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8215326: Test java/util/concurrent/ConcurrentHashMap/ToArray.java hangs after j.u.c updates
Reviewed-by: martin, dholmes
This commit is contained in:
Doug Lea
parent
cf21c5ef11
commit
3d9ab36ca0
1 changed files with 52 additions and 61 deletions
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@ -445,7 +445,8 @@ public class ForkJoinPool extends AbstractExecutorService {
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* if to its current value). This would be extremely costly. So
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* we relax it in several ways: (1) Producers only signal when
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* their queue is possibly empty at some point during a push
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* operation. (2) Other workers propagate this signal
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* operation (which requires conservatively checking size zero or
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* one to cover races). (2) Other workers propagate this signal
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* when they find tasks in a queue with size greater than one. (3)
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* Workers only enqueue after scanning (see below) and not finding
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* any tasks. (4) Rather than CASing ctl to its current value in
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@ -761,8 +762,10 @@ public class ForkJoinPool extends AbstractExecutorService {
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/**
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* The maximum number of top-level polls per worker before
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* checking other queues, expressed as a bit shift. See above for
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* rationale.
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* checking other queues, expressed as a bit shift to, in effect,
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* multiply by pool size, and then use as random value mask, so
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* average bound is about poolSize*(1<<TOP_BOUND_SHIFT). See
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* above for rationale.
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*/
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static final int TOP_BOUND_SHIFT = 10;
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@ -838,17 +841,18 @@ public class ForkJoinPool extends AbstractExecutorService {
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*/
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final void push(ForkJoinTask<?> task) {
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ForkJoinTask<?>[] a;
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int s = top, d = s - base, cap, m;
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int s = top, d, cap, m;
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ForkJoinPool p = pool;
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if ((a = array) != null && (cap = a.length) > 0) {
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QA.setRelease(a, (m = cap - 1) & s, task);
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top = s + 1;
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if (d == m)
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growArray(false);
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else if (QA.getAcquire(a, m & (s - 1)) == null && p != null) {
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VarHandle.fullFence(); // was empty
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p.signalWork(null);
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if (((d = s - (int)BASE.getAcquire(this)) & ~1) == 0 &&
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p != null) { // size 0 or 1
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VarHandle.fullFence();
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p.signalWork();
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}
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else if (d == m)
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growArray(false);
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}
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}
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@ -859,16 +863,16 @@ public class ForkJoinPool extends AbstractExecutorService {
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final boolean lockedPush(ForkJoinTask<?> task) {
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ForkJoinTask<?>[] a;
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boolean signal = false;
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int s = top, d = s - base, cap, m;
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int s = top, b = base, cap, d;
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if ((a = array) != null && (cap = a.length) > 0) {
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a[(m = (cap - 1)) & s] = task;
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a[(cap - 1) & s] = task;
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top = s + 1;
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if (d == m)
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if (b - s + cap - 1 == 0)
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growArray(true);
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else {
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phase = 0; // full volatile unlock
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if (a[m & (s - 1)] == null)
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signal = true; // was empty
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if (((s - base) & ~1) == 0) // size 0 or 1
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signal = true;
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}
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}
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return signal;
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@ -1010,23 +1014,17 @@ public class ForkJoinPool extends AbstractExecutorService {
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* queue, up to bound n (to avoid infinite unfairness).
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*/
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final void topLevelExec(ForkJoinTask<?> t, WorkQueue q, int n) {
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if (t != null && q != null) { // hoist checks
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int nstolen = 1;
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for (int j = 0;;) {
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if (t != null)
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for (;;) {
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t.doExec();
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if (j++ <= n)
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t = nextLocalTask();
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else {
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j = 0;
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t = null;
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}
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if (t == null) {
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if (q != null && (t = q.poll()) != null) {
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++nstolen;
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j = 0;
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}
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else if (j != 0)
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if (n-- < 0)
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break;
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else if ((t = nextLocalTask()) == null) {
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if ((t = q.poll()) == null)
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break;
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else
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++nstolen;
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}
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}
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ForkJoinWorkerThread thread = owner;
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@ -1035,6 +1033,7 @@ public class ForkJoinPool extends AbstractExecutorService {
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if (thread != null)
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thread.afterTopLevelExec();
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}
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}
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/**
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* If present, removes task from queue and executes it.
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@ -1456,7 +1455,7 @@ public class ForkJoinPool extends AbstractExecutorService {
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if (!tryTerminate(false, false) && // possibly replace worker
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w != null && w.array != null) // avoid repeated failures
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signalWork(null);
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signalWork();
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if (ex == null) // help clean on way out
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ForkJoinTask.helpExpungeStaleExceptions();
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@ -1466,9 +1465,8 @@ public class ForkJoinPool extends AbstractExecutorService {
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/**
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* Tries to create or release a worker if too few are running.
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* @param q if non-null recheck if empty on CAS failure
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*/
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final void signalWork(WorkQueue q) {
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final void signalWork() {
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for (;;) {
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long c; int sp; WorkQueue[] ws; int i; WorkQueue v;
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if ((c = ctl) >= 0L) // enough workers
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@ -1495,8 +1493,6 @@ public class ForkJoinPool extends AbstractExecutorService {
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LockSupport.unpark(vt);
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break;
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}
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else if (q != null && q.isEmpty()) // no need to retry
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break;
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}
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}
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}
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@ -1617,8 +1613,7 @@ public class ForkJoinPool extends AbstractExecutorService {
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else if (rc <= 0 && (md & SHUTDOWN) != 0 &&
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tryTerminate(false, false))
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break; // quiescent shutdown
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else if (w.phase < 0) {
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if (rc <= 0 && pred != 0 && phase == (int)c) {
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else if (rc <= 0 && pred != 0 && phase == (int)c) {
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long nc = (UC_MASK & (c - TC_UNIT)) | (SP_MASK & pred);
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long d = keepAlive + System.currentTimeMillis();
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LockSupport.parkUntil(this, d);
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@ -1629,12 +1624,8 @@ public class ForkJoinPool extends AbstractExecutorService {
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break;
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}
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}
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else {
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LockSupport.park(this);
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if (w.phase < 0) // one spurious wakeup check
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LockSupport.park(this);
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}
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}
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else if (w.phase < 0)
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LockSupport.park(this); // OK if spuriously woken
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w.source = 0; // disable signal
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}
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}
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@ -1650,8 +1641,8 @@ public class ForkJoinPool extends AbstractExecutorService {
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WorkQueue[] ws; int n;
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if ((ws = workQueues) != null && (n = ws.length) > 0 && w != null) {
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for (int m = n - 1, j = r & m;;) {
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WorkQueue q; int b, s;
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if ((q = ws[j]) != null && (s = q.top) != (b = q.base)) {
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WorkQueue q; int b;
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if ((q = ws[j]) != null && q.top != (b = q.base)) {
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int qid = q.id;
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ForkJoinTask<?>[] a; int cap, k; ForkJoinTask<?> t;
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if ((a = q.array) != null && (cap = a.length) > 0) {
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@ -1660,10 +1651,10 @@ public class ForkJoinPool extends AbstractExecutorService {
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QA.compareAndSet(a, k, t, null)) {
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q.base = b;
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w.source = qid;
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if (s != b && a[(cap - 1) & b] != null)
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signalWork(q); // help signal if more tasks
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if (q.top - b > 0)
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signalWork();
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w.topLevelExec(t, q, // random fairness bound
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(r | (1 << TOP_BOUND_SHIFT)) & SMASK);
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r & ((n << TOP_BOUND_SHIFT) - 1));
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}
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}
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return true;
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@ -1909,7 +1900,7 @@ public class ForkJoinPool extends AbstractExecutorService {
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r = ThreadLocalRandom.advanceProbe(r);
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else {
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if (q.lockedPush(task))
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signalWork(null);
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signalWork();
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return;
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}
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}
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