Java Code Examples for java.util.concurrent.ThreadLocalRandom#getProbe()

The following examples show how to use java.util.concurrent.ThreadLocalRandom#getProbe() . These examples are extracted from open source projects. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example 1
Source Project: hottub   File: ForkJoinPool.java    License: GNU General Public License v2.0 6 votes vote down vote up 
/**
 * Performs tryUnpush for an external submitter: Finds queue,
 * locks if apparently non-empty, validates upon locking, and
 * adjusts top. Each check can fail but rarely does.
 */
final boolean tryExternalUnpush(ForkJoinTask<?> task) {
    WorkQueue[] ws; WorkQueue w; ForkJoinTask<?>[] a; int m, s;
    int r = ThreadLocalRandom.getProbe();
    if ((ws = workQueues) != null && (m = ws.length - 1) >= 0 &&
        (w = ws[m & r & SQMASK]) != null &&
        (a = w.array) != null && (s = w.top) != w.base) {
        long j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE;
        if (U.compareAndSwapInt(w, QLOCK, 0, 1)) {
            if (w.top == s && w.array == a &&
                U.getObject(a, j) == task &&
                U.compareAndSwapObject(a, j, task, null)) {
                U.putOrderedInt(w, QTOP, s - 1);
                U.putOrderedInt(w, QLOCK, 0);
                return true;
            }
            U.compareAndSwapInt(w, QLOCK, 1, 0);
        }
    }
    return false;
}
Example 2
Source Project: jdk1.8-source-analysis   File: ForkJoinPool.java    License: Apache License 2.0 6 votes vote down vote up 
/**
 * Tries to add the given task to a submission queue at
 * submitter's current queue. Only the (vastly) most common path
 * is directly handled in this method, while screening for need
 * for externalSubmit.
 *
 * @param task the task. Caller must ensure non-null.
 */
final void externalPush(ForkJoinTask<?> task) {
    WorkQueue[] ws; WorkQueue q; int m;
    int r = ThreadLocalRandom.getProbe();
    int rs = runState;
    if ((ws = workQueues) != null && (m = (ws.length - 1)) >= 0 &&
        (q = ws[m & r & SQMASK]) != null && r != 0 && rs > 0 &&
        U.compareAndSwapInt(q, QLOCK, 0, 1)) {
        ForkJoinTask<?>[] a; int am, n, s;
        if ((a = q.array) != null &&
            (am = a.length - 1) > (n = (s = q.top) - q.base)) {
            int j = ((am & s) << ASHIFT) + ABASE;
            U.putOrderedObject(a, j, task);
            U.putOrderedInt(q, QTOP, s + 1);
            U.putIntVolatile(q, QLOCK, 0);
            if (n <= 1)
                signalWork(ws, q);
            return;
        }
        U.compareAndSwapInt(q, QLOCK, 1, 0);
    }
    externalSubmit(task);
}
Example 3
Source Project: jdk8u-dev-jdk   File: ForkJoinPool.java    License: GNU General Public License v2.0 6 votes vote down vote up 
/**
 * Performs tryUnpush for an external submitter: Finds queue,
 * locks if apparently non-empty, validates upon locking, and
 * adjusts top. Each check can fail but rarely does.
 */
final boolean tryExternalUnpush(ForkJoinTask<?> task) {
    WorkQueue[] ws; WorkQueue w; ForkJoinTask<?>[] a; int m, s;
    int r = ThreadLocalRandom.getProbe();
    if ((ws = workQueues) != null && (m = ws.length - 1) >= 0 &&
        (w = ws[m & r & SQMASK]) != null &&
        (a = w.array) != null && (s = w.top) != w.base) {
        long j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE;
        if (U.compareAndSwapInt(w, QLOCK, 0, 1)) {
            if (w.top == s && w.array == a &&
                U.getObject(a, j) == task &&
                U.compareAndSwapObject(a, j, task, null)) {
                U.putOrderedInt(w, QTOP, s - 1);
                U.putOrderedInt(w, QLOCK, 0);
                return true;
            }
            U.compareAndSwapInt(w, QLOCK, 1, 0);
        }
    }
    return false;
}
Example 4
Source Project: dragonwell8_jdk   File: ForkJoinPool.java    License: GNU General Public License v2.0 6 votes vote down vote up 
/**
 * Tries to add the given task to a submission queue at
 * submitter's current queue. Only the (vastly) most common path
 * is directly handled in this method, while screening for need
 * for externalSubmit.
 *
 * @param task the task. Caller must ensure non-null.
 */
final void externalPush(ForkJoinTask<?> task) {
    WorkQueue[] ws; WorkQueue q; int m;
    int r = ThreadLocalRandom.getProbe();
    int rs = runState;
    if ((ws = workQueues) != null && (m = (ws.length - 1)) >= 0 &&
        (q = ws[m & r & SQMASK]) != null && r != 0 && rs > 0 &&
        U.compareAndSwapInt(q, QLOCK, 0, 1)) {
        ForkJoinTask<?>[] a; int am, n, s;
        if ((a = q.array) != null &&
            (am = a.length - 1) > (n = (s = q.top) - q.base)) {
            int j = ((am & s) << ASHIFT) + ABASE;
            U.putOrderedObject(a, j, task);
            U.putOrderedInt(q, QTOP, s + 1);
            U.putIntVolatile(q, QLOCK, 0);
            if (n <= 1)
                signalWork(ws, q);
            return;
        }
        U.compareAndSwapInt(q, QLOCK, 1, 0);
    }
    externalSubmit(task);
}
Example 5
Source Project: openjdk-jdk8u-backup   File: ForkJoinPool.java    License: GNU General Public License v2.0 6 votes vote down vote up 
/**
 * Tries to add the given task to a submission queue at
 * submitter's current queue. Only the (vastly) most common path
 * is directly handled in this method, while screening for need
 * for externalSubmit.
 *
 * @param task the task. Caller must ensure non-null.
 */
final void externalPush(ForkJoinTask<?> task) {
    WorkQueue[] ws; WorkQueue q; int m;
    int r = ThreadLocalRandom.getProbe();
    int rs = runState;
    if ((ws = workQueues) != null && (m = (ws.length - 1)) >= 0 &&
        (q = ws[m & r & SQMASK]) != null && r != 0 && rs > 0 &&
        U.compareAndSwapInt(q, QLOCK, 0, 1)) {
        ForkJoinTask<?>[] a; int am, n, s;
        if ((a = q.array) != null &&
            (am = a.length - 1) > (n = (s = q.top) - q.base)) {
            int j = ((am & s) << ASHIFT) + ABASE;
            U.putOrderedObject(a, j, task);
            U.putOrderedInt(q, QTOP, s + 1);
            U.putIntVolatile(q, QLOCK, 0);
            if (n <= 1)
                signalWork(ws, q);
            return;
        }
        U.compareAndSwapInt(q, QLOCK, 1, 0);
    }
    externalSubmit(task);
}
Example 6
Source Project: jdk8u-jdk   File: ForkJoinPool.java    License: GNU General Public License v2.0 6 votes vote down vote up 
/**
 * Tries to add the given task to a submission queue at
 * submitter's current queue. Only the (vastly) most common path
 * is directly handled in this method, while screening for need
 * for externalSubmit.
 *
 * @param task the task. Caller must ensure non-null.
 */
final void externalPush(ForkJoinTask<?> task) {
    WorkQueue[] ws; WorkQueue q; int m;
    int r = ThreadLocalRandom.getProbe();
    int rs = runState;
    if ((ws = workQueues) != null && (m = (ws.length - 1)) >= 0 &&
        (q = ws[m & r & SQMASK]) != null && r != 0 && rs > 0 &&
        U.compareAndSwapInt(q, QLOCK, 0, 1)) {
        ForkJoinTask<?>[] a; int am, n, s;
        if ((a = q.array) != null &&
            (am = a.length - 1) > (n = (s = q.top) - q.base)) {
            int j = ((am & s) << ASHIFT) + ABASE;
            U.putOrderedObject(a, j, task);
            U.putOrderedInt(q, QTOP, s + 1);
            U.putOrderedInt(q, QLOCK, 0);
            if (n <= 1)
                signalWork(ws, q);
            return;
        }
        U.compareAndSwapInt(q, QLOCK, 1, 0);
    }
    externalSubmit(task);
}
Example 7
Source Project: openjdk-jdk8u   File: ForkJoinPool.java    License: GNU General Public License v2.0 6 votes vote down vote up 
/**
 * Tries to add the given task to a submission queue at
 * submitter's current queue. Only the (vastly) most common path
 * is directly handled in this method, while screening for need
 * for externalSubmit.
 *
 * @param task the task. Caller must ensure non-null.
 */
final void externalPush(ForkJoinTask<?> task) {
    WorkQueue[] ws; WorkQueue q; int m;
    int r = ThreadLocalRandom.getProbe();
    int rs = runState;
    if ((ws = workQueues) != null && (m = (ws.length - 1)) >= 0 &&
        (q = ws[m & r & SQMASK]) != null && r != 0 && rs > 0 &&
        U.compareAndSwapInt(q, QLOCK, 0, 1)) {
        ForkJoinTask<?>[] a; int am, n, s;
        if ((a = q.array) != null &&
            (am = a.length - 1) > (n = (s = q.top) - q.base)) {
            int j = ((am & s) << ASHIFT) + ABASE;
            U.putOrderedObject(a, j, task);
            U.putOrderedInt(q, QTOP, s + 1);
            U.putIntVolatile(q, QLOCK, 0);
            if (n <= 1)
                signalWork(ws, q);
            return;
        }
        U.compareAndSwapInt(q, QLOCK, 1, 0);
    }
    externalSubmit(task);
}
Example 8
Source Project: jdk8u_jdk   File: ForkJoinPool.java    License: GNU General Public License v2.0 6 votes vote down vote up 
/**
 * Performs tryUnpush for an external submitter: Finds queue,
 * locks if apparently non-empty, validates upon locking, and
 * adjusts top. Each check can fail but rarely does.
 */
final boolean tryExternalUnpush(ForkJoinTask<?> task) {
    WorkQueue[] ws; WorkQueue w; ForkJoinTask<?>[] a; int m, s;
    int r = ThreadLocalRandom.getProbe();
    if ((ws = workQueues) != null && (m = ws.length - 1) >= 0 &&
        (w = ws[m & r & SQMASK]) != null &&
        (a = w.array) != null && (s = w.top) != w.base) {
        long j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE;
        if (U.compareAndSwapInt(w, QLOCK, 0, 1)) {
            if (w.top == s && w.array == a &&
                U.getObject(a, j) == task &&
                U.compareAndSwapObject(a, j, task, null)) {
                U.putOrderedInt(w, QTOP, s - 1);
                U.putOrderedInt(w, QLOCK, 0);
                return true;
            }
            U.compareAndSwapInt(w, QLOCK, 1, 0);
        }
    }
    return false;
}
Example 9
Source Project: jdk8u-jdk   File: ForkJoinPool.java    License: GNU General Public License v2.0 6 votes vote down vote up 
/**
 * Performs tryUnpush for an external submitter: Finds queue,
 * locks if apparently non-empty, validates upon locking, and
 * adjusts top. Each check can fail but rarely does.
 */
final boolean tryExternalUnpush(ForkJoinTask<?> task) {
    WorkQueue[] ws; WorkQueue w; ForkJoinTask<?>[] a; int m, s;
    int r = ThreadLocalRandom.getProbe();
    if ((ws = workQueues) != null && (m = ws.length - 1) >= 0 &&
        (w = ws[m & r & SQMASK]) != null &&
        (a = w.array) != null && (s = w.top) != w.base) {
        long j = (((a.length - 1) & (s - 1)) << ASHIFT) + ABASE;
        if (U.compareAndSwapInt(w, QLOCK, 0, 1)) {
            if (w.top == s && w.array == a &&
                U.getObject(a, j) == task &&
                U.compareAndSwapObject(a, j, task, null)) {
                U.putOrderedInt(w, QTOP, s - 1);
                U.putOrderedInt(w, QLOCK, 0);
                return true;
            }
            U.compareAndSwapInt(w, QLOCK, 1, 0);
        }
    }
    return false;
}
Example 10
Source Project: jdk8u-dev-jdk   File: ForkJoinPool.java    License: GNU General Public License v2.0 5 votes vote down vote up 
/**
 * Performs helpComplete for an external submitter.
 */
final int externalHelpComplete(CountedCompleter<?> task, int maxTasks) {
    WorkQueue[] ws; int n;
    int r = ThreadLocalRandom.getProbe();
    return ((ws = workQueues) == null || (n = ws.length) == 0) ? 0 :
        helpComplete(ws[(n - 1) & r & SQMASK], task, maxTasks);
}
Example 11
Source Project: jdk8u_jdk   File: ForkJoinPool.java    License: GNU General Public License v2.0 5 votes vote down vote up 
/**
 * Performs helpComplete for an external submitter.
 */
final int externalHelpComplete(CountedCompleter<?> task, int maxTasks) {
    WorkQueue[] ws; int n;
    int r = ThreadLocalRandom.getProbe();
    return ((ws = workQueues) == null || (n = ws.length) == 0) ? 0 :
        helpComplete(ws[(n - 1) & r & SQMASK], task, maxTasks);
}
Example 12
Source Project: JDKSourceCode1.8   File: ForkJoinPool.java    License: MIT License 5 votes vote down vote up 
/**
 * Performs helpComplete for an external submitter.
 */
final int externalHelpComplete(CountedCompleter<?> task, int maxTasks) {
    WorkQueue[] ws; int n;
    int r = ThreadLocalRandom.getProbe();
    return ((ws = workQueues) == null || (n = ws.length) == 0) ? 0 :
        helpComplete(ws[(n - 1) & r & SQMASK], task, maxTasks);
}
Example 13
Source Project: hottub   File: ForkJoinPool.java    License: GNU General Public License v2.0 5 votes vote down vote up 
/**
 * Performs helpComplete for an external submitter.
 */
final int externalHelpComplete(CountedCompleter<?> task, int maxTasks) {
    WorkQueue[] ws; int n;
    int r = ThreadLocalRandom.getProbe();
    return ((ws = workQueues) == null || (n = ws.length) == 0) ? 0 :
        helpComplete(ws[(n - 1) & r & SQMASK], task, maxTasks);
}
Example 14
Source Project: TencentKona-8   File: ForkJoinPool.java    License: GNU General Public License v2.0 5 votes vote down vote up 
/**
 * Performs helpComplete for an external submitter.
 */
final int externalHelpComplete(CountedCompleter<?> task, int maxTasks) {
    WorkQueue[] ws; int n;
    int r = ThreadLocalRandom.getProbe();
    return ((ws = workQueues) == null || (n = ws.length) == 0) ? 0 :
        helpComplete(ws[(n - 1) & r & SQMASK], task, maxTasks);
}
Example 15
Source Project: jdk8u-jdk   File: ForkJoinPool.java    License: GNU General Public License v2.0 5 votes vote down vote up 
/**
 * Returns common pool queue for an external thread.
 */
static WorkQueue commonSubmitterQueue() {
    ForkJoinPool p = common;
    int r = ThreadLocalRandom.getProbe();
    WorkQueue[] ws; int m;
    return (p != null && (ws = p.workQueues) != null &&
            (m = ws.length - 1) >= 0) ?
        ws[m & r & SQMASK] : null;
}
Example 16
Source Project: jdk8u-jdk   File: ForkJoinPool.java    License: GNU General Public License v2.0 5 votes vote down vote up 
/**
 * Performs helpComplete for an external submitter.
 */
final int externalHelpComplete(CountedCompleter<?> task, int maxTasks) {
    WorkQueue[] ws; int n;
    int r = ThreadLocalRandom.getProbe();
    return ((ws = workQueues) == null || (n = ws.length) == 0) ? 0 :
        helpComplete(ws[(n - 1) & r & SQMASK], task, maxTasks);
}
Example 17
Source Project: jdk8u60   File: ForkJoinPool.java    License: GNU General Public License v2.0 5 votes vote down vote up 
/**
 * Performs helpComplete for an external submitter.
 */
final int externalHelpComplete(CountedCompleter<?> task, int maxTasks) {
    WorkQueue[] ws; int n;
    int r = ThreadLocalRandom.getProbe();
    return ((ws = workQueues) == null || (n = ws.length) == 0) ? 0 :
        helpComplete(ws[(n - 1) & r & SQMASK], task, maxTasks);
}
Example 18
Source Project: jdk8u-jdk   File: ForkJoinPool.java    License: GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Full version of externalPush, handling uncommon cases, as well
 * as performing secondary initialization upon the first
 * submission of the first task to the pool.  It also detects
 * first submission by an external thread and creates a new shared
 * queue if the one at index if empty or contended.
 *
 * @param task the task. Caller must ensure non-null.
 */
private void externalSubmit(ForkJoinTask<?> task) {
    int r;                                    // initialize caller's probe
    if ((r = ThreadLocalRandom.getProbe()) == 0) {
        ThreadLocalRandom.localInit();
        r = ThreadLocalRandom.getProbe();
    }
    for (;;) {
        WorkQueue[] ws; WorkQueue q; int rs, m, k;
        boolean move = false;
        if ((rs = runState) < 0) {
            tryTerminate(false, false);     // help terminate
            throw new RejectedExecutionException();
        }
        else if ((rs & STARTED) == 0 ||     // initialize
                 ((ws = workQueues) == null || (m = ws.length - 1) < 0)) {
            int ns = 0;
            rs = lockRunState();
            try {
                if ((rs & STARTED) == 0) {
                    U.compareAndSwapObject(this, STEALCOUNTER, null,
                                           new AtomicLong());
                    // create workQueues array with size a power of two
                    int p = config & SMASK; // ensure at least 2 slots
                    int n = (p > 1) ? p - 1 : 1;
                    n |= n >>> 1; n |= n >>> 2;  n |= n >>> 4;
                    n |= n >>> 8; n |= n >>> 16; n = (n + 1) << 1;
                    workQueues = new WorkQueue[n];
                    ns = STARTED;
                }
            } finally {
                unlockRunState(rs, (rs & ~RSLOCK) | ns);
            }
        }
        else if ((q = ws[k = r & m & SQMASK]) != null) {
            if (q.qlock == 0 && U.compareAndSwapInt(q, QLOCK, 0, 1)) {
                ForkJoinTask<?>[] a = q.array;
                int s = q.top;
                boolean submitted = false; // initial submission or resizing
                try {                      // locked version of push
                    if ((a != null && a.length > s + 1 - q.base) ||
                        (a = q.growArray()) != null) {
                        int j = (((a.length - 1) & s) << ASHIFT) + ABASE;
                        U.putOrderedObject(a, j, task);
                        U.putOrderedInt(q, QTOP, s + 1);
                        submitted = true;
                    }
                } finally {
                    U.compareAndSwapInt(q, QLOCK, 1, 0);
                }
                if (submitted) {
                    signalWork(ws, q);
                    return;
                }
            }
            move = true;                   // move on failure
        }
        else if (((rs = runState) & RSLOCK) == 0) { // create new queue
            q = new WorkQueue(this, null);
            q.hint = r;
            q.config = k | SHARED_QUEUE;
            q.scanState = INACTIVE;
            rs = lockRunState();           // publish index
            if (rs > 0 &&  (ws = workQueues) != null &&
                k < ws.length && ws[k] == null)
                ws[k] = q;                 // else terminated
            unlockRunState(rs, rs & ~RSLOCK);
        }
        else
            move = true;                   // move if busy
        if (move)
            r = ThreadLocalRandom.advanceProbe(r);
    }
}
Example 19
Source Project: openjdk-jdk8u-backup   File: ForkJoinPool.java    License: GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Full version of externalPush, handling uncommon cases, as well
 * as performing secondary initialization upon the first
 * submission of the first task to the pool.  It also detects
 * first submission by an external thread and creates a new shared
 * queue if the one at index if empty or contended.
 *
 * @param task the task. Caller must ensure non-null.
 */
private void externalSubmit(ForkJoinTask<?> task) {
    int r;                                    // initialize caller's probe
    if ((r = ThreadLocalRandom.getProbe()) == 0) {
        ThreadLocalRandom.localInit();
        r = ThreadLocalRandom.getProbe();
    }
    for (;;) {
        WorkQueue[] ws; WorkQueue q; int rs, m, k;
        boolean move = false;
        if ((rs = runState) < 0) {
            tryTerminate(false, false);     // help terminate
            throw new RejectedExecutionException();
        }
        else if ((rs & STARTED) == 0 ||     // initialize
                 ((ws = workQueues) == null || (m = ws.length - 1) < 0)) {
            int ns = 0;
            rs = lockRunState();
            try {
                if ((rs & STARTED) == 0) {
                    U.compareAndSwapObject(this, STEALCOUNTER, null,
                                           new AtomicLong());
                    // create workQueues array with size a power of two
                    int p = config & SMASK; // ensure at least 2 slots
                    int n = (p > 1) ? p - 1 : 1;
                    n |= n >>> 1; n |= n >>> 2;  n |= n >>> 4;
                    n |= n >>> 8; n |= n >>> 16; n = (n + 1) << 1;
                    workQueues = new WorkQueue[n];
                    ns = STARTED;
                }
            } finally {
                unlockRunState(rs, (rs & ~RSLOCK) | ns);
            }
        }
        else if ((q = ws[k = r & m & SQMASK]) != null) {
            if (q.qlock == 0 && U.compareAndSwapInt(q, QLOCK, 0, 1)) {
                ForkJoinTask<?>[] a = q.array;
                int s = q.top;
                boolean submitted = false; // initial submission or resizing
                try {                      // locked version of push
                    if ((a != null && a.length > s + 1 - q.base) ||
                        (a = q.growArray()) != null) {
                        int j = (((a.length - 1) & s) << ASHIFT) + ABASE;
                        U.putOrderedObject(a, j, task);
                        U.putOrderedInt(q, QTOP, s + 1);
                        submitted = true;
                    }
                } finally {
                    U.compareAndSwapInt(q, QLOCK, 1, 0);
                }
                if (submitted) {
                    signalWork(ws, q);
                    return;
                }
            }
            move = true;                   // move on failure
        }
        else if (((rs = runState) & RSLOCK) == 0) { // create new queue
            q = new WorkQueue(this, null);
            q.hint = r;
            q.config = k | SHARED_QUEUE;
            q.scanState = INACTIVE;
            rs = lockRunState();           // publish index
            if (rs > 0 &&  (ws = workQueues) != null &&
                k < ws.length && ws[k] == null)
                ws[k] = q;                 // else terminated
            unlockRunState(rs, rs & ~RSLOCK);
        }
        else
            move = true;                   // move if busy
        if (move)
            r = ThreadLocalRandom.advanceProbe(r);
    }
}
Example 20
Source Project: Java8CN   File: ForkJoinPool.java    License: Apache License 2.0 4 votes vote down vote up 
/**
 * Full version of externalPush, handling uncommon cases, as well
 * as performing secondary initialization upon the first
 * submission of the first task to the pool.  It also detects
 * first submission by an external thread and creates a new shared
 * queue if the one at index if empty or contended.
 *
 * @param task the task. Caller must ensure non-null.
 */
private void externalSubmit(ForkJoinTask<?> task) {
    int r;                                    // initialize caller's probe
    if ((r = ThreadLocalRandom.getProbe()) == 0) {
        ThreadLocalRandom.localInit();
        r = ThreadLocalRandom.getProbe();
    }
    for (;;) {
        WorkQueue[] ws; WorkQueue q; int rs, m, k;
        boolean move = false;
        if ((rs = runState) < 0) {
            tryTerminate(false, false);     // help terminate
            throw new RejectedExecutionException();
        }
        else if ((rs & STARTED) == 0 ||     // initialize
                 ((ws = workQueues) == null || (m = ws.length - 1) < 0)) {
            int ns = 0;
            rs = lockRunState();
            try {
                if ((rs & STARTED) == 0) {
                    U.compareAndSwapObject(this, STEALCOUNTER, null,
                                           new AtomicLong());
                    // create workQueues array with size a power of two
                    int p = config & SMASK; // ensure at least 2 slots
                    int n = (p > 1) ? p - 1 : 1;
                    n |= n >>> 1; n |= n >>> 2;  n |= n >>> 4;
                    n |= n >>> 8; n |= n >>> 16; n = (n + 1) << 1;
                    workQueues = new WorkQueue[n];
                    ns = STARTED;
                }
            } finally {
                unlockRunState(rs, (rs & ~RSLOCK) | ns);
            }
        }
        else if ((q = ws[k = r & m & SQMASK]) != null) {
            if (q.qlock == 0 && U.compareAndSwapInt(q, QLOCK, 0, 1)) {
                ForkJoinTask<?>[] a = q.array;
                int s = q.top;
                boolean submitted = false; // initial submission or resizing
                try {                      // locked version of push
                    if ((a != null && a.length > s + 1 - q.base) ||
                        (a = q.growArray()) != null) {
                        int j = (((a.length - 1) & s) << ASHIFT) + ABASE;
                        U.putOrderedObject(a, j, task);
                        U.putOrderedInt(q, QTOP, s + 1);
                        submitted = true;
                    }
                } finally {
                    U.compareAndSwapInt(q, QLOCK, 1, 0);
                }
                if (submitted) {
                    signalWork(ws, q);
                    return;
                }
            }
            move = true;                   // move on failure
        }
        else if (((rs = runState) & RSLOCK) == 0) { // create new queue
            q = new WorkQueue(this, null);
            q.hint = r;
            q.config = k | SHARED_QUEUE;
            q.scanState = INACTIVE;
            rs = lockRunState();           // publish index
            if (rs > 0 &&  (ws = workQueues) != null &&
                k < ws.length && ws[k] == null)
                ws[k] = q;                 // else terminated
            unlockRunState(rs, rs & ~RSLOCK);
        }
        else
            move = true;                   // move if busy
        if (move)
            r = ThreadLocalRandom.advanceProbe(r);
    }
}