLong(this, CTL, c, nc)) {
1587		w.eventCount = (e + E_SEQ) & E_MASK;
1588	<	if ((p = w.parker) != null)
1588	>	if ((p = w.parker) != null) {
1589	>	if (q != null && signals == 0)
1590	>	w.hint = q.poolIndex;
1591		U.unpark(p);
1592	+	}
1593		if (--signals <= 0)
1594		break;
1595		}
1596	<	else
1597	<	signals = 1;
1563	<	if ((q != null && q.queueSize() == 0))
1596	>	if (q != null && (s = q.queueSize()) <= signals &&
1597	>	(signals = s) <= 0)
1598		break;
1599		}
1600		else
#	Line 1570 | Line 1604 | public class ForkJoinPool extends Abstra
1604		long nc = (long)(((u + UTC_UNIT) & UTC_MASK) |
1605		((u + UAC_UNIT) & UAC_MASK)) << 32;
1606		if (U.compareAndSwapLong(this, CTL, c, nc)) {
1607	<	ForkJoinWorkerThread wt = null;
1574	<	Throwable ex = null;
1575	<	boolean started = false;
1576	<	try {
1577	<	ForkJoinWorkerThreadFactory fac;
1578	<	if ((fac = factory) != null &&
1579	<	(wt = fac.newThread(this)) != null) {
1580	<	wt.start();
1581	<	started = true;
1582	<	}
1583	<	} catch (Throwable rex) {
1584	<	ex = rex;
1585	<	}
1586	<	if (!started)
1587	<	deregisterWorker(wt, ex); // adjust counts on failure
1607	>	addWorker();
1608		break;
1609		}
1610		}
#	Line 1599 | Line 1619 | public class ForkJoinPool extends Abstra
1619		* Top-level runloop for workers, called by ForkJoinWorkerThread.run.
1620		*/
1621		final void runWorker(WorkQueue w) {
1622	<	// initialize queue array in this thread
1623	<	w.array = new ForkJoinTask<?>[WorkQueue.INITIAL_QUEUE_CAPACITY];
1604	<	do { w.runTask(scan(w)); } while (w.qlock >= 0);
1622	>	if (w != null) // skip on initialization failure
1623	>	do { w.runTask(scan(w)); } while (w.qlock >= 0);
1624		}
1625
1626		/**
#	Line 1612 | Line 1631 | public class ForkJoinPool extends Abstra
1631		* contention, or state changes that indicate possible success on
1632		* re-invocation.
1633		*
1634	<	* The scan searches for tasks across a random permutation of
1635	<	* queues (starting at a random index and stepping by a random
1636	<	* relative prime, checking each at least once).  The scan
1637	<	* terminates upon either finding a non-empty queue, or completing
1638	<	* the sweep. If the worker is not inactivated, it takes and
1639	<	* returns a task from this queue. Otherwise, if not activated, it
1640	<	* signals workers (that may include itself) and returns so caller
1641	<	* can retry. Also returns for trtry if the worker array may have
1642	<	* changed during an empty scan.  On failure to find a task, we
1643	<	* take one of the following actions, after which the caller will
1644	<	* retry calling this method unless terminated.
1634	>	* The scan searches for tasks across queues (starting at a random
1635	>	* index, and relying on registerWorker to irregularly scatter
1636	>	* them within array to avoid bias), checking each at least twice.
1637	>	* The scan terminates upon either finding a non-empty queue, or
1638	>	* completing the sweep. If the worker is not inactivated, it
1639	>	* takes and returns a task from this queue. Otherwise, if not
1640	>	* activated, it signals workers (that may include itself) and
1641	>	* returns so caller can retry. Also returns for true if the
1642	>	* worker array may have changed during an empty scan.  On failure
1643	>	* to find a task, we take one of the following actions, after
1644	>	* which the caller will retry calling this method unless
1645	>	* terminated.
1646		*
1647		* * If pool is terminating, terminate the worker.
1648		*
#	Line 1639 | Line 1659 | public class ForkJoinPool extends Abstra
1659		* @return a task or null if none found
1660		*/
1661		private final ForkJoinTask<?> scan(WorkQueue w) {
1662	<	WorkQueue[] ws; WorkQueue q;           // first update random seed
1663	<	int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
1664	<	int ps = plock, m;                     // volatile read order matters
1665	<	if ((ws = workQueues) != null && (m = ws.length - 1) > 0) {
1666	<	int ec = w.eventCount;             // ec is negative if inactive
1667	<	int step = (r >>> 16) | 1;         // relatively prime
1668	<	for (int j = (m + 1) << 2;  ; --j, r += step) {
1669	<	ForkJoinTask<?> t; ForkJoinTask<?>[] a; int b, n;
1670	<	if ((q = ws[r & m]) != null && (b = q.base) - q.top < 0 &&
1651	<	(a = q.array) != null) {   // probably nonempty
1662	>	WorkQueue[] ws; int m, hint;
1663	>	int ps = plock;                          // read plock before ws
1664	>	if (w != null && (ws = workQueues) != null && (m = ws.length - 1) >= 0) {
1665	>	int ec = w.eventCount;               // ec is negative if inactive
1666	>	int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5;
1667	>	for (int j = ((m + m + 1) | MIN_SCAN) & MAX_SCAN; ; --j) {
1668	>	WorkQueue q; ForkJoinTask<?>[] a; int b;
1669	>	if ((q = ws[(r + j) & m]) != null && (b = q.base) - q.top < 0 &&
1670	>	(a = q.array) != null) {     // probably nonempty
1671		int i = (((a.length - 1) & b) << ASHIFT) + ABASE;
1672	<	t = (ForkJoinTask<?>)U.getObjectVolatile(a, i);
1672	>	ForkJoinTask<?> t = (ForkJoinTask<?>)
1673	>	U.getObjectVolatile(a, i);
1674		if (q.base == b && ec >= 0 && t != null &&
1675		U.compareAndSwapObject(a, i, t, null)) {
1676	<	if ((n = q.top - (q.base = b + 1)) > 0)
1677	<	signalWork(q, n);
1678	<	return t;              // taken
1679	<	}
1680	<	if (j < m || (ec < 0 && (ec = w.eventCount) < 0)) {
1681	<	if ((n = q.queueSize() - 1) > 0)
1682	<	signalWork(q, n);
1683	<	break;                 // let caller retry after signal
1676	>	if ((q.base = b + 1) - q.top < 0)
1677	>	signalWork(q, 0);
1678	>	return t;                // taken
1679	>	}
1680	>	else if (ec < 0 || j < m) {  // cannot take or cannot rescan
1681	>	w.hint = q.poolIndex;    // use hint below
1682	>	break;                   // let caller retry after signal
1683	>	}
1684	>	}
1685	>	else if (j < 0) { // end of scan; in loop to simplify code
1686	>	long c, sc; int e, ns;
1687	>	if ((ns = w.nsteals) != 0) {
1688	>	if (U.compareAndSwapLong(this, STEALCOUNT,
1689	>	sc = stealCount, sc + ns))
1690	>	w.nsteals = 0;       // collect steals
1691		}
1692	<	}
1666	<	else if (j < 0) {              // end of scan
1667	<	long c = ctl; int e;
1668	<	if (plock != ps)           // incomplete sweep
1692	>	else if (plock != ps)        // ws may have changed
1693		break;
1694	<	if ((e = (int)c) < 0)      // pool is terminating
1695	<	w.qlock = -1;
1696	<	else if (ec >= 0) {        // try to enqueue/inactivate
1694	>	else if ((e = (int)(c = ctl)) < 0)
1695	>	w.qlock = -1;            // pool is terminating
1696	>	else if (ec >= 0) {          // try to enqueue/inactivate
1697		long nc = ((long)ec |
1698		((c - AC_UNIT) & (AC_MASK|TC_MASK)));
1699	<	w.nextWait = e;
1700	<	w.eventCount = ec | INT_SIGN; // mark as inactive
1699	>	w.nextWait = e;          // link and mark inactive
1700	>	w.hint = -1;             // use hint if set while parked
1701	>	w.eventCount = ec | INT_SIGN;
1702		if (ctl != c ||
1703		!U.compareAndSwapLong(this, CTL, c, nc))
1704	<	w.eventCount = ec; // unmark on CAS failure
1705	<	else if ((int)(c >> AC_SHIFT) == 1 - parallelism)
1706	<	idleAwaitWork(w, nc, c);  // quiescent
1704	>	w.eventCount = ec;  // unmark on CAS failure
1705	>	else if ((int)(c >> AC_SHIFT) == 1 - (config & SMASK))
1706	>	idleAwaitWork(w, nc, c);
1707		}
1708	<	else if (w.seed >= 0 && w.eventCount < 0) {
1708	>	else if (w.eventCount < 0) { // block
1709		Thread wt = Thread.currentThread();
1710	<	Thread.interrupted();  // clear status
1710	>	Thread.interrupted();    // clear status
1711		U.putObject(wt, PARKBLOCKER, this);
1712	<	w.parker = wt;         // emulate LockSupport.park
1713	<	if (w.eventCount < 0)  // recheck
1712	>	w.parker = wt;           // emulate LockSupport.park
1713	>	if (w.eventCount < 0)    // recheck
1714		U.park(false, 0L);
1715		w.parker = null;
1716		U.putObject(wt, PARKBLOCKER, null);
#	Line 1693 | Line 1718 | public class ForkJoinPool extends Abstra
1718		break;
1719		}
1720		}
1721	+	if ((hint = w.hint) >= 0) {          // help signal
1722	+	WorkQueue[] vs; WorkQueue v; int k;
1723	+	w.hint = -1;                     // suppress resignal
1724	+	if ((vs = workQueues) != null && hint < vs.length &&
1725	+	(v = vs[hint]) != null && (k = v.base - v.top) < -1)
1726	+	signalWork(v, 1 - k);
1727	+	}
1728		}
1729		return null;
1730		}
#	Line 1710 | Line 1742 | public class ForkJoinPool extends Abstra
1742		* @param prevCtl the ctl value to restore if thread is terminated
1743		*/
1744		private void idleAwaitWork(WorkQueue w, long currentCtl, long prevCtl) {
1745	<	if (w.eventCount < 0 &&
1746	<	(this == commonPool || !tryTerminate(false, false)) &&
1715	<	(int)prevCtl != 0) {
1745	>	if (w != null && w.eventCount < 0 &&
1746	>	!tryTerminate(false, false) && (int)prevCtl != 0) {
1747		int dc = -(short)(currentCtl >>> TC_SHIFT);
1748		long parkTime = dc < 0 ? FAST_IDLE_TIMEOUT: (dc + 1) * IDLE_TIMEOUT;
1749		long deadline = System.nanoTime() + parkTime - 100000L; // 1ms slop
#	Line 1731 | Line 1762 | public class ForkJoinPool extends Abstra
1762		U.compareAndSwapLong(this, CTL, currentCtl, prevCtl)) {
1763		w.eventCount = (w.eventCount + E_SEQ) | E_MASK;
1764		w.qlock = -1;   // shrink
1765	+	w.hint = -1;    // suppress helping
1766		break;
1767		}
1768		}
#	Line 1738 | Line 1770 | public class ForkJoinPool extends Abstra
1770		}
1771
1772		/**
1773	<	* Scans through queues looking for work while joining a task;
1774	<	* if any are present, signals.
1773	>	* Scans through queues looking for work (optionally, while
1774	>	* joining a task); if any are present, signals. May return early
1775	>	* if more signalling is detectably unneeded.
1776		*
1777	<	* @param task to return early if done
1777	>	* @param task if non-null, return early if done
1778		* @param origin an index to start scan
1779		*/
1780		final int helpSignal(ForkJoinTask<?> task, int origin) {
1781	<	WorkQueue[] ws; WorkQueue q; int m, n, s;
1782	<	if (task != null && (ws = workQueues) != null &&
1750	<	(m = ws.length - 1) >= 0) {
1781	>	WorkQueue[] ws; WorkQueue q; int m, n, s, u;
1782	>	if ((ws = workQueues) != null && (m = ws.length - 1) >= 0) {
1783		for (int i = 0; i <= m; ++i) {
1784	<	if ((s = task.status) < 0)
1784	>	if (task != null && (s = task.status) < 0)
1785		return s;
1786		if ((q = ws[(i + origin) & m]) != null &&
1787		(n = q.queueSize()) > 0) {
1788		signalWork(q, n);
1789	<	if ((int)(ctl >> AC_SHIFT) >= 0)
1789	>	if ((u = (int)(ctl >>> 32)) >= 0 || (u >> UAC_SHIFT) >= 0)
1790		break;
1791		}
1792		}
#	Line 1793 | Line 1825 | public class ForkJoinPool extends Abstra
1825		}
1826		if ((ws = workQueues) == null || (m = ws.length - 1) <= 0)
1827		break restart;              // shutting down
1828	<	if ((v = ws[h = (j.stealHint | 1) & m]) == null ||
1828	>	if ((v = ws[h = (j.hint | 1) & m]) == null ||
1829		v.currentSteal != subtask) {
1830		for (int origin = h;;) {    // find stealer
1831		if (((h = (h + 2) & m) & 15) == 1 &&
#	Line 1801 | Line 1833 | public class ForkJoinPool extends Abstra
1833		continue restart;   // occasional staleness check
1834		if ((v = ws[h]) != null &&
1835		v.currentSteal == subtask) {
1836	<	j.stealHint = h;    // save hint
1836	>	j.hint = h;        // save hint
1837		break;
1838		}
1839		if (h == origin)
#	Line 1858 | Line 1890 | public class ForkJoinPool extends Abstra
1890		*
1891		*/
1892		private int helpComplete(ForkJoinTask<?> task, int mode) {
1893	<	WorkQueue[] ws; WorkQueue q; int m, n, s;
1893	>	WorkQueue[] ws; WorkQueue q; int m, n, s, u;
1894		if (task != null && (ws = workQueues) != null &&
1895		(m = ws.length - 1) >= 0) {
1896		for (int j = 1, origin = j;;) {
#	Line 1866 | Line 1898 | public class ForkJoinPool extends Abstra
1898		return s;
1899		if ((q = ws[j & m]) != null && q.pollAndExecCC(task)) {
1900		origin = j;
1901	<	if (mode == SHARED_QUEUE && (int)(ctl >> AC_SHIFT) >= 0)
1901	>	if (mode == SHARED_QUEUE &&
1902	>	((u = (int)(ctl >>> 32)) >= 0 || (u >> UAC_SHIFT) >= 0))
1903		break;
1904		}
1905		else if ((j = (j + 2) & m) == origin)
#	Line 1884 | Line 1917 | public class ForkJoinPool extends Abstra
1917		* may become starved.
1918		*/
1919		final boolean tryCompensate() {
1920	<	int pc = parallelism, e, u, i, tc; long c;
1920	>	int pc = config & SMASK, e, i, tc; long c;
1921		WorkQueue[] ws; WorkQueue w; Thread p;
1922	<	if ((e = (int)(c = ctl)) >= 0 && (ws = workQueues) != null) {
1922	>	if ((ws = workQueues) != null && (e = (int)(c = ctl)) >= 0) {
1923		if (e != 0 && (i = e & SMASK) < ws.length &&
1924		(w = ws[i]) != null && w.eventCount == (e | INT_SIGN)) {
1925		long nc = ((long)(w.nextWait & E_MASK) |
#	Line 1898 | Line 1931 | public class ForkJoinPool extends Abstra
1931		return true;   // replace with idle worker
1932		}
1933		}
1934	<	else if ((short)((u = (int)(c >>> 32)) >>> UTC_SHIFT) >= 0 &&
1935	<	(u >> UAC_SHIFT) + pc > 1) {
1934	>	else if ((tc = (short)(c >>> TC_SHIFT)) >= 0 &&
1935	>	(int)(c >> AC_SHIFT) + pc > 1) {
1936		long nc = ((c - AC_UNIT) & AC_MASK) | (c & ~AC_MASK);
1937		if (U.compareAndSwapLong(this, CTL, c, nc))
1938	<	return true;    // no compensation
1938	>	return true;   // no compensation
1939		}
1940	<	else if ((tc = u + pc) < MAX_CAP) {
1940	>	else if (tc + pc < MAX_CAP) {
1941		long nc = ((c + TC_UNIT) & TC_MASK) | (c & ~TC_MASK);
1942		if (U.compareAndSwapLong(this, CTL, c, nc)) {
1943	<	Throwable ex = null;
1944	<	ForkJoinWorkerThread wt = null;
1912	<	try {
1913	<	ForkJoinWorkerThreadFactory fac;
1914	<	if ((fac = factory) != null &&
1915	<	(wt = fac.newThread(this)) != null) {
1916	<	wt.start();
1917	<	return true;
1918	<	}
1919	<	} catch (Throwable rex) {
1920	<	ex = rex;
1921	<	}
1922	<	deregisterWorker(wt, ex); // adjust counts etc
1943	>	addWorker();
1944	>	return true;
1945		}
1946		}
1947		}
#	Line 1945 | Line 1967 | public class ForkJoinPool extends Abstra
1967		(s = helpSignal(task, joiner.poolIndex)) >= 0 &&
1968		(task instanceof CountedCompleter))
1969		s = helpComplete(task, LIFO_QUEUE);
1970	+	int k = 0; // to perform pre-block yield for politeness
1971		while (s >= 0 && (s = task.status) >= 0) {
1972		if ((joiner.queueSize() > 0 ||           // try helping
1973		(s = tryHelpStealer(joiner, task)) == 0) &&
1974	<	(s = task.status) >= 0 && tryCompensate()) {
1975	<	if (task.trySetSignal() && (s = task.status) >= 0) {
1976	<	synchronized (task) {
1977	<	if (task.status >= 0) {
1978	<	try {                // see ForkJoinTask
1979	<	task.wait();     //  for explanation
1980	<	} catch (InterruptedException ie) {
1974	>	(s = task.status) >= 0) {
1975	>	if (k < 3) {
1976	>	if (++k < 3)
1977	>	s = helpSignal(task, joiner.poolIndex);
1978	>	else
1979	>	Thread.yield();
1980	>	}
1981	>	else if (!tryCompensate())
1982	>	k = 0;
1983	>	else {
1984	>	if (task.trySetSignal() && (s = task.status) >= 0) {
1985	>	synchronized (task) {
1986	>	if (task.status >= 0) {
1987	>	try {                // see ForkJoinTask
1988	>	task.wait();     //  for explanation
1989	>	} catch (InterruptedException ie) {
1990	>	}
1991		}
1992	+	else
1993	+	task.notifyAll();
1994		}
1960	–	else
1961	–	task.notifyAll();
1995		}
1996	+	long c;                          // re-activate
1997	+	do {} while (!U.compareAndSwapLong
1998	+	(this, CTL, c = ctl, c + AC_UNIT));
1999		}
1964	–	long c;                          // re-activate
1965	–	do {} while (!U.compareAndSwapLong
1966	–	(this, CTL, c = ctl, c + AC_UNIT));
2000		}
2001		}
2002		joiner.currentJoin = prevJoin;
#	Line 2007 | Line 2040 | public class ForkJoinPool extends Abstra
2040		* @param r a (random) seed for scanning
2041		*/
2042		private WorkQueue findNonEmptyStealQueue(int r) {
2010	–	int step = (r >>> 16) | 1;
2043		for (WorkQueue[] ws;;) {
2044	<	int ps = plock, m;
2044	>	int ps = plock, m, n;
2045		if ((ws = workQueues) == null || (m = ws.length - 1) < 1)
2046		return null;
2047	<	for (int j = (m + 1) << 2; ; r += step) {
2048	<	WorkQueue q = ws[((r << 1) | 1) & m];
2049	<	if (q != null && q.queueSize() > 0)
2047	>	for (int j = (m + 1) << 2; ;) {
2048	>	WorkQueue q = ws[(((r + j) << 1) | 1) & m];
2049	>	if (q != null && (n = q.queueSize()) > 0) {
2050	>	if (n > 1)
2051	>	signalWork(q, 0);
2052		return q;
2053	+	}
2054		else if (--j < 0) {
2055		if (plock == ps)
2056		return null;
#	Line 2058 | Line 2093 | public class ForkJoinPool extends Abstra
2093		}
2094		else
2095		c = ctl;        // re-increment on exit
2096	<	if ((int)(c >> AC_SHIFT) + parallelism == 0) {
2096	>	if ((int)(c >> AC_SHIFT) + (config & SMASK) == 0) {
2097		do {} while (!U.compareAndSwapLong
2098		(this, CTL, c = ctl, c + AC_UNIT));
2099		break;
#	Line 2133 | Line 2168 | public class ForkJoinPool extends Abstra
2168		static int getSurplusQueuedTaskCount() {
2169		Thread t; ForkJoinWorkerThread wt; ForkJoinPool pool; WorkQueue q;
2170		if (((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)) {
2171	<	int b = (q = (wt = (ForkJoinWorkerThread)t).workQueue).base;
2172	<	int p = (pool = wt.pool).parallelism;
2171	>	int p = (pool = (wt = (ForkJoinWorkerThread)t).pool).config & SMASK;
2172	>	int n = (q = wt.workQueue).top - q.base;
2173		int a = (int)(pool.ctl >> AC_SHIFT) + p;
2174	<	return q.top - b - (a > (p >>>= 1) ? 0 :
2175	<	a > (p >>>= 1) ? 1 :
2176	<	a > (p >>>= 1) ? 2 :
2177	<	a > (p >>>= 1) ? 4 :
2178	<	8);
2174	>	return n - (a > (p >>>= 1) ? 0 :
2175	>	a > (p >>>= 1) ? 1 :
2176	>	a > (p >>>= 1) ? 2 :
2177	>	a > (p >>>= 1) ? 4 :
2178	>	8);
2179		}
2180		return 0;
2181		}
#	Line 2166 | Line 2201 | public class ForkJoinPool extends Abstra
2201		return false;
2202		for (long c;;) {
2203		if (((c = ctl) & STOP_BIT) != 0) {      // already terminating
2204	<	if ((short)(c >>> TC_SHIFT) == -parallelism) {
2204	>	if ((short)(c >>> TC_SHIFT) == -(config & SMASK)) {
2205		synchronized (this) {
2206		notifyAll();                // signal when 0 workers
2207		}
#	Line 2185 | Line 2220 | public class ForkJoinPool extends Abstra
2220		releasePlock(nps);
2221		}
2222		if (!now) {                             // check if idle & no tasks
2223	<	if ((int)(c >> AC_SHIFT) != -parallelism ||
2223	>	if ((int)(c >> AC_SHIFT) != -(config & SMASK) ||
2224		hasQueuedSubmissions())
2225		return false;
2226		// Check for unqueued inactive workers. One pass suffices.
#	Line 2287 | Line 2322 | public class ForkJoinPool extends Abstra
2322		if (q != null && (a = q.array) != null && (m = (a.length - 1)) >= 0 &&
2323		root != null && root.status >= 0) {
2324		for (;;) {
2325	<	int s; Object o; CountedCompleter<?> task = null;
2325	>	int s, u; Object o; CountedCompleter<?> task = null;
2326		if ((s = q.top) - q.base > 0) {
2327		long j = ((m & (s - 1)) << ASHIFT) + ABASE;
2328		if ((o = U.getObject(a, j)) != null &&
#	Line 2310 | Line 2345 | public class ForkJoinPool extends Abstra
2345		}
2346		if (task != null)
2347		task.doExec();
2348	<	if (root.status < 0 || (int)(ctl >> AC_SHIFT) >= 0)
2348	>	if (root.status < 0 ||
2349	>	(u = (int)(ctl >>> 32)) >= 0 || (u >> UAC_SHIFT) >= 0)
2350		break;
2351		if (task == null) {
2352		if (helpSignal(root, q.poolIndex) >= 0)
#	Line 2329 | Line 2365 | public class ForkJoinPool extends Abstra
2365		// Some hard-to-avoid overlap with tryExternalUnpush
2366		ForkJoinPool p; WorkQueue[] ws; WorkQueue q, w; Submitter z;
2367		ForkJoinTask<?>[] a;  int m, s, n; long j;
2368	<	if (t != null && t.status >= 0 &&
2368	>	if (t != null &&
2369		(z = submitters.get()) != null &&
2370		(p = commonPool) != null &&
2371		(ws = p.workQueues) != null &&
2372		(m = ws.length - 1) >= 0 &&
2373		(q = ws[m & z.seed & SQMASK]) != null &&
2374	<	(a = q.array) != null) {
2374	>	(a = q.array) != null &&
2375	>	t.status >= 0) {
2376		if ((s = q.top) != q.base &&
2377		U.getObjectVolatile
2378		(a, j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE) == t &&
#	Line 2363 | Line 2400 | public class ForkJoinPool extends Abstra
2400		*/
2401		static void externalHelpQuiescePool() {
2402		ForkJoinPool p; ForkJoinTask<?> t; WorkQueue q; int b;
2366	–	int r = ThreadLocalRandom.current().nextInt();
2403		if ((p = commonPool) != null &&
2404	<	(q = p.findNonEmptyStealQueue(r)) != null &&
2404	>	(q = p.findNonEmptyStealQueue(1)) != null &&
2405		(b = q.base) - q.top < 0 &&
2406		(t = q.pollAt(b)) != null)
2407		t.doExec();
#	Line 2442 | Line 2478 | public class ForkJoinPool extends Abstra
2478		throw new NullPointerException();
2479		if (parallelism <= 0 || parallelism > MAX_CAP)
2480		throw new IllegalArgumentException();
2445	–	this.parallelism = parallelism;
2481		this.factory = factory;
2482		this.ueh = handler;
2483	<	this.localMode = asyncMode ? FIFO_QUEUE : LIFO_QUEUE;
2483	>	this.config = parallelism | (asyncMode? (FIFO_QUEUE << 16) : 0);
2484		long np = (long)(-parallelism); // offset ctl counts
2485		this.ctl = ((np << AC_SHIFT) & AC_MASK) | ((np << TC_SHIFT) & TC_MASK);
2486		int pn = nextPoolId();
#	Line 2462 | Line 2497 | public class ForkJoinPool extends Abstra
2497		ForkJoinPool(int parallelism, long ctl,
2498		ForkJoinWorkerThreadFactory factory,
2499		Thread.UncaughtExceptionHandler handler) {
2500	<	this.parallelism = parallelism;
2500	>	this.config = parallelism;
2501		this.ctl = ctl;
2502		this.factory = factory;
2503		this.ueh = handler;
2469	–	this.localMode = LIFO_QUEUE;
2504		this.workerNamePrefix = "ForkJoinPool.commonPool-worker-";
2505		}
2506
#	Line 2476 | Line 2510 | public class ForkJoinPool extends Abstra
2510		* @return the common pool instance
2511		*/
2512		public static ForkJoinPool commonPool() {
2513	<	return commonPool; // cannot be null (if so, a static init error)
2513	>	// assert commonPool != null : "static init error";
2514	>	return commonPool;
2515		}
2516
2517		// Execution methods
#	Line 2648 | Line 2683 | public class ForkJoinPool extends Abstra
2683		* @return the targeted parallelism level of this pool
2684		*/
2685		public int getParallelism() {
2686	<	return parallelism;
2686	>	return config & SMASK;
2687		}
2688
2689		/**
#	Line 2669 | Line 2704 | public class ForkJoinPool extends Abstra
2704		* @return the number of worker threads
2705		*/
2706		public int getPoolSize() {
2707	<	return parallelism + (short)(ctl >>> TC_SHIFT);
2707	>	return (config & SMASK) + (short)(ctl >>> TC_SHIFT);
2708		}
2709
2710		/**
#	Line 2679 | Line 2714 | public class ForkJoinPool extends Abstra
2714		* @return {@code true} if this pool uses async mode
2715		*/
2716		public boolean getAsyncMode() {
2717	<	return localMode != 0;
2717	>	return (config >>> 16) == FIFO_QUEUE;
2718		}
2719
2720		/**
#	Line 2710 | Line 2745 | public class ForkJoinPool extends Abstra
2745		* @return the number of active threads
2746		*/
2747		public int getActiveThreadCount() {
2748	<	int r = parallelism + (int)(ctl >> AC_SHIFT);
2748	>	int r = (config & SMASK) + (int)(ctl >> AC_SHIFT);
2749		return (r <= 0) ? 0 : r; // suppress momentarily negative values
2750		}
2751
#	Line 2726 | Line 2761 | public class ForkJoinPool extends Abstra
2761		* @return {@code true} if all threads are currently idle
2762		*/
2763		public boolean isQuiescent() {
2764	<	return (int)(ctl >> AC_SHIFT) + parallelism == 0;
2764	>	return (int)(ctl >> AC_SHIFT) + (config & SMASK) == 0;
2765		}
2766
2767		/**
#	Line 2889 | Line 2924 | public class ForkJoinPool extends Abstra
2924		}
2925		}
2926		}
2927	<	int pc = parallelism;
2927	>	int pc = (config & SMASK);
2928		int tc = pc + (short)(c >>> TC_SHIFT);
2929		int ac = pc + (int)(c >> AC_SHIFT);
2930		if (ac < 0) // ignore transient negative
#	Line 2962 | Line 2997 | public class ForkJoinPool extends Abstra
2997		public boolean isTerminated() {
2998		long c = ctl;
2999		return ((c & STOP_BIT) != 0L &&
3000	<	(short)(c >>> TC_SHIFT) == -parallelism);
3000	>	(short)(c >>> TC_SHIFT) == -(config & SMASK));
3001		}
3002
3003		/**
#	Line 2981 | Line 3016 | public class ForkJoinPool extends Abstra
3016		public boolean isTerminating() {
3017		long c = ctl;
3018		return ((c & STOP_BIT) != 0L &&
3019	<	(short)(c >>> TC_SHIFT) != -parallelism);
3019	>	(short)(c >>> TC_SHIFT) != -(config & SMASK));
3020		}
3021
3022		/**
#	Line 3125 | Line 3160 | public class ForkJoinPool extends Abstra
3160		if (t instanceof ForkJoinWorkerThread) {
3161		ForkJoinPool p = ((ForkJoinWorkerThread)t).pool;
3162		while (!blocker.isReleasable()) { // variant of helpSignal
3163	<	WorkQueue[] ws; WorkQueue q; int m, n;
3163	>	WorkQueue[] ws; WorkQueue q; int m, n, u;
3164		if ((ws = p.workQueues) != null && (m = ws.length - 1) >= 0) {
3165		for (int i = 0; i <= m; ++i) {
3166		if (blocker.isReleasable())
3167		return;
3168		if ((q = ws[i]) != null && (n = q.queueSize()) > 0) {
3169		p.signalWork(q, n);
3170	<	if ((int)(p.ctl >> AC_SHIFT) >= 0)
3170	>	if ((u = (int)(p.ctl >>> 32)) >= 0 ||
3171	>	(u >> UAC_SHIFT) >= 0)
3172		break;
3173		}
3174		}
#	Line 3178 | Line 3214 | public class ForkJoinPool extends Abstra
3214		private static final long QLOCK;
3215
3216		static {
3181	–	// Establish common pool parameters
3182	–	// TBD: limit or report ignored exceptions?
3183	–
3184	–	int par = 0;
3185	–	ForkJoinWorkerThreadFactory fac = null;
3186	–	Thread.UncaughtExceptionHandler handler = null;
3187	–	try {
3188	–	String pp = System.getProperty(propPrefix + "parallelism");
3189	–	String hp = System.getProperty(propPrefix + "exceptionHandler");
3190	–	String fp = System.getProperty(propPrefix + "threadFactory");
3191	–	if (fp != null)
3192	–	fac = ((ForkJoinWorkerThreadFactory)ClassLoader.
3193	–	getSystemClassLoader().loadClass(fp).newInstance());
3194	–	if (hp != null)
3195	–	handler = ((Thread.UncaughtExceptionHandler)ClassLoader.
3196	–	getSystemClassLoader().loadClass(hp).newInstance());
3197	–	if (pp != null)
3198	–	par = Integer.parseInt(pp);
3199	–	} catch (Exception ignore) {
3200	–	}
3201	–
3217		int s; // initialize field offsets for CAS etc
3218		try {
3219		U = getUnsafe();
#	Line 3227 | Line 3242 | public class ForkJoinPool extends Abstra
3242		if ((s & (s-1)) != 0)
3243		throw new Error("data type scale not a power of two");
3244
3245	+	submitters = new ThreadLocal<Submitter>();
3246	+	ForkJoinWorkerThreadFactory fac = defaultForkJoinWorkerThreadFactory =
3247	+	new DefaultForkJoinWorkerThreadFactory();
3248		/*
3249	<	* For extra caution, computations to set up pool state are
3250	<	* here; the constructor just assigns these values to fields.
3249	>	* Establish common pool parameters.  For extra caution,
3250	>	* computations to set up common pool state are here; the
3251	>	* constructor just assigns these values to fields.
3252		*/
3253	<	ForkJoinWorkerThreadFactory defaultFac =
3254	<	defaultForkJoinWorkerThreadFactory =
3255	<	new DefaultForkJoinWorkerThreadFactory();
3256	<	if (fac == null)
3257	<	fac = defaultFac;
3253	>
3254	>	int par = 0;
3255	>	Thread.UncaughtExceptionHandler handler = null;
3256	>	try {  // TBD: limit or report ignored exceptions?
3257	>	String pp = System.getProperty
3258	>	("java.util.concurrent.ForkJoinPool.common.parallelism");
3259	>	String hp = System.getProperty
3260	>	("java.util.concurrent.ForkJoinPool.common.exceptionHandler");
3261	>	String fp = System.getProperty
3262	>	("java.util.concurrent.ForkJoinPool.common.threadFactory");
3263	>	if (fp != null)
3264	>	fac = ((ForkJoinWorkerThreadFactory)ClassLoader.
3265	>	getSystemClassLoader().loadClass(fp).newInstance());
3266	>	if (hp != null)
3267	>	handler = ((Thread.UncaughtExceptionHandler)ClassLoader.
3268	>	getSystemClassLoader().loadClass(hp).newInstance());
3269	>	if (pp != null)
3270	>	par = Integer.parseInt(pp);
3271	>	} catch (Exception ignore) {
3272	>	}
3273	>
3274		if (par <= 0)
3275		par = Runtime.getRuntime().availableProcessors();
3276		if (par > MAX_CAP)
3277		par = MAX_CAP;
3278	+	commonPoolParallelism = par;
3279		long np = (long)(-par); // precompute initial ctl value
3280		long ct = ((np << AC_SHIFT) & AC_MASK) | ((np << TC_SHIFT) & TC_MASK);
3281
3246	–	commonPoolParallelism = par;
3282		commonPool = new ForkJoinPool(par, ct, fac, handler);
3283		modifyThreadPermission = new RuntimePermission("modifyThread");
3249	–	submitters = new ThreadLocal<Submitter>();
3284		}
3285
3286		/**

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