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

Comparing jsr166/src/jsr166e/ForkJoinPool.java (file contents):
Revision 1.34 by dl, Mon Dec 17 16:31:08 2012 UTC vs.
Revision 1.56 by jsr166, Wed Feb 13 18:30:47 2013 UTC

#	Line 440 | Line 440 | public class ForkJoinPool extends Abstra
440		* Common Pool
441		* ===========
442		*
443	<	* The static commonPool always exists after static
443	>	* The static common Pool always exists after static
444		* initialization.  Since it (or any other created pool) need
445		* never be used, we minimize initial construction overhead and
446		* footprint to the setup of about a dozen fields, with no nested
#	Line 708 | Line 708 | public class ForkJoinPool extends Abstra
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
711	>	* @throws RejectedExecutionException if array cannot be resized
712		*/
713		final void push(ForkJoinTask<?> task) {
714		ForkJoinTask<?>[] a; ForkJoinPool p;
#	Line 907 | Line 907 | public class ForkJoinPool extends Abstra
907		* or any other cancelled task. Returns (true) on any CAS
908		* or consistency check failure so caller can retry.
909		*
910	<	* @return false if no progress can be made, else true;
910	>	* @return false if no progress can be made, else true
911		*/
912		final boolean tryRemoveAndExec(ForkJoinTask<?> task) {
913		boolean stat = true, removed = false, empty = true;
#	Line 952 | Line 952 | public class ForkJoinPool extends Abstra
952
953		/**
954		* Polls for and executes the given task or any other task in
955	<	* its CountedCompleter computation
955	>	* its CountedCompleter computation.
956		*/
957		final boolean pollAndExecCC(ForkJoinTask<?> root) {
958		ForkJoinTask<?>[] a; int b; Object o;
#	Line 1026 | Line 1026 | public class ForkJoinPool extends Abstra
1026		private static final int ABASE;
1027		private static final int ASHIFT;
1028		static {
1029	–	int s;
1029		try {
1030		U = getUnsafe();
1031		Class<?> k = WorkQueue.class;
#	Line 1034 | Line 1033 | public class ForkJoinPool extends Abstra
1033		QLOCK = U.objectFieldOffset
1034		(k.getDeclaredField("qlock"));
1035		ABASE = U.arrayBaseOffset(ak);
1036	<	s = U.arrayIndexScale(ak);
1036	>	int scale = U.arrayIndexScale(ak);
1037	>	if ((scale & (scale - 1)) != 0)
1038	>	throw new Error("data type scale not a power of two");
1039	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
1040		} catch (Exception e) {
1041		throw new Error(e);
1042		}
1041	–	if ((s & (s-1)) != 0)
1042	–	throw new Error("data type scale not a power of two");
1043	–	ASHIFT = 31 - Integer.numberOfLeadingZeros(s);
1043		}
1044		}
1045
#	Line 1074 | Line 1073 | public class ForkJoinPool extends Abstra
1073		* to paranoically avoid potential initialization circularities
1074		* as well as to simplify generated code.
1075		*/
1076	<	static final ForkJoinPool commonPool;
1076	>	static final ForkJoinPool common;
1077
1078		/**
1079	<	* Common pool parallelism. Must equal commonPool.parallelism.
1079	>	* Common pool parallelism. Must equal common.parallelism.
1080		*/
1081	<	static final int commonPoolParallelism;
1081	>	static final int commonParallelism;
1082
1083		/**
1084		* Sequence number for creating workerNamePrefix.
#	Line 1087 | Line 1086 | public class ForkJoinPool extends Abstra
1086		private static int poolNumberSequence;
1087
1088		/**
1089	<	* Return the next sequence number. We don't expect this to
1090	<	* ever contend so use simple builtin sync.
1089	>	* Returns the next sequence number. We don't expect this to
1090	>	* ever contend, so use simple builtin sync.
1091		*/
1092		private static final synchronized int nextPoolId() {
1093		return ++poolNumberSequence;
#	Line 1245 | Line 1244 | public class ForkJoinPool extends Abstra
1244		volatile Object pad10, pad11, pad12, pad13, pad14, pad15, pad16, pad17;
1245		volatile Object pad18, pad19, pad1a, pad1b;
1246
1247	<	/*
1247	>	/**
1248		* Acquires the plock lock to protect worker array and related
1249		* updates. This method is called only if an initial CAS on plock
1250	<	* fails. This acts as a spinLock for normal cases, but falls back
1250	>	* fails. This acts as a spinlock for normal cases, but falls back
1251		* to builtin monitor to block when (rarely) needed. This would be
1252		* a terrible idea for a highly contended lock, but works fine as
1253		* a more conservative alternative to a pure spinlock.
#	Line 1303 | Line 1302 | public class ForkJoinPool extends Abstra
1302		}
1303
1304		/**
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
1309	–	* optimistically allocate new array outside the lock and throw
1310	–	* away if (very rarely) not needed. (A similar tactic is used in
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 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	–	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) && 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	–	/**
1305		* Tries to create and start one worker if fewer than target
1306		* parallelism level exist. Adjusts counts etc on failure.
1307		*/
#	Line 1460 | Line 1426 | public class ForkJoinPool extends Abstra
1426		if (e > 0) {             // activate or create replacement
1427		if ((ws = workQueues) == null ||
1428		(i = e & SMASK) >= ws.length ||
1429	<	(v = ws[i]) != null)
1429	>	(v = ws[i]) == null)
1430		break;
1431		long nc = (((long)(v.nextWait & E_MASK)) |
1432		((long)(u + UAC_UNIT) << 32));
#	Line 1520 | Line 1486 | public class ForkJoinPool extends Abstra
1486		/**
1487		* Full version of externalPush. This method is called, among
1488		* other times, upon the first submission of the first task to the
1489	<	* pool, so must perform secondary initialization (via
1490	<	* initWorkers). It also detects first submission by an external
1491	<	* thread by looking up its ThreadLocal, and creates a new shared
1492	<	* queue if the one at index if empty or contended. The plock lock
1493	<	* body must be exception-free (so no try/finally) so we
1494	<	* optimistically allocate new queues outside the lock and throw
1495	<	* them away if (very rarely) not needed.
1489	>	* pool, so must perform secondary initialization.  It also
1490	>	* detects first submission by an external thread by looking up
1491	>	* its ThreadLocal, and creates a new shared queue if the one at
1492	>	* index if empty or contended. The plock lock body must be
1493	>	* exception-free (so no try/finally) so we optimistically
1494	>	* allocate new queues outside the lock and throw them away if
1495	>	* (very rarely) not needed.
1496	>	*
1497	>	* Secondary initialization occurs when plock is zero, to create
1498	>	* workQueue array and set plock to a valid value.  This lock body
1499	>	* must also be exception-free. Because the plock seq value can
1500	>	* eventually wrap around zero, this method harmlessly fails to
1501	>	* reinitialize if workQueues exists, while still advancing plock.
1502		*/
1503		private void fullExternalPush(ForkJoinTask<?> task) {
1504		int r = 0; // random index seed
#	Line 1537 | Line 1509 | public class ForkJoinPool extends Abstra
1509		r += SEED_INCREMENT) && r != 0)
1510		submitters.set(z = new Submitter(r));
1511		}
1512	<	else if (r == 0) {               // move to a different index
1512	>	else if (r == 0) {                  // move to a different index
1513		r = z.seed;
1514	<	r ^= r << 13;                // same xorshift as WorkQueues
1514	>	r ^= r << 13;                   // same xorshift as WorkQueues
1515		r ^= r >>> 17;
1516		z.seed = r ^ (r << 5);
1517		}
1518		else if ((ps = plock) < 0)
1519		throw new RejectedExecutionException();
1520		else if (ps == 0 || (ws = workQueues) == null ||
1521	<	(m = ws.length - 1) < 0)
1522	<	initWorkers();
1521	>	(m = ws.length - 1) < 0) { // initialize workQueues
1522	>	int p = config & SMASK;         // find power of two table size
1523	>	int n = (p > 1) ? p - 1 : 1;    // ensure at least 2 slots
1524	>	n |= n >>> 1; n |= n >>> 2;  n |= n >>> 4;
1525	>	n |= n >>> 8; n |= n >>> 16; n = (n + 1) << 1;
1526	>	WorkQueue[] nws = ((ws = workQueues) == null || ws.length == 0 ?
1527	>	new WorkQueue[n] : null);
1528	>	if (((ps = plock) & PL_LOCK) != 0 ||
1529	>	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
1530	>	ps = acquirePlock();
1531	>	if (((ws = workQueues) == null || ws.length == 0) && nws != null)
1532	>	workQueues = nws;
1533	>	int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN);
1534	>	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
1535	>	releasePlock(nps);
1536	>	}
1537		else if ((q = ws[k = r & m & SQMASK]) != null) {
1538		if (q.qlock == 0 && U.compareAndSwapInt(q, QLOCK, 0, 1)) {
1539		ForkJoinTask<?>[] a = q.array;
#	Line 1674 | Line 1660 | public class ForkJoinPool extends Abstra
1660		* park awaiting signal, else lingering to help scan and signal.
1661		*
1662		* * If a non-empty queue discovered or left as a hint,
1663	<	* help wake up other workers before return
1663	>	* help wake up other workers before return.
1664		*
1665		* @param w the worker (via its WorkQueue)
1666		* @return a task or null if none found
#	Line 1729 | Line 1715 | public class ForkJoinPool extends Abstra
1715		else if ((int)(c >> AC_SHIFT) == 1 - (config & SMASK))
1716		idleAwaitWork(w, nc, c);
1717		}
1718	<	else if (w.eventCount < 0 && !tryTerminate(false, false) &&
1733	<	ctl == c) {         // block
1718	>	else if (w.eventCount < 0 && ctl == c) {
1719		Thread wt = Thread.currentThread();
1720		Thread.interrupted();    // clear status
1721		U.putObject(wt, PARKBLOCKER, this);
1722		w.parker = wt;           // emulate LockSupport.park
1723		if (w.eventCount < 0)    // recheck
1724	<	U.park(false, 0L);
1724	>	U.park(false, 0L);   // block
1725		w.parker = null;
1726		U.putObject(wt, PARKBLOCKER, null);
1727		}
#	Line 1745 | Line 1730 | public class ForkJoinPool extends Abstra
1730		(ws = workQueues) != null && h < ws.length &&
1731		(q = ws[h]) != null) {      // signal others before retry
1732		WorkQueue v; Thread p; int u, i, s;
1733	<	for (int n = (config & SMASK) >>> 1;;) {
1733	>	for (int n = (config & SMASK) - 1;;) {
1734		int idleCount = (w.eventCount < 0) ? 0 : -1;
1735		if (((s = idleCount - q.base + q.top) <= n &&
1736		(n = s) <= 0) ||
#	Line 1785 | Line 1770 | public class ForkJoinPool extends Abstra
1770		*/
1771		private void idleAwaitWork(WorkQueue w, long currentCtl, long prevCtl) {
1772		if (w != null && w.eventCount < 0 &&
1773	<	!tryTerminate(false, false) && (int)prevCtl != 0) {
1773	>	!tryTerminate(false, false) && (int)prevCtl != 0 &&
1774	>	ctl == currentCtl) {
1775		int dc = -(short)(currentCtl >>> TC_SHIFT);
1776		long parkTime = dc < 0 ? FAST_IDLE_TIMEOUT: (dc + 1) * IDLE_TIMEOUT;
1777		long deadline = System.nanoTime() + parkTime - TIMEOUT_SLOP;
#	Line 1803 | Line 1789 | public class ForkJoinPool extends Abstra
1789		if (deadline - System.nanoTime() <= 0L &&
1790		U.compareAndSwapLong(this, CTL, currentCtl, prevCtl)) {
1791		w.eventCount = (w.eventCount + E_SEQ) | E_MASK;
1792	+	w.hint = -1;
1793		w.qlock = -1;   // shrink
1794		break;
1795		}
#	Line 1944 | Line 1931 | public class ForkJoinPool extends Abstra
1931		* @param task the task to join
1932		* @param mode if shared, exit upon completing any task
1933		* if all workers are active
1947	–	*
1934		*/
1935		private int helpComplete(ForkJoinTask<?> task, int mode) {
1936		WorkQueue[] ws; WorkQueue q; int m, n, s, u;
#	Line 2096 | Line 2082 | public class ForkJoinPool extends Abstra
2082
2083		/**
2084		* Returns a (probably) non-empty steal queue, if one is found
2085	<	* during a random, then cyclic scan, else null.  This method must
2086	<	* be retried by caller if, by the time it tries to use the queue,
2101	<	* it is empty.
2085	>	* during a scan, else null.  This method must be retried by
2086	>	* caller if, by the time it tries to use the queue, it is empty.
2087		* @param r a (random) seed for scanning
2088		*/
2089		private WorkQueue findNonEmptyStealQueue(int r) {
2090	<	for (WorkQueue[] ws;;) {
2091	<	int ps = plock, m, n;
2092	<	if ((ws = workQueues) == null || (m = ws.length - 1) < 1)
2093	<	return null;
2094	<	for (int j = (m + 1) << 2; ;) {
2095	<	WorkQueue q = ws[(((r + j) << 1) | 1) & m];
2096	<	if (q != null && (n = q.base - q.top) < 0) {
2112	<	if (n < -1)
2113	<	signalWork(q);
2114	<	return q;
2115	<	}
2116	<	else if (--j < 0) {
2117	<	if (plock == ps)
2118	<	return null;
2119	<	break;
2090	>	for (;;) {
2091	>	int ps = plock, m; WorkQueue[] ws; WorkQueue q;
2092	>	if ((ws = workQueues) != null && (m = ws.length - 1) >= 0) {
2093	>	for (int j = (m + 1) << 2; j >= 0; --j) {
2094	>	if ((q = ws[(((r + j) << 1) | 1) & m]) != null &&
2095	>	q.base - q.top < 0)
2096	>	return q;
2097		}
2098		}
2099	+	if (plock == ps)
2100	+	return null;
2101		}
2102		}
2103
#	Line 2130 | Line 2109 | public class ForkJoinPool extends Abstra
2109		*/
2110		final void helpQuiescePool(WorkQueue w) {
2111		for (boolean active = true;;) {
2112	<	ForkJoinTask<?> localTask; // exhaust local queue
2113	<	while ((localTask = w.nextLocalTask()) != null)
2114	<	localTask.doExec();
2115	<	// Similar to loop in scan(), but ignoring submissions
2116	<	WorkQueue q = findNonEmptyStealQueue(w.nextSeed());
2117	<	if (q != null) {
2118	<	ForkJoinTask<?> t; int b;
2112	>	long c; WorkQueue q; ForkJoinTask<?> t; int b;
2113	>	while ((t = w.nextLocalTask()) != null) {
2114	>	if (w.base - w.top < 0)
2115	>	signalWork(w);
2116	>	t.doExec();
2117	>	}
2118	>	if ((q = findNonEmptyStealQueue(w.nextSeed())) != null) {
2119		if (!active) {      // re-establish active count
2141	–	long c;
2120		active = true;
2121		do {} while (!U.compareAndSwapLong
2122		(this, CTL, c = ctl, c + AC_UNIT));
2123		}
2124	<	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null)
2124	>	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null) {
2125	>	if (q.base - q.top < 0)
2126	>	signalWork(q);
2127		w.runSubtask(t);
2128	+	}
2129		}
2130	<	else {
2131	<	long c;
2132	<	if (active) {       // decrement active count without queuing
2130	>	else if (active) {       // decrement active count without queuing
2131	>	long nc = (c = ctl) - AC_UNIT;
2132	>	if ((int)(nc >> AC_SHIFT) + (config & SMASK) == 0)
2133	>	return;          // bypass decrement-then-increment
2134	>	if (U.compareAndSwapLong(this, CTL, c, nc))
2135		active = false;
2153	–	do {} while (!U.compareAndSwapLong
2154	–	(this, CTL, c = ctl, c -= AC_UNIT));
2155	–	}
2156	–	else
2157	–	c = ctl;        // re-increment on exit
2158	–	if ((int)(c >> AC_SHIFT) + (config & SMASK) == 0) {
2159	–	do {} while (!U.compareAndSwapLong
2160	–	(this, CTL, c = ctl, c + AC_UNIT));
2161	–	break;
2162	–	}
2136		}
2137	+	else if ((int)((c = ctl) >> AC_SHIFT) + (config & SMASK) == 0 &&
2138	+	U.compareAndSwapLong(this, CTL, c, c + AC_UNIT))
2139	+	return;
2140		}
2141		}
2142
#	Line 2176 | Line 2152 | public class ForkJoinPool extends Abstra
2152		return t;
2153		if ((q = findNonEmptyStealQueue(w.nextSeed())) == null)
2154		return null;
2155	<	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null)
2155	>	if ((b = q.base) - q.top < 0 && (t = q.pollAt(b)) != null) {
2156	>	if (q.base - q.top < 0)
2157	>	signalWork(q);
2158		return t;
2159	+	}
2160		}
2161		}
2162
#	Line 2206 | Line 2185 | public class ForkJoinPool extends Abstra
2185		* producing extra tasks amortizes the uncertainty of progress and
2186		* diffusion assumptions.
2187		*
2188	<	* So, users will want to use values larger, but not much larger
2188	>	* So, users will want to use values larger (but not much larger)
2189		* than 1 to both smooth over transient shortages and hedge
2190		* against uneven progress; as traded off against the cost of
2191		* extra task overhead. We leave the user to pick a threshold
#	Line 2259 | Line 2238 | public class ForkJoinPool extends Abstra
2238		* @return true if now terminating or terminated
2239		*/
2240		private boolean tryTerminate(boolean now, boolean enable) {
2241	<	if (this == commonPool)                     // cannot shut down
2241	>	int ps;
2242	>	if (this == common)                    // cannot shut down
2243		return false;
2244	+	if ((ps = plock) >= 0) {                   // enable by setting plock
2245	+	if (!enable)
2246	+	return false;
2247	+	if ((ps & PL_LOCK) != 0 ||
2248	+	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
2249	+	ps = acquirePlock();
2250	+	int nps = ((ps + PL_LOCK) & ~SHUTDOWN) | SHUTDOWN;
2251	+	if (!U.compareAndSwapInt(this, PLOCK, ps, nps))
2252	+	releasePlock(nps);
2253	+	}
2254		for (long c;;) {
2255	<	if (((c = ctl) & STOP_BIT) != 0) {      // already terminating
2255	>	if (((c = ctl) & STOP_BIT) != 0) {     // already terminating
2256		if ((short)(c >>> TC_SHIFT) == -(config & SMASK)) {
2257		synchronized (this) {
2258	<	notifyAll();                // signal when 0 workers
2258	>	notifyAll();               // signal when 0 workers
2259		}
2260		}
2261		return true;
2262		}
2263	<	if (plock >= 0) {                       // not yet enabled
2264	<	int ps;
2265	<	if (!enable)
2263	>	if (!now) {                            // check if idle & no tasks
2264	>	WorkQueue[] ws; WorkQueue w;
2265	>	if ((int)(c >> AC_SHIFT) != -(config & SMASK))
2266		return false;
2267	<	if (((ps = plock) & PL_LOCK) != 0 ||
2268	<	!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK))
2269	<	ps = acquirePlock();
2270	<	if (!U.compareAndSwapInt(this, PLOCK, ps, SHUTDOWN))
2271	<	releasePlock(SHUTDOWN);
2272	<	}
2273	<	if (!now) {                             // check if idle & no tasks
2274	<	if ((int)(c >> AC_SHIFT) != -(config & SMASK) ||
2275	<	hasQueuedSubmissions())
2276	<	return false;
2287	<	// Check for unqueued inactive workers. One pass suffices.
2288	<	WorkQueue[] ws = workQueues; WorkQueue w;
2289	<	if (ws != null) {
2290	<	for (int i = 1; i < ws.length; i += 2) {
2291	<	if ((w = ws[i]) != null && w.eventCount >= 0)
2292	<	return false;
2267	>	if ((ws = workQueues) != null) {
2268	>	for (int i = 0; i < ws.length; ++i) {
2269	>	if ((w = ws[i]) != null) {
2270	>	if (!w.isEmpty()) {    // signal unprocessed tasks
2271	>	signalWork(w);
2272	>	return false;
2273	>	}
2274	>	if ((i & 1) != 0 && w.eventCount >= 0)
2275	>	return false;      // unqueued inactive worker
2276	>	}
2277		}
2278		}
2279		}
2280		if (U.compareAndSwapLong(this, CTL, c, c | STOP_BIT)) {
2281		for (int pass = 0; pass < 3; ++pass) {
2282	<	WorkQueue[] ws = workQueues;
2283	<	if (ws != null) {
2300	<	WorkQueue w; Thread wt;
2282	>	WorkQueue[] ws; WorkQueue w; Thread wt;
2283	>	if ((ws = workQueues) != null) {
2284		int n = ws.length;
2285		for (int i = 0; i < n; ++i) {
2286		if ((w = ws[i]) != null) {
#	Line 2308 | Line 2291 | public class ForkJoinPool extends Abstra
2291		if (!wt.isInterrupted()) {
2292		try {
2293		wt.interrupt();
2294	<	} catch (SecurityException ignore) {
2294	>	} catch (Throwable ignore) {
2295		}
2296		}
2297		U.unpark(wt);
#	Line 2319 | Line 2302 | public class ForkJoinPool extends Abstra
2302		// Wake up workers parked on event queue
2303		int i, e; long cc; Thread p;
2304		while ((e = (int)(cc = ctl) & E_MASK) != 0 &&
2305	<	(i = e & SMASK) < n &&
2305	>	(i = e & SMASK) < n && i >= 0 &&
2306		(w = ws[i]) != null) {
2307		long nc = ((long)(w.nextWait & E_MASK) |
2308		((cc + AC_UNIT) & AC_MASK) |
#	Line 2347 | Line 2330 | public class ForkJoinPool extends Abstra
2330		static WorkQueue commonSubmitterQueue() {
2331		ForkJoinPool p; WorkQueue[] ws; int m; Submitter z;
2332		return ((z = submitters.get()) != null &&
2333	<	(p = commonPool) != null &&
2333	>	(p = common) != null &&
2334		(ws = p.workQueues) != null &&
2335		(m = ws.length - 1) >= 0) ?
2336		ws[m & z.seed & SQMASK] : null;
#	Line 2361 | Line 2344 | public class ForkJoinPool extends Abstra
2344		ForkJoinTask<?>[] a;  int m, s;
2345		if (t != null &&
2346		(z = submitters.get()) != null &&
2347	<	(p = commonPool) != null &&
2347	>	(p = common) != null &&
2348		(ws = p.workQueues) != null &&
2349		(m = ws.length - 1) >= 0 &&
2350		(q = ws[m & z.seed & SQMASK]) != null &&
#	Line 2438 | Line 2421 | public class ForkJoinPool extends Abstra
2421		ForkJoinTask<?>[] a;  int m, s, n;
2422		if (t != null &&
2423		(z = submitters.get()) != null &&
2424	<	(p = commonPool) != null &&
2424	>	(p = common) != null &&
2425		(ws = p.workQueues) != null &&
2426		(m = ws.length - 1) >= 0 &&
2427		(q = ws[m & z.seed & SQMASK]) != null &&
#	Line 2467 | Line 2450 | public class ForkJoinPool extends Abstra
2450		}
2451		}
2452
2470	–	/**
2471	–	* Restricted version of helpQuiescePool for external callers
2472	–	*/
2473	–	static void externalHelpQuiescePool() {
2474	–	ForkJoinPool p; ForkJoinTask<?> t; WorkQueue q; int b;
2475	–	if ((p = commonPool) != null &&
2476	–	(q = p.findNonEmptyStealQueue(1)) != null &&
2477	–	(b = q.base) - q.top < 0 &&
2478	–	(t = q.pollAt(b)) != null)
2479	–	t.doExec();
2480	–	}
2481	–
2453		// Exported methods
2454
2455		// Constructors
#	Line 2495 | Line 2466 | public class ForkJoinPool extends Abstra
2466		*         java.lang.RuntimePermission}{@code ("modifyThread")}
2467		*/
2468		public ForkJoinPool() {
2469	<	this(Runtime.getRuntime().availableProcessors(),
2469	>	this(Math.min(MAX_CAP, Runtime.getRuntime().availableProcessors()),
2470		defaultForkJoinWorkerThreadFactory, null, false);
2471		}
2472
#	Line 2578 | Line 2549 | public class ForkJoinPool extends Abstra
2549
2550		/**
2551		* Returns the common pool instance. This pool is statically
2552	<	* constructed; its run state is unaffected by attempts to
2553	<	* {@link @shutdown} or {@link #shutdownNow}.
2552	>	* constructed; its run state is unaffected by attempts to {@link
2553	>	* #shutdown} or {@link #shutdownNow}. However this pool and any
2554	>	* ongoing processing are automatically terminated upon program
2555	>	* {@link System#exit}.  Any program that relies on asynchronous
2556	>	* task processing to complete before program termination should
2557	>	* invoke {@code commonPool().}{@link #awaitQuiescence}, before
2558	>	* exit.
2559		*
2560		* @return the common pool instance
2561	+	* @since 1.8
2562		*/
2563		public static ForkJoinPool commonPool() {
2564	<	// assert commonPool != null : "static init error";
2565	<	return commonPool;
2564	>	// assert common != null : "static init error";
2565	>	return common;
2566		}
2567
2568		// Execution methods
#	Line 2708 | Line 2685 | public class ForkJoinPool extends Abstra
2685		// In previous versions of this class, this method constructed
2686		// a task to run ForkJoinTask.invokeAll, but now external
2687		// invocation of multiple tasks is at least as efficient.
2688	<	List<ForkJoinTask<T>> fs = new ArrayList<ForkJoinTask<T>>(tasks.size());
2712	<	// Workaround needed because method wasn't declared with
2713	<	// wildcards in return type but should have been.
2714	<	@SuppressWarnings({"unchecked", "rawtypes"})
2715	<	List<Future<T>> futures = (List<Future<T>>) (List) fs;
2688	>	ArrayList<Future<T>> futures = new ArrayList<Future<T>>(tasks.size());
2689
2690		boolean done = false;
2691		try {
2692		for (Callable<T> t : tasks) {
2693		ForkJoinTask<T> f = new ForkJoinTask.AdaptedCallable<T>(t);
2694	+	futures.add(f);
2695		externalPush(f);
2722	–	fs.add(f);
2696		}
2697	<	for (ForkJoinTask<T> f : fs)
2698	<	f.quietlyJoin();
2697	>	for (int i = 0, size = futures.size(); i < size; i++)
2698	>	((ForkJoinTask<?>)futures.get(i)).quietlyJoin();
2699		done = true;
2700		return futures;
2701		} finally {
2702		if (!done)
2703	<	for (ForkJoinTask<T> f : fs)
2704	<	f.cancel(false);
2703	>	for (int i = 0, size = futures.size(); i < size; i++)
2704	>	futures.get(i).cancel(false);
2705		}
2706		}
2707
#	Line 2764 | Line 2737 | public class ForkJoinPool extends Abstra
2737		* Returns the targeted parallelism level of the common pool.
2738		*
2739		* @return the targeted parallelism level of the common pool
2740	+	* @since 1.8
2741		*/
2742		public static int getCommonPoolParallelism() {
2743	<	return commonPoolParallelism;
2743	>	return commonParallelism;
2744		}
2745
2746		/**
#	Line 3024 | Line 2998 | public class ForkJoinPool extends Abstra
2998		* Possibly initiates an orderly shutdown in which previously
2999		* submitted tasks are executed, but no new tasks will be
3000		* accepted. Invocation has no effect on execution state if this
3001	<	* is the {@link #commonPool}, and no additional effect if
3001	>	* is the {@link #commonPool()}, and no additional effect if
3002		* already shut down.  Tasks that are in the process of being
3003		* submitted concurrently during the course of this method may or
3004		* may not be rejected.
#	Line 3042 | Line 3016 | public class ForkJoinPool extends Abstra
3016		/**
3017		* Possibly attempts to cancel and/or stop all tasks, and reject
3018		* all subsequently submitted tasks.  Invocation has no effect on
3019	<	* execution state if this is the {@link #commonPool}, and no
3019	>	* execution state if this is the {@link #commonPool()}, and no
3020		* additional effect if already shut down. Otherwise, tasks that
3021		* are in the process of being submitted or executed concurrently
3022		* during the course of this method may or may not be
#	Line 3105 | Line 3079 | public class ForkJoinPool extends Abstra
3079		/**
3080		* Blocks until all tasks have completed execution after a
3081		* shutdown request, or the timeout occurs, or the current thread
3082	<	* is interrupted, whichever happens first. Note that the {@link
3083	<	* #commonPool()} never terminates until program shutdown so
3084	<	* this method will always time out.
3082	>	* is interrupted, whichever happens first. Because the {@link
3083	>	* #commonPool()} never terminates until program shutdown, when
3084	>	* applied to the common pool, this method is equivalent to {@link
3085	>	* #awaitQuiescence} but always returns {@code false}.
3086		*
3087		* @param timeout the maximum time to wait
3088		* @param unit the time unit of the timeout argument
#	Line 3117 | Line 3092 | public class ForkJoinPool extends Abstra
3092		*/
3093		public boolean awaitTermination(long timeout, TimeUnit unit)
3094		throws InterruptedException {
3095	+	if (Thread.interrupted())
3096	+	throw new InterruptedException();
3097	+	if (this == common) {
3098	+	awaitQuiescence(timeout, unit);
3099	+	return false;
3100	+	}
3101		long nanos = unit.toNanos(timeout);
3102		if (isTerminated())
3103		return true;
#	Line 3136 | Line 3117 | public class ForkJoinPool extends Abstra
3117		}
3118
3119		/**
3120	+	* If called by a ForkJoinTask operating in this pool, equivalent
3121	+	* in effect to {@link ForkJoinTask#helpQuiesce}. Otherwise,
3122	+	* waits and/or attempts to assist performing tasks until this
3123	+	* pool {@link #isQuiescent} or the indicated timeout elapses.
3124	+	*
3125	+	* @param timeout the maximum time to wait
3126	+	* @param unit the time unit of the timeout argument
3127	+	* @return {@code true} if quiescent; {@code false} if the
3128	+	* timeout elapsed.
3129	+	*/
3130	+	public boolean awaitQuiescence(long timeout, TimeUnit unit) {
3131	+	long nanos = unit.toNanos(timeout);
3132	+	ForkJoinWorkerThread wt;
3133	+	Thread thread = Thread.currentThread();
3134	+	if ((thread instanceof ForkJoinWorkerThread) &&
3135	+	(wt = (ForkJoinWorkerThread)thread).pool == this) {
3136	+	helpQuiescePool(wt.workQueue);
3137	+	return true;
3138	+	}
3139	+	long startTime = System.nanoTime();
3140	+	WorkQueue[] ws;
3141	+	int r = 0, m;
3142	+	boolean found = true;
3143	+	while (!isQuiescent() && (ws = workQueues) != null &&
3144	+	(m = ws.length - 1) >= 0) {
3145	+	if (!found) {
3146	+	if ((System.nanoTime() - startTime) > nanos)
3147	+	return false;
3148	+	Thread.yield(); // cannot block
3149	+	}
3150	+	found = false;
3151	+	for (int j = (m + 1) << 2; j >= 0; --j) {
3152	+	ForkJoinTask<?> t; WorkQueue q; int b;
3153	+	if ((q = ws[r++ & m]) != null && (b = q.base) - q.top < 0) {
3154	+	found = true;
3155	+	if ((t = q.pollAt(b)) != null) {
3156	+	if (q.base - q.top < 0)
3157	+	signalWork(q);
3158	+	t.doExec();
3159	+	}
3160	+	break;
3161	+	}
3162	+	}
3163	+	}
3164	+	return true;
3165	+	}
3166	+
3167	+	/**
3168	+	* Waits and/or attempts to assist performing tasks indefinitely
3169	+	* until the {@link #commonPool()} {@link #isQuiescent}.
3170	+	*/
3171	+	static void quiesceCommonPool() {
3172	+	common.awaitQuiescence(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
3173	+	}
3174	+
3175	+	/**
3176		* Interface for extending managed parallelism for tasks running
3177		* in {@link ForkJoinPool}s.
3178		*
#	Line 3288 | Line 3325 | public class ForkJoinPool extends Abstra
3325		private static final long QLOCK;
3326
3327		static {
3328	<	int s; // initialize field offsets for CAS etc
3328	>	// initialize field offsets for CAS etc
3329		try {
3330		U = getUnsafe();
3331		Class<?> k = ForkJoinPool.class;
#	Line 3308 | Line 3345 | public class ForkJoinPool extends Abstra
3345		(wk.getDeclaredField("qlock"));
3346		Class<?> ak = ForkJoinTask[].class;
3347		ABASE = U.arrayBaseOffset(ak);
3348	<	s = U.arrayIndexScale(ak);
3349	<	ASHIFT = 31 - Integer.numberOfLeadingZeros(s);
3348	>	int scale = U.arrayIndexScale(ak);
3349	>	if ((scale & (scale - 1)) != 0)
3350	>	throw new Error("data type scale not a power of two");
3351	>	ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
3352		} catch (Exception e) {
3353		throw new Error(e);
3354		}
3316	–	if ((s & (s-1)) != 0)
3317	–	throw new Error("data type scale not a power of two");
3355
3356		submitters = new ThreadLocal<Submitter>();
3357		ForkJoinWorkerThreadFactory fac = defaultForkJoinWorkerThreadFactory =
#	Line 3351 | Line 3388 | public class ForkJoinPool extends Abstra
3388		par = Runtime.getRuntime().availableProcessors();
3389		if (par > MAX_CAP)
3390		par = MAX_CAP;
3391	<	commonPoolParallelism = par;
3391	>	commonParallelism = par;
3392		long np = (long)(-par); // precompute initial ctl value
3393		long ct = ((np << AC_SHIFT) & AC_MASK) | ((np << TC_SHIFT) & TC_MASK);
3394
3395	<	commonPool = new ForkJoinPool(par, ct, fac, handler);
3395	>	common = new ForkJoinPool(par, ct, fac, handler);
3396		}
3397
3398		/**
#	Line 3368 | Line 3405 | public class ForkJoinPool extends Abstra
3405		private static sun.misc.Unsafe getUnsafe() {
3406		try {
3407		return sun.misc.Unsafe.getUnsafe();
3408	<	} catch (SecurityException se) {
3409	<	try {
3410	<	return java.security.AccessController.doPrivileged
3411	<	(new java.security
3412	<	.PrivilegedExceptionAction<sun.misc.Unsafe>() {
3413	<	public sun.misc.Unsafe run() throws Exception {
3414	<	java.lang.reflect.Field f = sun.misc
3415	<	.Unsafe.class.getDeclaredField("theUnsafe");
3416	<	f.setAccessible(true);
3417	<	return (sun.misc.Unsafe) f.get(null);
3418	<	}});
3419	<	} catch (java.security.PrivilegedActionException e) {
3420	<	throw new RuntimeException("Could not initialize intrinsics",
3421	<	e.getCause());
3422	<	}
3408	>	} catch (SecurityException tryReflectionInstead) {}
3409	>	try {
3410	>	return java.security.AccessController.doPrivileged
3411	>	(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
3412	>	public sun.misc.Unsafe run() throws Exception {
3413	>	Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class;
3414	>	for (java.lang.reflect.Field f : k.getDeclaredFields()) {
3415	>	f.setAccessible(true);
3416	>	Object x = f.get(null);
3417	>	if (k.isInstance(x))
3418	>	return k.cast(x);
3419	>	}
3420	>	throw new NoSuchFieldError("the Unsafe");
3421	>	}});
3422	>	} catch (java.security.PrivilegedActionException e) {
3423	>	throw new RuntimeException("Could not initialize intrinsics",
3424	>	e.getCause());
3425		}
3426		}
3388	–
3427		}

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