51 |
|
* dynamically adding, suspending, or resuming internal worker |
52 |
|
* threads, even if some tasks are stalled waiting to join |
53 |
|
* others. However, no such adjustments are guaranteed in the face of |
54 |
< |
* blocked IO or other unmanaged synchronization. The nested {@link |
54 |
> |
* blocked I/O or other unmanaged synchronization. The nested {@link |
55 |
|
* ManagedBlocker} interface enables extension of the kinds of |
56 |
|
* synchronization accommodated. |
57 |
|
* |
99 |
|
* |
100 |
|
* <p>The common pool is by default constructed with default |
101 |
|
* parameters, but these may be controlled by setting three {@link |
102 |
< |
* System#getProperty properties} with prefix {@code |
102 |
> |
* System#getProperty system properties} with prefix {@code |
103 |
|
* java.util.concurrent.ForkJoinPool.common}: {@code parallelism} -- |
104 |
|
* an integer greater than zero, {@code threadFactory} -- the class |
105 |
|
* name of a {@link ForkJoinWorkerThreadFactory}, and {@code |
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 |
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; |
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; |
987 |
|
if (t != null) { |
988 |
|
(currentSteal = t).doExec(); |
989 |
|
currentSteal = null; |
990 |
+ |
++nsteals; |
991 |
|
if (base - top < 0) { // process remaining local tasks |
992 |
|
if (mode == 0) |
993 |
|
popAndExecAll(); |
994 |
|
else |
995 |
|
pollAndExecAll(); |
996 |
|
} |
996 |
– |
++nsteals; |
997 |
– |
hint = -1; |
997 |
|
} |
998 |
|
} |
999 |
|
|
1020 |
|
s != Thread.State.TIMED_WAITING); |
1021 |
|
} |
1022 |
|
|
1024 |
– |
/** |
1025 |
– |
* If this owned and is not already interrupted, try to |
1026 |
– |
* interrupt and/or unpark, ignoring exceptions. |
1027 |
– |
*/ |
1028 |
– |
final void interruptOwner() { |
1029 |
– |
Thread wt, p; |
1030 |
– |
if ((wt = owner) != null && !wt.isInterrupted()) { |
1031 |
– |
try { |
1032 |
– |
wt.interrupt(); |
1033 |
– |
} catch (SecurityException ignore) { |
1034 |
– |
} |
1035 |
– |
} |
1036 |
– |
if ((p = parker) != null) |
1037 |
– |
U.unpark(p); |
1038 |
– |
} |
1039 |
– |
|
1023 |
|
// Unsafe mechanics |
1024 |
|
private static final sun.misc.Unsafe U; |
1025 |
|
private static final long QLOCK; |
1026 |
|
private static final int ABASE; |
1027 |
|
private static final int ASHIFT; |
1028 |
|
static { |
1046 |
– |
int s; |
1029 |
|
try { |
1030 |
|
U = getUnsafe(); |
1031 |
|
Class<?> k = WorkQueue.class; |
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 |
|
} |
1058 |
– |
if ((s & (s-1)) != 0) |
1059 |
– |
throw new Error("data type scale not a power of two"); |
1060 |
– |
ASHIFT = 31 - Integer.numberOfLeadingZeros(s); |
1043 |
|
} |
1044 |
|
} |
1045 |
|
|
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. |
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; |
1111 |
|
private static final long FAST_IDLE_TIMEOUT = 200L * 1000L * 1000L; |
1112 |
|
|
1113 |
|
/** |
1114 |
+ |
* Tolerance for idle timeouts, to cope with timer undershoots |
1115 |
+ |
*/ |
1116 |
+ |
private static final long TIMEOUT_SLOP = 2000000L; |
1117 |
+ |
|
1118 |
+ |
/** |
1119 |
|
* The maximum stolen->joining link depth allowed in method |
1120 |
|
* tryHelpStealer. Must be a power of two. Depths for legitimate |
1121 |
|
* chains are unbounded, but we use a fixed constant to avoid |
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. See |
1267 |
< |
* internal ConcurrentHashMap documentation for further |
1268 |
< |
* explanation of nearly the same construction. |
1253 |
> |
* a more conservative alternative to a pure spinlock. |
1254 |
|
*/ |
1255 |
|
private int acquirePlock() { |
1256 |
|
int spins = PL_SPINS, r = 0, ps, nps; |
1302 |
|
} |
1303 |
|
|
1304 |
|
/** |
1305 |
< |
* Performs secondary initialization, called when plock is zero. |
1306 |
< |
* Creates workQueue array and sets plock to a valid value. The |
1322 |
< |
* lock body must be exception-free (so no try/finally) so we |
1323 |
< |
* optimistically allocate new array outside the lock and throw |
1324 |
< |
* away if (very rarely) not needed. (A similar tactic is used in |
1325 |
< |
* fullExternalPush.) Because the plock seq value can eventually |
1326 |
< |
* wrap around zero, this method harmlessly fails to reinitialize |
1327 |
< |
* if workQueues exists, while still advancing plock. |
1328 |
< |
* |
1329 |
< |
* Additonally tries to create the first worker. |
1330 |
< |
*/ |
1331 |
< |
private void initWorkers() { |
1332 |
< |
WorkQueue[] ws, nws; int ps; |
1333 |
< |
int p = config & SMASK; // find power of two table size |
1334 |
< |
int n = (p > 1) ? p - 1 : 1; // ensure at least 2 slots |
1335 |
< |
n |= n >>> 1; n |= n >>> 2; n |= n >>> 4; n |= n >>> 8; n |= n >>> 16; |
1336 |
< |
n = (n + 1) << 1; |
1337 |
< |
if ((ws = workQueues) == null || ws.length == 0) |
1338 |
< |
nws = new WorkQueue[n]; |
1339 |
< |
else |
1340 |
< |
nws = null; |
1341 |
< |
if (((ps = plock) & PL_LOCK) != 0 || |
1342 |
< |
!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK)) |
1343 |
< |
ps = acquirePlock(); |
1344 |
< |
if (((ws = workQueues) == null || ws.length == 0) && nws != null) |
1345 |
< |
workQueues = nws; |
1346 |
< |
int nps = (ps & SHUTDOWN) | ((ps + PL_LOCK) & ~SHUTDOWN); |
1347 |
< |
if (!U.compareAndSwapInt(this, PLOCK, ps, nps)) |
1348 |
< |
releasePlock(nps); |
1349 |
< |
tryAddWorker(); |
1350 |
< |
} |
1351 |
< |
|
1352 |
< |
/** |
1353 |
< |
* Tries to create and start one worker. Adjusts counts etc on |
1354 |
< |
* failure. |
1305 |
> |
* Tries to create and start one worker if fewer than target |
1306 |
> |
* parallelism level exist. Adjusts counts etc on failure. |
1307 |
|
*/ |
1308 |
|
private void tryAddWorker() { |
1309 |
|
long c; int u; |
1413 |
|
} |
1414 |
|
} |
1415 |
|
|
1416 |
< |
long c; // adjust ctl counts |
1416 |
> |
long c; // adjust ctl counts |
1417 |
|
do {} while (!U.compareAndSwapLong |
1418 |
|
(this, CTL, c = ctl, (((c - AC_UNIT) & AC_MASK) | |
1419 |
|
((c - TC_UNIT) & TC_MASK) | |
1420 |
|
(c & ~(AC_MASK|TC_MASK))))); |
1421 |
|
|
1422 |
< |
if (!tryTerminate(false, false) && w != null) { |
1423 |
< |
w.cancelAll(); // cancel remaining tasks |
1424 |
< |
if (w.array != null) // suppress signal if never ran |
1425 |
< |
tryAddWorker(); // create replacement |
1426 |
< |
if (ex == null) // help clean refs on way out |
1427 |
< |
ForkJoinTask.helpExpungeStaleExceptions(); |
1422 |
> |
if (!tryTerminate(false, false) && w != null && w.array != null) { |
1423 |
> |
w.cancelAll(); // cancel remaining tasks |
1424 |
> |
WorkQueue[] ws; WorkQueue v; Thread p; int u, i, e; |
1425 |
> |
while ((u = (int)((c = ctl) >>> 32)) < 0 && (e = (int)c) >= 0) { |
1426 |
> |
if (e > 0) { // activate or create replacement |
1427 |
> |
if ((ws = workQueues) == null || |
1428 |
> |
(i = e & SMASK) >= ws.length || |
1429 |
> |
(v = ws[i]) == null) |
1430 |
> |
break; |
1431 |
> |
long nc = (((long)(v.nextWait & E_MASK)) | |
1432 |
> |
((long)(u + UAC_UNIT) << 32)); |
1433 |
> |
if (v.eventCount != (e | INT_SIGN)) |
1434 |
> |
break; |
1435 |
> |
if (U.compareAndSwapLong(this, CTL, c, nc)) { |
1436 |
> |
v.eventCount = (e + E_SEQ) & E_MASK; |
1437 |
> |
if ((p = v.parker) != null) |
1438 |
> |
U.unpark(p); |
1439 |
> |
break; |
1440 |
> |
} |
1441 |
> |
} |
1442 |
> |
else { |
1443 |
> |
if ((short)u < 0) |
1444 |
> |
tryAddWorker(); |
1445 |
> |
break; |
1446 |
> |
} |
1447 |
> |
} |
1448 |
|
} |
1449 |
< |
|
1450 |
< |
if (ex != null) // rethrow |
1449 |
> |
if (ex == null) // help clean refs on way out |
1450 |
> |
ForkJoinTask.helpExpungeStaleExceptions(); |
1451 |
> |
else // rethrow |
1452 |
|
ForkJoinTask.rethrow(ex); |
1453 |
|
} |
1454 |
|
|
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 |
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; |
1653 |
|
* |
1654 |
|
* * If not already enqueued, try to inactivate and enqueue the |
1655 |
|
* worker on wait queue. Or, if inactivating has caused the pool |
1656 |
< |
* to be quiescent, relay to idleAwaitWork to check for |
1657 |
< |
* termination and possibly shrink pool. |
1656 |
> |
* to be quiescent, relay to idleAwaitWork to possibly shrink |
1657 |
> |
* pool. |
1658 |
|
* |
1659 |
|
* * If already enqueued and none of the above apply, possibly |
1660 |
< |
* (with 1/2 probability) park awaiting signal, else lingering to |
1661 |
< |
* help scan and signal. |
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. |
1664 |
|
* |
1665 |
|
* @param w the worker (via its WorkQueue) |
1666 |
|
* @return a task or null if none found |
1671 |
|
if (w != null && (ws = workQueues) != null && (m = ws.length - 1) >= 0) { |
1672 |
|
int ec = w.eventCount; // ec is negative if inactive |
1673 |
|
int r = w.seed; r ^= r << 13; r ^= r >>> 17; w.seed = r ^= r << 5; |
1674 |
+ |
w.hint = -1; // update seed and clear hint |
1675 |
|
int j = ((m + m + 1) | MIN_SCAN) & MAX_SCAN; |
1676 |
|
do { |
1677 |
|
WorkQueue q; ForkJoinTask<?>[] a; int b; |
1693 |
|
} |
1694 |
|
} while (--j >= 0); |
1695 |
|
|
1696 |
< |
long c, sc; int e, ns, h; |
1697 |
< |
if ((h = w.hint) < 0) { |
1698 |
< |
if ((ns = w.nsteals) != 0) { |
1699 |
< |
if (U.compareAndSwapLong(this, STEALCOUNT, |
1700 |
< |
sc = stealCount, sc + ns)) |
1701 |
< |
w.nsteals = 0; // collect steals |
1702 |
< |
} |
1703 |
< |
else if (plock != ps) // consistency check |
1704 |
< |
; // skip |
1705 |
< |
else if ((e = (int)(c = ctl)) < 0) |
1706 |
< |
w.qlock = -1; // pool is terminating |
1707 |
< |
else if (ec >= 0) { // try to enqueue/inactivate |
1708 |
< |
long nc = ((long)ec | ((c - AC_UNIT) & (AC_MASK|TC_MASK))); |
1709 |
< |
w.nextWait = e; // link and mark inactive |
1710 |
< |
w.eventCount = ec | INT_SIGN; |
1711 |
< |
if (ctl != c || !U.compareAndSwapLong(this, CTL, c, nc)) |
1712 |
< |
w.eventCount = ec; // unmark on CAS failure |
1713 |
< |
else if ((int)(c >> AC_SHIFT) == 1 - (config & SMASK)) |
1714 |
< |
idleAwaitWork(w, nc, c); |
1715 |
< |
} |
1716 |
< |
else if (w.eventCount < 0) { // block |
1717 |
< |
Thread wt = Thread.currentThread(); |
1718 |
< |
Thread.interrupted(); // clear status |
1719 |
< |
U.putObject(wt, PARKBLOCKER, this); |
1720 |
< |
w.parker = wt; // emulate LockSupport.park |
1721 |
< |
if (w.eventCount < 0) // recheck |
1722 |
< |
U.park(false, 0L); |
1723 |
< |
w.parker = null; |
1724 |
< |
U.putObject(wt, PARKBLOCKER, null); |
1725 |
< |
} |
1726 |
< |
} |
1727 |
< |
if (h >= 0 || (h = w.hint) >= 0) { // signal others before retry |
1728 |
< |
w.hint = -1; // reset |
1729 |
< |
helpSignal(null, h, true); |
1696 |
> |
int h, e, ns; long c, sc; WorkQueue q; |
1697 |
> |
if ((ns = w.nsteals) != 0) { |
1698 |
> |
if (U.compareAndSwapLong(this, STEALCOUNT, |
1699 |
> |
sc = stealCount, sc + ns)) |
1700 |
> |
w.nsteals = 0; // collect steals and rescan |
1701 |
> |
} |
1702 |
> |
else if (plock != ps) // consistency check |
1703 |
> |
; // skip |
1704 |
> |
else if ((e = (int)(c = ctl)) < 0) |
1705 |
> |
w.qlock = -1; // pool is terminating |
1706 |
> |
else { |
1707 |
> |
if ((h = w.hint) < 0) { |
1708 |
> |
if (ec >= 0) { // try to enqueue/inactivate |
1709 |
> |
long nc = (((long)ec | |
1710 |
> |
((c - AC_UNIT) & (AC_MASK|TC_MASK)))); |
1711 |
> |
w.nextWait = e; // link and mark inactive |
1712 |
> |
w.eventCount = ec | INT_SIGN; |
1713 |
> |
if (ctl != c || !U.compareAndSwapLong(this, CTL, c, nc)) |
1714 |
> |
w.eventCount = ec; // unmark on CAS failure |
1715 |
> |
else if ((int)(c >> AC_SHIFT) == 1 - (config & SMASK)) |
1716 |
> |
idleAwaitWork(w, nc, c); |
1717 |
> |
} |
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); // block |
1725 |
> |
w.parker = null; |
1726 |
> |
U.putObject(wt, PARKBLOCKER, null); |
1727 |
> |
} |
1728 |
> |
} |
1729 |
> |
if ((h >= 0 || (h = w.hint) >= 0) && |
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;;) { |
1734 |
> |
int idleCount = (w.eventCount < 0) ? 0 : -1; |
1735 |
> |
if (((s = idleCount - q.base + q.top) <= n && |
1736 |
> |
(n = s) <= 0) || |
1737 |
> |
(u = (int)((c = ctl) >>> 32)) >= 0 || |
1738 |
> |
(e = (int)c) <= 0 || m < (i = e & SMASK) || |
1739 |
> |
(v = ws[i]) == null) |
1740 |
> |
break; |
1741 |
> |
long nc = (((long)(v.nextWait & E_MASK)) | |
1742 |
> |
((long)(u + UAC_UNIT) << 32)); |
1743 |
> |
if (v.eventCount != (e | INT_SIGN) || |
1744 |
> |
!U.compareAndSwapLong(this, CTL, c, nc)) |
1745 |
> |
break; |
1746 |
> |
v.hint = h; |
1747 |
> |
v.eventCount = (e + E_SEQ) & E_MASK; |
1748 |
> |
if ((p = v.parker) != null) |
1749 |
> |
U.unpark(p); |
1750 |
> |
if (--n <= 0) |
1751 |
> |
break; |
1752 |
> |
} |
1753 |
> |
} |
1754 |
|
} |
1755 |
|
} |
1756 |
|
return null; |
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 - 100000L; // 1ms slop |
1777 |
> |
long deadline = System.nanoTime() + parkTime - TIMEOUT_SLOP; |
1778 |
|
Thread wt = Thread.currentThread(); |
1779 |
|
while (ctl == currentCtl) { |
1780 |
|
Thread.interrupted(); // timed variant of version in scan() |
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 |
|
} |
1798 |
|
} |
1799 |
|
|
1800 |
|
/** |
1801 |
< |
* Scans through queues looking for work (optionally, while |
1802 |
< |
* joining a task); if any present, signals. May return early if |
1803 |
< |
* more signalling is detectably unneeded. |
1801 |
> |
* Scans through queues looking for work while joining a task; if |
1802 |
> |
* any present, signals. May return early if more signalling is |
1803 |
> |
* detectably unneeded. |
1804 |
|
* |
1805 |
< |
* @param task if non-null, return early if done |
1805 |
> |
* @param task return early if done |
1806 |
|
* @param origin an index to start scan |
1785 |
– |
* @param once if only the origin should be checked |
1807 |
|
*/ |
1808 |
< |
private void helpSignal(ForkJoinTask<?> task, int origin, boolean once) { |
1808 |
> |
private void helpSignal(ForkJoinTask<?> task, int origin) { |
1809 |
|
WorkQueue[] ws; WorkQueue w; Thread p; long c; int m, u, e, i, s; |
1810 |
< |
if ((u = (int)(ctl >>> 32)) < 0 && (u >> UAC_SHIFT) < 0 && |
1810 |
> |
if (task != null && task.status >= 0 && |
1811 |
> |
(u = (int)(ctl >>> 32)) < 0 && (u >> UAC_SHIFT) < 0 && |
1812 |
|
(ws = workQueues) != null && (m = ws.length - 1) >= 0) { |
1813 |
< |
outer: for (int k = origin, j = once? 0 : m; j >= 0; --j) { |
1813 |
> |
outer: for (int k = origin, j = m; j >= 0; --j) { |
1814 |
|
WorkQueue q = ws[k++ & m]; |
1815 |
|
for (int n = m;;) { // limit to at most m signals |
1816 |
< |
if (task != null && task.status < 0) |
1816 |
> |
if (task.status < 0) |
1817 |
|
break outer; |
1818 |
|
if (q == null || |
1819 |
< |
((s = (task == null ? -1 : 0) - q.base + q.top) <= n && |
1798 |
< |
(n = s) <= 0)) |
1819 |
> |
((s = -q.base + q.top) <= n && (n = s) <= 0)) |
1820 |
|
break; |
1821 |
|
if ((u = (int)((c = ctl) >>> 32)) >= 0 || |
1822 |
|
(e = (int)c) <= 0 || m < (i = e & SMASK) || |
1824 |
|
break outer; |
1825 |
|
long nc = (((long)(w.nextWait & E_MASK)) | |
1826 |
|
((long)(u + UAC_UNIT) << 32)); |
1827 |
< |
if (w.eventCount == (e | INT_SIGN) && |
1828 |
< |
U.compareAndSwapLong(this, CTL, c, nc)) { |
1827 |
> |
if (w.eventCount != (e | INT_SIGN)) |
1828 |
> |
break outer; |
1829 |
> |
if (U.compareAndSwapLong(this, CTL, c, nc)) { |
1830 |
|
w.eventCount = (e + E_SEQ) & E_MASK; |
1831 |
|
if ((p = w.parker) != null) |
1832 |
|
U.unpark(p); |
1931 |
|
* @param task the task to join |
1932 |
|
* @param mode if shared, exit upon completing any task |
1933 |
|
* if all workers are active |
1912 |
– |
* |
1934 |
|
*/ |
1935 |
|
private int helpComplete(ForkJoinTask<?> task, int mode) { |
1936 |
|
WorkQueue[] ws; WorkQueue q; int m, n, s, u; |
2017 |
|
do {} while ((s = task.status) >= 0 && !joiner.isEmpty() && |
2018 |
|
joiner.tryRemoveAndExec(task)); // process local tasks |
2019 |
|
if (s >= 0 && (s = task.status) >= 0) { |
2020 |
< |
helpSignal(task, joiner.poolIndex, false); |
2020 |
> |
helpSignal(task, joiner.poolIndex); |
2021 |
|
if ((s = task.status) >= 0 && |
2022 |
|
(task instanceof CountedCompleter)) |
2023 |
|
s = helpComplete(task, LIFO_QUEUE); |
2026 |
|
if ((!joiner.isEmpty() || // try helping |
2027 |
|
(s = tryHelpStealer(joiner, task)) == 0) && |
2028 |
|
(s = task.status) >= 0) { |
2029 |
< |
helpSignal(task, joiner.poolIndex, false); |
2029 |
> |
helpSignal(task, joiner.poolIndex); |
2030 |
|
if ((s = task.status) >= 0 && tryCompensate()) { |
2031 |
|
if (task.trySetSignal() && (s = task.status) >= 0) { |
2032 |
|
synchronized (task) { |
2067 |
|
do {} while ((s = task.status) >= 0 && !joiner.isEmpty() && |
2068 |
|
joiner.tryRemoveAndExec(task)); |
2069 |
|
if (s >= 0 && (s = task.status) >= 0) { |
2070 |
< |
helpSignal(task, joiner.poolIndex, false); |
2070 |
> |
helpSignal(task, joiner.poolIndex); |
2071 |
|
if ((s = task.status) >= 0 && |
2072 |
|
(task instanceof CountedCompleter)) |
2073 |
|
s = helpComplete(task, LIFO_QUEUE); |
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, |
2066 |
< |
* 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) { |
2077 |
< |
if (n < -1) |
2078 |
< |
signalWork(q); |
2079 |
< |
return q; |
2080 |
< |
} |
2081 |
< |
else if (--j < 0) { |
2082 |
< |
if (plock == ps) |
2083 |
< |
return null; |
2084 |
< |
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 |
|
|
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 |
2106 |
– |
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; |
2118 |
– |
do {} while (!U.compareAndSwapLong |
2119 |
– |
(this, CTL, c = ctl, c -= AC_UNIT)); |
2120 |
– |
} |
2121 |
– |
else |
2122 |
– |
c = ctl; // re-increment on exit |
2123 |
– |
if ((int)(c >> AC_SHIFT) + (config & SMASK) == 0) { |
2124 |
– |
do {} while (!U.compareAndSwapLong |
2125 |
– |
(this, CTL, c = ctl, c + AC_UNIT)); |
2126 |
– |
break; |
2127 |
– |
} |
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 |
|
|
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 |
|
|
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) |
2241 |
< |
return false; |
2242 |
< |
if (((ps = plock) & PL_LOCK) != 0 || |
2243 |
< |
!U.compareAndSwapInt(this, PLOCK, ps, ps += PL_LOCK)) |
2244 |
< |
ps = acquirePlock(); |
2245 |
< |
int nps = SHUTDOWN; |
2246 |
< |
if (!U.compareAndSwapInt(this, PLOCK, ps, nps)) |
2247 |
< |
releasePlock(nps); |
2248 |
< |
} |
2249 |
< |
if (!now) { // check if idle & no tasks |
2250 |
< |
if ((int)(c >> AC_SHIFT) != -(config & SMASK) || |
2251 |
< |
hasQueuedSubmissions()) |
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 |
< |
// Check for unqueued inactive workers. One pass suffices. |
2268 |
< |
WorkQueue[] ws = workQueues; WorkQueue w; |
2269 |
< |
if (ws != null) { |
2270 |
< |
for (int i = 1; i < ws.length; i += 2) { |
2271 |
< |
if ((w = ws[i]) != null && w.eventCount >= 0) |
2272 |
< |
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) { |
2266 |
< |
WorkQueue w; |
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) { |
2287 |
|
w.qlock = -1; |
2288 |
|
if (pass > 0) { |
2289 |
|
w.cancelAll(); |
2290 |
< |
if (pass > 1) |
2291 |
< |
w.interruptOwner(); |
2290 |
> |
if (pass > 1 && (wt = w.owner) != null) { |
2291 |
> |
if (!wt.isInterrupted()) { |
2292 |
> |
try { |
2293 |
> |
wt.interrupt(); |
2294 |
> |
} catch (Throwable ignore) { |
2295 |
> |
} |
2296 |
> |
} |
2297 |
> |
U.unpark(wt); |
2298 |
> |
} |
2299 |
|
} |
2300 |
|
} |
2301 |
|
} |
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) | |
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; |
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 && |
2402 |
|
(u = (int)(ctl >>> 32)) >= 0 || (u >> UAC_SHIFT) >= 0) |
2403 |
|
break; |
2404 |
|
if (task == null) { |
2405 |
< |
helpSignal(root, q.poolIndex, false); |
2405 |
> |
helpSignal(root, q.poolIndex); |
2406 |
|
if (root.status >= 0) |
2407 |
|
helpComplete(root, SHARED_QUEUE); |
2408 |
|
break; |
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 && |
2445 |
|
if (t instanceof CountedCompleter) |
2446 |
|
p.externalHelpComplete(q, t); |
2447 |
|
else |
2448 |
< |
p.helpSignal(t, q.poolIndex, false); |
2448 |
> |
p.helpSignal(t, q.poolIndex); |
2449 |
|
} |
2450 |
|
} |
2451 |
|
} |
2452 |
|
|
2429 |
– |
/** |
2430 |
– |
* Restricted version of helpQuiescePool for external callers |
2431 |
– |
*/ |
2432 |
– |
static void externalHelpQuiescePool() { |
2433 |
– |
ForkJoinPool p; ForkJoinTask<?> t; WorkQueue q; int b; |
2434 |
– |
if ((p = commonPool) != null && |
2435 |
– |
(q = p.findNonEmptyStealQueue(1)) != null && |
2436 |
– |
(b = q.base) - q.top < 0 && |
2437 |
– |
(t = q.pollAt(b)) != null) |
2438 |
– |
t.doExec(); |
2439 |
– |
} |
2440 |
– |
|
2453 |
|
// Exported methods |
2454 |
|
|
2455 |
|
// Constructors |
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 |
|
|
2548 |
|
} |
2549 |
|
|
2550 |
|
/** |
2551 |
< |
* Returns the common pool instance. |
2551 |
> |
* Returns the common pool instance. This pool is statically |
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 |
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()); |
2669 |
< |
// Workaround needed because method wasn't declared with |
2670 |
< |
// wildcards in return type but should have been. |
2671 |
< |
@SuppressWarnings({"unchecked", "rawtypes"}) |
2672 |
< |
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); |
2679 |
– |
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 |
|
|
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 |
|
/** |
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. |
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 |
3053 |
|
* commenced but not yet completed. This method may be useful for |
3054 |
|
* debugging. A return of {@code true} reported a sufficient |
3055 |
|
* period after shutdown may indicate that submitted tasks have |
3056 |
< |
* ignored or suppressed interruption, or are waiting for IO, |
3056 |
> |
* ignored or suppressed interruption, or are waiting for I/O, |
3057 |
|
* causing this executor not to properly terminate. (See the |
3058 |
|
* advisory notes for class {@link ForkJoinTask} stating that |
3059 |
|
* tasks should not normally entail blocking operations. But if |
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 |
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; |
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 |
|
* |
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; |
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 |
|
} |
3273 |
– |
if ((s & (s-1)) != 0) |
3274 |
– |
throw new Error("data type scale not a power of two"); |
3355 |
|
|
3356 |
|
submitters = new ThreadLocal<Submitter>(); |
3357 |
|
ForkJoinWorkerThreadFactory fac = defaultForkJoinWorkerThreadFactory = |
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 |
|
/** |
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 |
|
} |
3345 |
– |
|
3427 |
|
} |