5 |
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*/ |
6 |
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|
7 |
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package jsr166y; |
8 |
< |
import java.util.*; |
8 |
> |
|
9 |
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import java.util.concurrent.*; |
10 |
< |
import java.util.concurrent.locks.*; |
11 |
< |
import java.util.concurrent.atomic.*; |
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import sun.misc.Unsafe; |
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< |
import java.lang.reflect.*; |
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> |
|
11 |
> |
import java.util.ArrayList; |
12 |
> |
import java.util.Arrays; |
13 |
> |
import java.util.Collection; |
14 |
> |
import java.util.Collections; |
15 |
> |
import java.util.List; |
16 |
> |
import java.util.concurrent.locks.Condition; |
17 |
> |
import java.util.concurrent.locks.LockSupport; |
18 |
> |
import java.util.concurrent.locks.ReentrantLock; |
19 |
> |
import java.util.concurrent.atomic.AtomicInteger; |
20 |
> |
import java.util.concurrent.atomic.AtomicLong; |
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|
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/** |
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* An {@link ExecutorService} for running {@link ForkJoinTask}s. A |
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* most tasks spawn other subtasks (as do most ForkJoinTasks), as well |
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* as the mixed execution of some plain Runnable- or Callable- based |
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* activities along with ForkJoinTasks. When setting |
38 |
< |
* <tt>setAsyncMode</tt>, a ForkJoinPools may also be appropriate for |
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> |
* {@code setAsyncMode}, a ForkJoinPools may also be appropriate for |
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* use with fine-grained tasks that are never joined. Otherwise, other |
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* ExecutorService implementations are typically more appropriate |
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* choices. |
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* adding, suspending, or resuming threads, even if some tasks are |
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* waiting to join others. However, no such adjustments are performed |
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* in the face of blocked IO or other unmanaged synchronization. The |
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* nested <code>ManagedBlocker</code> interface enables extension of |
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> |
* nested {@code ManagedBlocker} interface enables extension of |
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* the kinds of synchronization accommodated. The target parallelism |
50 |
< |
* level may also be changed dynamically (<code>setParallelism</code>) |
50 |
> |
* level may also be changed dynamically ({@code setParallelism}) |
51 |
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* and thread construction can be limited using methods |
52 |
< |
* <code>setMaximumPoolSize</code> and/or |
53 |
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* <code>setMaintainsParallelism</code>. |
52 |
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* {@code setMaximumPoolSize} and/or |
53 |
> |
* {@code setMaintainsParallelism}. |
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* |
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* <p>In addition to execution and lifecycle control methods, this |
56 |
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* class provides status check methods (for example |
57 |
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* <code>getStealCount</code>) that are intended to aid in developing, |
57 |
> |
* {@code getStealCount}) that are intended to aid in developing, |
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* tuning, and monitoring fork/join applications. Also, method |
59 |
< |
* <code>toString</code> returns indications of pool state in a |
59 |
> |
* {@code toString} returns indications of pool state in a |
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* convenient form for informal monitoring. |
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* |
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* <p><b>Implementation notes</b>: This implementation restricts the |
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* maximum number of running threads to 32767. Attempts to create |
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* pools with greater than the maximum result in |
65 |
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* IllegalArgumentExceptions. |
66 |
+ |
* |
67 |
+ |
* @since 1.7 |
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+ |
* @author Doug Lea |
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*/ |
70 |
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public class ForkJoinPool extends AbstractExecutorService { |
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|
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* Returns a new worker thread operating in the given pool. |
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* |
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* @param pool the pool this thread works in |
94 |
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* @throws NullPointerException if pool is null; |
94 |
> |
* @throws NullPointerException if pool is null |
95 |
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*/ |
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public ForkJoinWorkerThread newThread(ForkJoinPool pool); |
97 |
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} |
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|
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/** |
100 |
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* Default ForkJoinWorkerThreadFactory implementation, creates a |
100 |
> |
* Default ForkJoinWorkerThreadFactory implementation; creates a |
101 |
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* new ForkJoinWorkerThread. |
102 |
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*/ |
103 |
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static class DefaultForkJoinWorkerThreadFactory |
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|
164 |
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/** |
165 |
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* The uncaught exception handler used when any worker |
166 |
< |
* abrupty terminates |
166 |
> |
* abruptly terminates |
167 |
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*/ |
168 |
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private Thread.UncaughtExceptionHandler ueh; |
169 |
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|
191 |
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private final LinkedTransferQueue<ForkJoinTask<?>> submissionQueue; |
192 |
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|
193 |
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/** |
194 |
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* Head of Treiber stack for barrier sync. See below for explanation |
194 |
> |
* Head of Treiber stack for barrier sync. See below for explanation. |
195 |
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*/ |
196 |
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private volatile WaitQueueNode syncStack; |
197 |
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|
227 |
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* making decisions about creating and suspending spare |
228 |
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* threads. Updated only by CAS. Note: CASes in |
229 |
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* updateRunningCount and preJoin assume that running active count |
230 |
< |
* is in low word, so need to be modified if this changes |
230 |
> |
* is in low word, so need to be modified if this changes. |
231 |
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*/ |
232 |
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private volatile int workerCounts; |
233 |
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|
236 |
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private static int workerCountsFor(int t, int r) { return (t << 16) + r; } |
237 |
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|
238 |
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/** |
239 |
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* Add delta (which may be negative) to running count. This must |
239 |
> |
* Adds delta (which may be negative) to running count. This must |
240 |
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* be called before (with negative arg) and after (with positive) |
241 |
< |
* any managed synchronization (i.e., mainly, joins) |
241 |
> |
* any managed synchronization (i.e., mainly, joins). |
242 |
> |
* |
243 |
|
* @param delta the number to add |
244 |
|
*/ |
245 |
|
final void updateRunningCount(int delta) { |
246 |
|
int s; |
247 |
< |
do;while (!casWorkerCounts(s = workerCounts, s + delta)); |
247 |
> |
do {} while (!casWorkerCounts(s = workerCounts, s + delta)); |
248 |
|
} |
249 |
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|
250 |
|
/** |
251 |
< |
* Add delta (which may be negative) to both total and running |
251 |
> |
* Adds delta (which may be negative) to both total and running |
252 |
|
* count. This must be called upon creation and termination of |
253 |
|
* worker threads. |
254 |
+ |
* |
255 |
|
* @param delta the number to add |
256 |
|
*/ |
257 |
|
private void updateWorkerCount(int delta) { |
258 |
|
int d = delta + (delta << 16); // add to both lo and hi parts |
259 |
|
int s; |
260 |
< |
do;while (!casWorkerCounts(s = workerCounts, s + d)); |
260 |
> |
do {} while (!casWorkerCounts(s = workerCounts, s + d)); |
261 |
|
} |
262 |
|
|
263 |
|
/** |
283 |
|
private static int runControlFor(int r, int a) { return (r << 16) + a; } |
284 |
|
|
285 |
|
/** |
286 |
< |
* Try incrementing active count; fail on contention. Called by |
287 |
< |
* workers before/during executing tasks. |
288 |
< |
* @return true on success; |
286 |
> |
* Tries incrementing active count; fails on contention. |
287 |
> |
* Called by workers before/during executing tasks. |
288 |
> |
* |
289 |
> |
* @return true on success |
290 |
|
*/ |
291 |
|
final boolean tryIncrementActiveCount() { |
292 |
|
int c = runControl; |
294 |
|
} |
295 |
|
|
296 |
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/** |
297 |
< |
* Try decrementing active count; fail on contention. |
298 |
< |
* Possibly trigger termination on success |
297 |
> |
* Tries decrementing active count; fails on contention. |
298 |
> |
* Possibly triggers termination on success. |
299 |
|
* Called by workers when they can't find tasks. |
300 |
+ |
* |
301 |
|
* @return true on success |
302 |
|
*/ |
303 |
|
final boolean tryDecrementActiveCount() { |
311 |
|
} |
312 |
|
|
313 |
|
/** |
314 |
< |
* Return true if argument represents zero active count and |
314 |
> |
* Returns true if argument represents zero active count and |
315 |
|
* nonzero runstate, which is the triggering condition for |
316 |
|
* terminating on shutdown. |
317 |
|
*/ |
318 |
|
private static boolean canTerminateOnShutdown(int c) { |
319 |
< |
return ((c & -c) >>> 16) != 0; // i.e. least bit is nonzero runState bit |
319 |
> |
// i.e. least bit is nonzero runState bit |
320 |
> |
return ((c & -c) >>> 16) != 0; |
321 |
|
} |
322 |
|
|
323 |
|
/** |
343 |
|
|
344 |
|
/** |
345 |
|
* Creates a ForkJoinPool with a pool size equal to the number of |
346 |
< |
* processors available on the system and using the default |
347 |
< |
* ForkJoinWorkerThreadFactory, |
346 |
> |
* processors available on the system, using the default |
347 |
> |
* ForkJoinWorkerThreadFactory. |
348 |
> |
* |
349 |
|
* @throws SecurityException if a security manager exists and |
350 |
|
* the caller is not permitted to modify threads |
351 |
|
* because it does not hold {@link |
352 |
< |
* java.lang.RuntimePermission}<code>("modifyThread")</code>, |
352 |
> |
* java.lang.RuntimePermission}{@code ("modifyThread")} |
353 |
|
*/ |
354 |
|
public ForkJoinPool() { |
355 |
|
this(Runtime.getRuntime().availableProcessors(), |
357 |
|
} |
358 |
|
|
359 |
|
/** |
360 |
< |
* Creates a ForkJoinPool with the indicated parellelism level |
361 |
< |
* threads, and using the default ForkJoinWorkerThreadFactory, |
360 |
> |
* Creates a ForkJoinPool with the indicated parallelism level |
361 |
> |
* threads and using the default ForkJoinWorkerThreadFactory. |
362 |
> |
* |
363 |
|
* @param parallelism the number of worker threads |
364 |
|
* @throws IllegalArgumentException if parallelism less than or |
365 |
|
* equal to zero |
366 |
|
* @throws SecurityException if a security manager exists and |
367 |
|
* the caller is not permitted to modify threads |
368 |
|
* because it does not hold {@link |
369 |
< |
* java.lang.RuntimePermission}<code>("modifyThread")</code>, |
369 |
> |
* java.lang.RuntimePermission}{@code ("modifyThread")} |
370 |
|
*/ |
371 |
|
public ForkJoinPool(int parallelism) { |
372 |
|
this(parallelism, defaultForkJoinWorkerThreadFactory); |
375 |
|
/** |
376 |
|
* Creates a ForkJoinPool with parallelism equal to the number of |
377 |
|
* processors available on the system and using the given |
378 |
< |
* ForkJoinWorkerThreadFactory, |
378 |
> |
* ForkJoinWorkerThreadFactory. |
379 |
> |
* |
380 |
|
* @param factory the factory for creating new threads |
381 |
|
* @throws NullPointerException if factory is null |
382 |
|
* @throws SecurityException if a security manager exists and |
383 |
|
* the caller is not permitted to modify threads |
384 |
|
* because it does not hold {@link |
385 |
< |
* java.lang.RuntimePermission}<code>("modifyThread")</code>, |
385 |
> |
* java.lang.RuntimePermission}{@code ("modifyThread")} |
386 |
|
*/ |
387 |
|
public ForkJoinPool(ForkJoinWorkerThreadFactory factory) { |
388 |
|
this(Runtime.getRuntime().availableProcessors(), factory); |
394 |
|
* @param parallelism the targeted number of worker threads |
395 |
|
* @param factory the factory for creating new threads |
396 |
|
* @throws IllegalArgumentException if parallelism less than or |
397 |
< |
* equal to zero, or greater than implementation limit. |
397 |
> |
* equal to zero, or greater than implementation limit |
398 |
|
* @throws NullPointerException if factory is null |
399 |
|
* @throws SecurityException if a security manager exists and |
400 |
|
* the caller is not permitted to modify threads |
401 |
|
* because it does not hold {@link |
402 |
< |
* java.lang.RuntimePermission}<code>("modifyThread")</code>, |
402 |
> |
* java.lang.RuntimePermission}{@code ("modifyThread")} |
403 |
|
*/ |
404 |
|
public ForkJoinPool(int parallelism, ForkJoinWorkerThreadFactory factory) { |
405 |
|
if (parallelism <= 0 || parallelism > MAX_THREADS) |
420 |
|
} |
421 |
|
|
422 |
|
/** |
423 |
< |
* Create new worker using factory. |
423 |
> |
* Creates a new worker thread using factory. |
424 |
> |
* |
425 |
|
* @param index the index to assign worker |
426 |
|
* @return new worker, or null of factory failed |
427 |
|
*/ |
440 |
|
} |
441 |
|
|
442 |
|
/** |
443 |
< |
* Return a good size for worker array given pool size. |
443 |
> |
* Returns a good size for worker array given pool size. |
444 |
|
* Currently requires size to be a power of two. |
445 |
|
*/ |
446 |
< |
private static int arraySizeFor(int ps) { |
447 |
< |
return ps <= 1? 1 : (1 << (32 - Integer.numberOfLeadingZeros(ps-1))); |
446 |
> |
private static int arraySizeFor(int poolSize) { |
447 |
> |
return (poolSize <= 1) ? 1 : |
448 |
> |
(1 << (32 - Integer.numberOfLeadingZeros(poolSize-1))); |
449 |
|
} |
450 |
|
|
451 |
|
/** |
452 |
< |
* Create or resize array if necessary to hold newLength. |
453 |
< |
* Call only under exclusion |
452 |
> |
* Creates or resizes array if necessary to hold newLength. |
453 |
> |
* Call only under exclusion. |
454 |
> |
* |
455 |
|
* @return the array |
456 |
|
*/ |
457 |
|
private ForkJoinWorkerThread[] ensureWorkerArrayCapacity(int newLength) { |
465 |
|
} |
466 |
|
|
467 |
|
/** |
468 |
< |
* Try to shrink workers into smaller array after one or more terminate |
468 |
> |
* Tries to shrink workers into smaller array after one or more terminate. |
469 |
|
*/ |
470 |
|
private void tryShrinkWorkerArray() { |
471 |
|
ForkJoinWorkerThread[] ws = workers; |
481 |
|
} |
482 |
|
|
483 |
|
/** |
484 |
< |
* Initialize workers if necessary |
484 |
> |
* Initializes workers if necessary. |
485 |
|
*/ |
486 |
|
final void ensureWorkerInitialization() { |
487 |
|
ForkJoinWorkerThread[] ws = workers; |
548 |
|
* Common code for execute, invoke and submit |
549 |
|
*/ |
550 |
|
private <T> void doSubmit(ForkJoinTask<T> task) { |
551 |
+ |
if (task == null) |
552 |
+ |
throw new NullPointerException(); |
553 |
|
if (isShutdown()) |
554 |
|
throw new RejectedExecutionException(); |
555 |
|
if (workers == null) |
559 |
|
} |
560 |
|
|
561 |
|
/** |
562 |
< |
* Performs the given task; returning its result upon completion |
562 |
> |
* Performs the given task, returning its result upon completion. |
563 |
> |
* |
564 |
|
* @param task the task |
565 |
|
* @return the task's result |
566 |
|
* @throws NullPointerException if task is null |
573 |
|
|
574 |
|
/** |
575 |
|
* Arranges for (asynchronous) execution of the given task. |
576 |
+ |
* |
577 |
|
* @param task the task |
578 |
|
* @throws NullPointerException if task is null |
579 |
|
* @throws RejectedExecutionException if pool is shut down |
585 |
|
// AbstractExecutorService methods |
586 |
|
|
587 |
|
public void execute(Runnable task) { |
588 |
< |
doSubmit(new AdaptedRunnable<Void>(task, null)); |
588 |
> |
ForkJoinTask<?> job; |
589 |
> |
if (task instanceof AdaptedCallable) // avoid re-wrap |
590 |
> |
job = (AdaptedCallable<?>)task; |
591 |
> |
else if (task instanceof AdaptedRunnable) |
592 |
> |
job = (AdaptedRunnable<?>)task; |
593 |
> |
else |
594 |
> |
job = new AdaptedRunnable<Void>(task, null); |
595 |
> |
doSubmit(job); |
596 |
|
} |
597 |
|
|
598 |
|
public <T> ForkJoinTask<T> submit(Callable<T> task) { |
608 |
|
} |
609 |
|
|
610 |
|
public ForkJoinTask<?> submit(Runnable task) { |
611 |
< |
ForkJoinTask<Void> job = new AdaptedRunnable<Void>(task, null); |
611 |
> |
ForkJoinTask<?> job; |
612 |
> |
if (task instanceof AdaptedCallable) // avoid re-wrap |
613 |
> |
job = (AdaptedCallable<?>)task; |
614 |
> |
else if (task instanceof AdaptedRunnable) |
615 |
> |
job = (AdaptedRunnable<?>)task; |
616 |
> |
else |
617 |
> |
job = new AdaptedRunnable<Void>(task, null); |
618 |
|
doSubmit(job); |
619 |
|
return job; |
620 |
|
} |
621 |
|
|
622 |
|
/** |
623 |
+ |
* Submits a ForkJoinTask for execution. |
624 |
+ |
* |
625 |
+ |
* @param task the task to submit |
626 |
+ |
* @return the task |
627 |
+ |
* @throws RejectedExecutionException if the task cannot be |
628 |
+ |
* scheduled for execution |
629 |
+ |
* @throws NullPointerException if the task is null |
630 |
+ |
*/ |
631 |
+ |
public <T> ForkJoinTask<T> submit(ForkJoinTask<T> task) { |
632 |
+ |
doSubmit(task); |
633 |
+ |
return task; |
634 |
+ |
} |
635 |
+ |
|
636 |
+ |
/** |
637 |
|
* Adaptor for Runnables. This implements RunnableFuture |
638 |
< |
* to be compliant with AbstractExecutorService constraints |
638 |
> |
* to be compliant with AbstractExecutorService constraints. |
639 |
|
*/ |
640 |
|
static final class AdaptedRunnable<T> extends ForkJoinTask<T> |
641 |
|
implements RunnableFuture<T> { |
655 |
|
return true; |
656 |
|
} |
657 |
|
public void run() { invoke(); } |
658 |
+ |
private static final long serialVersionUID = 5232453952276885070L; |
659 |
|
} |
660 |
|
|
661 |
|
/** |
684 |
|
} |
685 |
|
} |
686 |
|
public void run() { invoke(); } |
687 |
+ |
private static final long serialVersionUID = 2838392045355241008L; |
688 |
|
} |
689 |
|
|
690 |
|
public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) { |
691 |
< |
ArrayList<ForkJoinTask<T>> ts = |
691 |
> |
ArrayList<ForkJoinTask<T>> forkJoinTasks = |
692 |
|
new ArrayList<ForkJoinTask<T>>(tasks.size()); |
693 |
< |
for (Callable<T> c : tasks) |
694 |
< |
ts.add(new AdaptedCallable<T>(c)); |
695 |
< |
invoke(new InvokeAll<T>(ts)); |
696 |
< |
return (List<Future<T>>)(List)ts; |
693 |
> |
for (Callable<T> task : tasks) |
694 |
> |
forkJoinTasks.add(new AdaptedCallable<T>(task)); |
695 |
> |
invoke(new InvokeAll<T>(forkJoinTasks)); |
696 |
> |
|
697 |
> |
@SuppressWarnings({"unchecked", "rawtypes"}) |
698 |
> |
List<Future<T>> futures = (List<Future<T>>) (List) forkJoinTasks; |
699 |
> |
return futures; |
700 |
|
} |
701 |
|
|
702 |
|
static final class InvokeAll<T> extends RecursiveAction { |
703 |
|
final ArrayList<ForkJoinTask<T>> tasks; |
704 |
|
InvokeAll(ArrayList<ForkJoinTask<T>> tasks) { this.tasks = tasks; } |
705 |
|
public void compute() { |
706 |
< |
try { invokeAll(tasks); } catch(Exception ignore) {} |
706 |
> |
try { invokeAll(tasks); } |
707 |
> |
catch (Exception ignore) {} |
708 |
|
} |
709 |
+ |
private static final long serialVersionUID = -7914297376763021607L; |
710 |
|
} |
711 |
|
|
712 |
|
// Configuration and status settings and queries |
713 |
|
|
714 |
|
/** |
715 |
< |
* Returns the factory used for constructing new workers |
715 |
> |
* Returns the factory used for constructing new workers. |
716 |
|
* |
717 |
|
* @return the factory used for constructing new workers |
718 |
|
*/ |
723 |
|
/** |
724 |
|
* Returns the handler for internal worker threads that terminate |
725 |
|
* due to unrecoverable errors encountered while executing tasks. |
726 |
+ |
* |
727 |
|
* @return the handler, or null if none |
728 |
|
*/ |
729 |
|
public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() { |
749 |
|
* @throws SecurityException if a security manager exists and |
750 |
|
* the caller is not permitted to modify threads |
751 |
|
* because it does not hold {@link |
752 |
< |
* java.lang.RuntimePermission}<code>("modifyThread")</code>, |
752 |
> |
* java.lang.RuntimePermission}{@code ("modifyThread")} |
753 |
|
*/ |
754 |
|
public Thread.UncaughtExceptionHandler |
755 |
|
setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler h) { |
776 |
|
|
777 |
|
|
778 |
|
/** |
779 |
< |
* Sets the target paralleism level of this pool. |
779 |
> |
* Sets the target parallelism level of this pool. |
780 |
> |
* |
781 |
|
* @param parallelism the target parallelism |
782 |
|
* @throws IllegalArgumentException if parallelism less than or |
783 |
< |
* equal to zero or greater than maximum size bounds. |
783 |
> |
* equal to zero or greater than maximum size bounds |
784 |
|
* @throws SecurityException if a security manager exists and |
785 |
|
* the caller is not permitted to modify threads |
786 |
|
* because it does not hold {@link |
787 |
< |
* java.lang.RuntimePermission}<code>("modifyThread")</code>, |
787 |
> |
* java.lang.RuntimePermission}{@code ("modifyThread")} |
788 |
|
*/ |
789 |
|
public void setParallelism(int parallelism) { |
790 |
|
checkPermission(); |
819 |
|
/** |
820 |
|
* Returns the number of worker threads that have started but not |
821 |
|
* yet terminated. This result returned by this method may differ |
822 |
< |
* from <code>getParallelism</code> when threads are created to |
822 |
> |
* from {@code getParallelism} when threads are created to |
823 |
|
* maintain parallelism when others are cooperatively blocked. |
824 |
|
* |
825 |
|
* @return the number of worker threads |
831 |
|
/** |
832 |
|
* Returns the maximum number of threads allowed to exist in the |
833 |
|
* pool, even if there are insufficient unblocked running threads. |
834 |
+ |
* |
835 |
|
* @return the maximum |
836 |
|
*/ |
837 |
|
public int getMaximumPoolSize() { |
843 |
|
* pool, even if there are insufficient unblocked running threads. |
844 |
|
* Setting this value has no effect on current pool size. It |
845 |
|
* controls construction of new threads. |
846 |
+ |
* |
847 |
|
* @throws IllegalArgumentException if negative or greater then |
848 |
< |
* internal implementation limit. |
848 |
> |
* internal implementation limit |
849 |
|
*/ |
850 |
|
public void setMaximumPoolSize(int newMax) { |
851 |
|
if (newMax < 0 || newMax > MAX_THREADS) |
858 |
|
* Returns true if this pool dynamically maintains its target |
859 |
|
* parallelism level. If false, new threads are added only to |
860 |
|
* avoid possible starvation. |
861 |
< |
* This setting is by default true; |
861 |
> |
* This setting is by default true. |
862 |
> |
* |
863 |
|
* @return true if maintains parallelism |
864 |
|
*/ |
865 |
|
public boolean getMaintainsParallelism() { |
870 |
|
* Sets whether this pool dynamically maintains its target |
871 |
|
* parallelism level. If false, new threads are added only to |
872 |
|
* avoid possible starvation. |
873 |
+ |
* |
874 |
|
* @param enable true to maintains parallelism |
875 |
|
*/ |
876 |
|
public void setMaintainsParallelism(boolean enable) { |
884 |
|
* worker threads only process asynchronous tasks. This method is |
885 |
|
* designed to be invoked only when pool is quiescent, and |
886 |
|
* typically only before any tasks are submitted. The effects of |
887 |
< |
* invocations at ather times may be unpredictable. |
887 |
> |
* invocations at other times may be unpredictable. |
888 |
|
* |
889 |
|
* @param async if true, use locally FIFO scheduling |
890 |
< |
* @return the previous mode. |
890 |
> |
* @return the previous mode |
891 |
|
*/ |
892 |
|
public boolean setAsyncMode(boolean async) { |
893 |
|
boolean oldMode = locallyFifo; |
905 |
|
|
906 |
|
/** |
907 |
|
* Returns true if this pool uses local first-in-first-out |
908 |
< |
* scheduling mode for forked tasks that are never joined. |
908 |
> |
* scheduling mode for forked tasks that are never joined. |
909 |
|
* |
910 |
< |
* @return true if this pool uses async mode. |
910 |
> |
* @return true if this pool uses async mode |
911 |
|
*/ |
912 |
|
public boolean getAsyncMode() { |
913 |
|
return locallyFifo; |
928 |
|
* Returns an estimate of the number of threads that are currently |
929 |
|
* stealing or executing tasks. This method may overestimate the |
930 |
|
* number of active threads. |
931 |
< |
* @return the number of active threads. |
931 |
> |
* |
932 |
> |
* @return the number of active threads |
933 |
|
*/ |
934 |
|
public int getActiveThreadCount() { |
935 |
|
return activeCountOf(runControl); |
939 |
|
* Returns an estimate of the number of threads that are currently |
940 |
|
* idle waiting for tasks. This method may underestimate the |
941 |
|
* number of idle threads. |
942 |
< |
* @return the number of idle threads. |
942 |
> |
* |
943 |
> |
* @return the number of idle threads |
944 |
|
*/ |
945 |
|
final int getIdleThreadCount() { |
946 |
|
int c = runningCountOf(workerCounts) - activeCountOf(runControl); |
947 |
< |
return (c <= 0)? 0 : c; |
947 |
> |
return (c <= 0) ? 0 : c; |
948 |
|
} |
949 |
|
|
950 |
|
/** |
951 |
|
* Returns true if all worker threads are currently idle. An idle |
952 |
|
* worker is one that cannot obtain a task to execute because none |
953 |
|
* are available to steal from other threads, and there are no |
954 |
< |
* pending submissions to the pool. This method is conservative: |
955 |
< |
* It might not return true immediately upon idleness of all |
954 |
> |
* pending submissions to the pool. This method is conservative; |
955 |
> |
* it might not return true immediately upon idleness of all |
956 |
|
* threads, but will eventually become true if threads remain |
957 |
|
* inactive. |
958 |
+ |
* |
959 |
|
* @return true if all threads are currently idle |
960 |
|
*/ |
961 |
|
public boolean isQuiescent() { |
967 |
|
* one thread's work queue by another. The reported value |
968 |
|
* underestimates the actual total number of steals when the pool |
969 |
|
* is not quiescent. This value may be useful for monitoring and |
970 |
< |
* tuning fork/join programs: In general, steal counts should be |
970 |
> |
* tuning fork/join programs: in general, steal counts should be |
971 |
|
* high enough to keep threads busy, but low enough to avoid |
972 |
|
* overhead and contention across threads. |
973 |
< |
* @return the number of steals. |
973 |
> |
* |
974 |
> |
* @return the number of steals |
975 |
|
*/ |
976 |
|
public long getStealCount() { |
977 |
|
return stealCount.get(); |
978 |
|
} |
979 |
|
|
980 |
|
/** |
981 |
< |
* Accumulate steal count from a worker. Call only |
982 |
< |
* when worker known to be idle. |
981 |
> |
* Accumulates steal count from a worker. |
982 |
> |
* Call only when worker known to be idle. |
983 |
|
*/ |
984 |
|
private void updateStealCount(ForkJoinWorkerThread w) { |
985 |
|
int sc = w.getAndClearStealCount(); |
994 |
|
* an approximation, obtained by iterating across all threads in |
995 |
|
* the pool. This method may be useful for tuning task |
996 |
|
* granularities. |
997 |
< |
* @return the number of queued tasks. |
997 |
> |
* |
998 |
> |
* @return the number of queued tasks |
999 |
|
*/ |
1000 |
|
public long getQueuedTaskCount() { |
1001 |
|
long count = 0; |
1014 |
|
* Returns an estimate of the number tasks submitted to this pool |
1015 |
|
* that have not yet begun executing. This method takes time |
1016 |
|
* proportional to the number of submissions. |
1017 |
< |
* @return the number of queued submissions. |
1017 |
> |
* |
1018 |
> |
* @return the number of queued submissions |
1019 |
|
*/ |
1020 |
|
public int getQueuedSubmissionCount() { |
1021 |
|
return submissionQueue.size(); |
1024 |
|
/** |
1025 |
|
* Returns true if there are any tasks submitted to this pool |
1026 |
|
* that have not yet begun executing. |
1027 |
< |
* @return <code>true</code> if there are any queued submissions. |
1027 |
> |
* |
1028 |
> |
* @return {@code true} if there are any queued submissions |
1029 |
|
*/ |
1030 |
|
public boolean hasQueuedSubmissions() { |
1031 |
|
return !submissionQueue.isEmpty(); |
1035 |
|
* Removes and returns the next unexecuted submission if one is |
1036 |
|
* available. This method may be useful in extensions to this |
1037 |
|
* class that re-assign work in systems with multiple pools. |
1038 |
+ |
* |
1039 |
|
* @return the next submission, or null if none |
1040 |
|
*/ |
1041 |
|
protected ForkJoinTask<?> pollSubmission() { |
1046 |
|
* Removes all available unexecuted submitted and forked tasks |
1047 |
|
* from scheduling queues and adds them to the given collection, |
1048 |
|
* without altering their execution status. These may include |
1049 |
< |
* artifically generated or wrapped tasks. This method id designed |
1049 |
> |
* artificially generated or wrapped tasks. This method is designed |
1050 |
|
* to be invoked only when the pool is known to be |
1051 |
|
* quiescent. Invocations at other times may not remove all |
1052 |
|
* tasks. A failure encountered while attempting to add elements |
1053 |
< |
* to collection <tt>c</tt> may result in elements being in |
1053 |
> |
* to collection {@code c} may result in elements being in |
1054 |
|
* neither, either or both collections when the associated |
1055 |
|
* exception is thrown. The behavior of this operation is |
1056 |
|
* undefined if the specified collection is modified while the |
1057 |
|
* operation is in progress. |
1058 |
+ |
* |
1059 |
|
* @param c the collection to transfer elements into |
1060 |
|
* @return the number of elements transferred |
1061 |
|
*/ |
1116 |
|
* Invocation has no additional effect if already shut down. |
1117 |
|
* Tasks that are in the process of being submitted concurrently |
1118 |
|
* during the course of this method may or may not be rejected. |
1119 |
+ |
* |
1120 |
|
* @throws SecurityException if a security manager exists and |
1121 |
|
* the caller is not permitted to modify threads |
1122 |
|
* because it does not hold {@link |
1123 |
< |
* java.lang.RuntimePermission}<code>("modifyThread")</code>, |
1123 |
> |
* java.lang.RuntimePermission}{@code ("modifyThread")} |
1124 |
|
*/ |
1125 |
|
public void shutdown() { |
1126 |
|
checkPermission(); |
1136 |
|
* method may or may not be rejected. Unlike some other executors, |
1137 |
|
* this method cancels rather than collects non-executed tasks |
1138 |
|
* upon termination, so always returns an empty list. However, you |
1139 |
< |
* can use method <code>drainTasksTo</code> before invoking this |
1139 |
> |
* can use method {@code drainTasksTo} before invoking this |
1140 |
|
* method to transfer unexecuted tasks to another collection. |
1141 |
+ |
* |
1142 |
|
* @return an empty list |
1143 |
|
* @throws SecurityException if a security manager exists and |
1144 |
|
* the caller is not permitted to modify threads |
1145 |
|
* because it does not hold {@link |
1146 |
< |
* java.lang.RuntimePermission}<code>("modifyThread")</code>, |
1146 |
> |
* java.lang.RuntimePermission}{@code ("modifyThread")} |
1147 |
|
*/ |
1148 |
|
public List<Runnable> shutdownNow() { |
1149 |
|
checkPermission(); |
1152 |
|
} |
1153 |
|
|
1154 |
|
/** |
1155 |
< |
* Returns <code>true</code> if all tasks have completed following shut down. |
1155 |
> |
* Returns {@code true} if all tasks have completed following shut down. |
1156 |
|
* |
1157 |
< |
* @return <code>true</code> if all tasks have completed following shut down |
1157 |
> |
* @return {@code true} if all tasks have completed following shut down |
1158 |
|
*/ |
1159 |
|
public boolean isTerminated() { |
1160 |
|
return runStateOf(runControl) == TERMINATED; |
1161 |
|
} |
1162 |
|
|
1163 |
|
/** |
1164 |
< |
* Returns <code>true</code> if the process of termination has |
1164 |
> |
* Returns {@code true} if the process of termination has |
1165 |
|
* commenced but possibly not yet completed. |
1166 |
|
* |
1167 |
< |
* @return <code>true</code> if terminating |
1167 |
> |
* @return {@code true} if terminating |
1168 |
|
*/ |
1169 |
|
public boolean isTerminating() { |
1170 |
|
return runStateOf(runControl) >= TERMINATING; |
1171 |
|
} |
1172 |
|
|
1173 |
|
/** |
1174 |
< |
* Returns <code>true</code> if this pool has been shut down. |
1174 |
> |
* Returns {@code true} if this pool has been shut down. |
1175 |
|
* |
1176 |
< |
* @return <code>true</code> if this pool has been shut down |
1176 |
> |
* @return {@code true} if this pool has been shut down |
1177 |
|
*/ |
1178 |
|
public boolean isShutdown() { |
1179 |
|
return runStateOf(runControl) >= SHUTDOWN; |
1186 |
|
* |
1187 |
|
* @param timeout the maximum time to wait |
1188 |
|
* @param unit the time unit of the timeout argument |
1189 |
< |
* @return <code>true</code> if this executor terminated and |
1190 |
< |
* <code>false</code> if the timeout elapsed before termination |
1189 |
> |
* @return {@code true} if this executor terminated and |
1190 |
> |
* {@code false} if the timeout elapsed before termination |
1191 |
|
* @throws InterruptedException if interrupted while waiting |
1192 |
|
*/ |
1193 |
|
public boolean awaitTermination(long timeout, TimeUnit unit) |
1211 |
|
// Shutdown and termination support |
1212 |
|
|
1213 |
|
/** |
1214 |
< |
* Callback from terminating worker. Null out the corresponding |
1215 |
< |
* workers slot, and if terminating, try to terminate, else try to |
1216 |
< |
* shrink workers array. |
1214 |
> |
* Callback from terminating worker. Nulls out the corresponding |
1215 |
> |
* workers slot, and if terminating, tries to terminate; else |
1216 |
> |
* tries to shrink workers array. |
1217 |
> |
* |
1218 |
|
* @param w the worker |
1219 |
|
*/ |
1220 |
|
final void workerTerminated(ForkJoinWorkerThread w) { |
1245 |
|
} |
1246 |
|
|
1247 |
|
/** |
1248 |
< |
* Initiate termination. |
1248 |
> |
* Initiates termination. |
1249 |
|
*/ |
1250 |
|
private void terminate() { |
1251 |
|
if (transitionRunStateTo(TERMINATING)) { |
1260 |
|
} |
1261 |
|
|
1262 |
|
/** |
1263 |
< |
* Possibly terminate when on shutdown state |
1263 |
> |
* Possibly terminates when on shutdown state. |
1264 |
|
*/ |
1265 |
|
private void terminateOnShutdown() { |
1266 |
|
if (!hasQueuedSubmissions() && canTerminateOnShutdown(runControl)) |
1268 |
|
} |
1269 |
|
|
1270 |
|
/** |
1271 |
< |
* Clear out and cancel submissions |
1271 |
> |
* Clears out and cancels submissions. |
1272 |
|
*/ |
1273 |
|
private void cancelQueuedSubmissions() { |
1274 |
|
ForkJoinTask<?> task; |
1277 |
|
} |
1278 |
|
|
1279 |
|
/** |
1280 |
< |
* Clean out worker queues. |
1280 |
> |
* Cleans out worker queues. |
1281 |
|
*/ |
1282 |
|
private void cancelQueuedWorkerTasks() { |
1283 |
|
final ReentrantLock lock = this.workerLock; |
1297 |
|
} |
1298 |
|
|
1299 |
|
/** |
1300 |
< |
* Set each worker's status to terminating. Requires lock to avoid |
1301 |
< |
* conflicts with add/remove |
1300 |
> |
* Sets each worker's status to terminating. Requires lock to avoid |
1301 |
> |
* conflicts with add/remove. |
1302 |
|
*/ |
1303 |
|
private void stopAllWorkers() { |
1304 |
|
final ReentrantLock lock = this.workerLock; |
1318 |
|
} |
1319 |
|
|
1320 |
|
/** |
1321 |
< |
* Interrupt all unterminated workers. This is not required for |
1321 |
> |
* Interrupts all unterminated workers. This is not required for |
1322 |
|
* sake of internal control, but may help unstick user code during |
1323 |
|
* shutdown. |
1324 |
|
*/ |
1388 |
|
} |
1389 |
|
|
1390 |
|
/** |
1391 |
< |
* Wake up waiter, returning false if known to already |
1391 |
> |
* Wakes up waiter, returning false if known to already |
1392 |
|
*/ |
1393 |
|
boolean signal() { |
1394 |
|
ForkJoinWorkerThread t = thread; |
1400 |
|
} |
1401 |
|
|
1402 |
|
/** |
1403 |
< |
* Await release on sync |
1403 |
> |
* Awaits release on sync. |
1404 |
|
*/ |
1405 |
|
void awaitSyncRelease(ForkJoinPool p) { |
1406 |
|
while (thread != null && !p.syncIsReleasable(this)) |
1408 |
|
} |
1409 |
|
|
1410 |
|
/** |
1411 |
< |
* Await resumption as spare |
1411 |
> |
* Awaits resumption as spare. |
1412 |
|
*/ |
1413 |
|
void awaitSpareRelease() { |
1414 |
|
while (thread != null) { |
1422 |
|
* Ensures that no thread is waiting for count to advance from the |
1423 |
|
* current value of eventCount read on entry to this method, by |
1424 |
|
* releasing waiting threads if necessary. |
1425 |
+ |
* |
1426 |
|
* @return the count |
1427 |
|
*/ |
1428 |
|
final long ensureSync() { |
1444 |
|
*/ |
1445 |
|
private void signalIdleWorkers() { |
1446 |
|
long c; |
1447 |
< |
do;while (!casEventCount(c = eventCount, c+1)); |
1447 |
> |
do {} while (!casEventCount(c = eventCount, c+1)); |
1448 |
|
ensureSync(); |
1449 |
|
} |
1450 |
|
|
1451 |
|
/** |
1452 |
< |
* Signal threads waiting to poll a task. Because method sync |
1452 |
> |
* Signals threads waiting to poll a task. Because method sync |
1453 |
|
* rechecks availability, it is OK to only proceed if queue |
1454 |
|
* appears to be non-empty, and OK to skip under contention to |
1455 |
|
* increment count (since some other thread succeeded). |
1468 |
|
* Waits until event count advances from last value held by |
1469 |
|
* caller, or if excess threads, caller is resumed as spare, or |
1470 |
|
* caller or pool is terminating. Updates caller's event on exit. |
1471 |
+ |
* |
1472 |
|
* @param w the calling worker thread |
1473 |
|
*/ |
1474 |
|
final void sync(ForkJoinWorkerThread w) { |
1499 |
|
* Returns true if worker waiting on sync can proceed: |
1500 |
|
* - on signal (thread == null) |
1501 |
|
* - on event count advance (winning race to notify vs signaller) |
1502 |
< |
* - on Interrupt |
1502 |
> |
* - on interrupt |
1503 |
|
* - if the first queued node, we find work available |
1504 |
|
* If node was not signalled and event count not advanced on exit, |
1505 |
|
* then we also help advance event count. |
1506 |
+ |
* |
1507 |
|
* @return true if node can be released |
1508 |
|
*/ |
1509 |
|
final boolean syncIsReleasable(WaitQueueNode node) { |
1538 |
|
// Parallelism maintenance |
1539 |
|
|
1540 |
|
/** |
1541 |
< |
* Decrement running count; if too low, add spare. |
1541 |
> |
* Decrements running count; if too low, adds spare. |
1542 |
|
* |
1543 |
|
* Conceptually, all we need to do here is add or resume a |
1544 |
|
* spare thread when one is about to block (and remove or |
1545 |
|
* suspend it later when unblocked -- see suspendIfSpare). |
1546 |
|
* However, implementing this idea requires coping with |
1547 |
< |
* several problems: We have imperfect information about the |
1547 |
> |
* several problems: we have imperfect information about the |
1548 |
|
* states of threads. Some count updates can and usually do |
1549 |
|
* lag run state changes, despite arrangements to keep them |
1550 |
|
* accurate (for example, when possible, updating counts |
1558 |
|
* only be suspended or removed when they are idle, not |
1559 |
|
* immediately when they aren't needed. So adding threads will |
1560 |
|
* raise parallelism level for longer than necessary. Also, |
1561 |
< |
* FJ applications often enounter highly transient peaks when |
1561 |
> |
* FJ applications often encounter highly transient peaks when |
1562 |
|
* many threads are blocked joining, but for less time than it |
1563 |
|
* takes to create or resume spares. |
1564 |
|
* |
1567 |
|
* target counts, else create only to avoid starvation |
1568 |
|
* @return true if joinMe known to be done |
1569 |
|
*/ |
1570 |
< |
final boolean preJoin(ForkJoinTask<?> joinMe, boolean maintainParallelism) { |
1570 |
> |
final boolean preJoin(ForkJoinTask<?> joinMe, |
1571 |
> |
boolean maintainParallelism) { |
1572 |
|
maintainParallelism &= maintainsParallelism; // overrride |
1573 |
|
boolean dec = false; // true when running count decremented |
1574 |
|
while (spareStack == null || !tryResumeSpare(dec)) { |
1575 |
|
int counts = workerCounts; |
1576 |
< |
if (dec || (dec = casWorkerCounts(counts, --counts))) { // CAS cheat |
1576 |
> |
if (dec || (dec = casWorkerCounts(counts, --counts))) { |
1577 |
> |
// CAS cheat |
1578 |
|
if (!needSpare(counts, maintainParallelism)) |
1579 |
|
break; |
1580 |
|
if (joinMe.status < 0) |
1614 |
|
* there is apparently some work to do. This self-limiting rule |
1615 |
|
* means that the more threads that have already been added, the |
1616 |
|
* less parallelism we will tolerate before adding another. |
1617 |
+ |
* |
1618 |
|
* @param counts current worker counts |
1619 |
|
* @param maintainParallelism try to maintain parallelism |
1620 |
|
*/ |
1632 |
|
} |
1633 |
|
|
1634 |
|
/** |
1635 |
< |
* Add a spare worker if lock available and no more than the |
1636 |
< |
* expected numbers of threads exist |
1635 |
> |
* Adds a spare worker if lock available and no more than the |
1636 |
> |
* expected numbers of threads exist. |
1637 |
> |
* |
1638 |
|
* @return true if successful |
1639 |
|
*/ |
1640 |
|
private boolean tryAddSpare(int expectedCounts) { |
1667 |
|
} |
1668 |
|
|
1669 |
|
/** |
1670 |
< |
* Add the kth spare worker. On entry, pool coounts are already |
1670 |
> |
* Adds the kth spare worker. On entry, pool counts are already |
1671 |
|
* adjusted to reflect addition. |
1672 |
|
*/ |
1673 |
|
private void createAndStartSpare(int k) { |
1689 |
|
} |
1690 |
|
|
1691 |
|
/** |
1692 |
< |
* Suspend calling thread w if there are excess threads. Called |
1693 |
< |
* only from sync. Spares are enqueued in a Treiber stack |
1694 |
< |
* using the same WaitQueueNodes as barriers. They are resumed |
1695 |
< |
* mainly in preJoin, but are also woken on pool events that |
1696 |
< |
* require all threads to check run state. |
1692 |
> |
* Suspends calling thread w if there are excess threads. Called |
1693 |
> |
* only from sync. Spares are enqueued in a Treiber stack using |
1694 |
> |
* the same WaitQueueNodes as barriers. They are resumed mainly |
1695 |
> |
* in preJoin, but are also woken on pool events that require all |
1696 |
> |
* threads to check run state. |
1697 |
> |
* |
1698 |
|
* @param w the caller |
1699 |
|
*/ |
1700 |
|
private boolean suspendIfSpare(ForkJoinWorkerThread w) { |
1705 |
|
node = new WaitQueueNode(0, w); |
1706 |
|
if (casWorkerCounts(s, s-1)) { // representation-dependent |
1707 |
|
// push onto stack |
1708 |
< |
do;while (!casSpareStack(node.next = spareStack, node)); |
1708 |
> |
do {} while (!casSpareStack(node.next = spareStack, node)); |
1709 |
|
// block until released by resumeSpare |
1710 |
|
node.awaitSpareRelease(); |
1711 |
|
return true; |
1715 |
|
} |
1716 |
|
|
1717 |
|
/** |
1718 |
< |
* Try to pop and resume a spare thread. |
1718 |
> |
* Tries to pop and resume a spare thread. |
1719 |
> |
* |
1720 |
|
* @param updateCount if true, increment running count on success |
1721 |
|
* @return true if successful |
1722 |
|
*/ |
1734 |
|
} |
1735 |
|
|
1736 |
|
/** |
1737 |
< |
* Pop and resume all spare threads. Same idea as ensureSync. |
1737 |
> |
* Pops and resumes all spare threads. Same idea as ensureSync. |
1738 |
> |
* |
1739 |
|
* @return true if any spares released |
1740 |
|
*/ |
1741 |
|
private boolean resumeAllSpares() { |
1753 |
|
} |
1754 |
|
|
1755 |
|
/** |
1756 |
< |
* Pop and shutdown excessive spare threads. Call only while |
1756 |
> |
* Pops and shuts down excessive spare threads. Call only while |
1757 |
|
* holding lock. This is not guaranteed to eliminate all excess |
1758 |
|
* threads, only those suspended as spares, which are the ones |
1759 |
|
* unlikely to be needed in the future. |
1778 |
|
/** |
1779 |
|
* Interface for extending managed parallelism for tasks running |
1780 |
|
* in ForkJoinPools. A ManagedBlocker provides two methods. |
1781 |
< |
* Method <code>isReleasable</code> must return true if blocking is not |
1782 |
< |
* necessary. Method <code>block</code> blocks the current thread |
1783 |
< |
* if necessary (perhaps internally invoking isReleasable before |
1784 |
< |
* actually blocking.). |
1781 |
> |
* Method {@code isReleasable} must return true if blocking is not |
1782 |
> |
* necessary. Method {@code block} blocks the current thread if |
1783 |
> |
* necessary (perhaps internally invoking {@code isReleasable} |
1784 |
> |
* before actually blocking.). |
1785 |
> |
* |
1786 |
|
* <p>For example, here is a ManagedBlocker based on a |
1787 |
|
* ReentrantLock: |
1788 |
< |
* <pre> |
1789 |
< |
* class ManagedLocker implements ManagedBlocker { |
1790 |
< |
* final ReentrantLock lock; |
1791 |
< |
* boolean hasLock = false; |
1792 |
< |
* ManagedLocker(ReentrantLock lock) { this.lock = lock; } |
1793 |
< |
* public boolean block() { |
1794 |
< |
* if (!hasLock) |
1795 |
< |
* lock.lock(); |
1796 |
< |
* return true; |
1797 |
< |
* } |
1798 |
< |
* public boolean isReleasable() { |
1799 |
< |
* return hasLock || (hasLock = lock.tryLock()); |
1712 |
< |
* } |
1788 |
> |
* <pre> {@code |
1789 |
> |
* class ManagedLocker implements ManagedBlocker { |
1790 |
> |
* final ReentrantLock lock; |
1791 |
> |
* boolean hasLock = false; |
1792 |
> |
* ManagedLocker(ReentrantLock lock) { this.lock = lock; } |
1793 |
> |
* public boolean block() { |
1794 |
> |
* if (!hasLock) |
1795 |
> |
* lock.lock(); |
1796 |
> |
* return true; |
1797 |
> |
* } |
1798 |
> |
* public boolean isReleasable() { |
1799 |
> |
* return hasLock || (hasLock = lock.tryLock()); |
1800 |
|
* } |
1801 |
< |
* </pre> |
1801 |
> |
* }}</pre> |
1802 |
|
*/ |
1803 |
|
public static interface ManagedBlocker { |
1804 |
|
/** |
1805 |
|
* Possibly blocks the current thread, for example waiting for |
1806 |
|
* a lock or condition. |
1807 |
+ |
* |
1808 |
|
* @return true if no additional blocking is necessary (i.e., |
1809 |
< |
* if isReleasable would return true). |
1809 |
> |
* if isReleasable would return true) |
1810 |
|
* @throws InterruptedException if interrupted while waiting |
1811 |
< |
* (the method is not required to do so, but is allowe to). |
1811 |
> |
* (the method is not required to do so, but is allowed to) |
1812 |
|
*/ |
1813 |
|
boolean block() throws InterruptedException; |
1814 |
|
|
1823 |
|
* is a ForkJoinWorkerThread, this method possibly arranges for a |
1824 |
|
* spare thread to be activated if necessary to ensure parallelism |
1825 |
|
* while the current thread is blocked. If |
1826 |
< |
* <code>maintainParallelism</code> is true and the pool supports |
1826 |
> |
* {@code maintainParallelism} is true and the pool supports |
1827 |
|
* it ({@link #getMaintainsParallelism}), this method attempts to |
1828 |
< |
* maintain the pool's nominal parallelism. Otherwise if activates |
1828 |
> |
* maintain the pool's nominal parallelism. Otherwise it activates |
1829 |
|
* a thread only if necessary to avoid complete starvation. This |
1830 |
|
* option may be preferable when blockages use timeouts, or are |
1831 |
|
* almost always brief. |
1832 |
|
* |
1833 |
|
* <p> If the caller is not a ForkJoinTask, this method is behaviorally |
1834 |
|
* equivalent to |
1835 |
< |
* <pre> |
1836 |
< |
* while (!blocker.isReleasable()) |
1837 |
< |
* if (blocker.block()) |
1838 |
< |
* return; |
1839 |
< |
* </pre> |
1835 |
> |
* <pre> {@code |
1836 |
> |
* while (!blocker.isReleasable()) |
1837 |
> |
* if (blocker.block()) |
1838 |
> |
* return; |
1839 |
> |
* }</pre> |
1840 |
|
* If the caller is a ForkJoinTask, then the pool may first |
1841 |
|
* be expanded to ensure parallelism, and later adjusted. |
1842 |
|
* |
1845 |
|
* attempt to maintain the pool's nominal parallelism; otherwise |
1846 |
|
* activate a thread only if necessary to avoid complete |
1847 |
|
* starvation. |
1848 |
< |
* @throws InterruptedException if blocker.block did so. |
1848 |
> |
* @throws InterruptedException if blocker.block did so |
1849 |
|
*/ |
1850 |
|
public static void managedBlock(ManagedBlocker blocker, |
1851 |
|
boolean maintainParallelism) |
1852 |
|
throws InterruptedException { |
1853 |
|
Thread t = Thread.currentThread(); |
1854 |
< |
ForkJoinPool pool = (t instanceof ForkJoinWorkerThread? |
1855 |
< |
((ForkJoinWorkerThread)t).pool : null); |
1854 |
> |
ForkJoinPool pool = ((t instanceof ForkJoinWorkerThread) ? |
1855 |
> |
((ForkJoinWorkerThread) t).pool : null); |
1856 |
|
if (!blocker.isReleasable()) { |
1857 |
|
try { |
1858 |
|
if (pool == null || |
1867 |
|
|
1868 |
|
private static void awaitBlocker(ManagedBlocker blocker) |
1869 |
|
throws InterruptedException { |
1870 |
< |
do;while (!blocker.isReleasable() && !blocker.block()); |
1870 |
> |
do {} while (!blocker.isReleasable() && !blocker.block()); |
1871 |
|
} |
1872 |
|
|
1873 |
|
// AbstractExecutorService overrides |
1874 |
|
|
1875 |
|
protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) { |
1876 |
< |
return new AdaptedRunnable(runnable, value); |
1876 |
> |
return new AdaptedRunnable<T>(runnable, value); |
1877 |
|
} |
1878 |
|
|
1879 |
|
protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) { |
1880 |
< |
return new AdaptedCallable(callable); |
1880 |
> |
return new AdaptedCallable<T>(callable); |
1881 |
|
} |
1882 |
|
|
1883 |
|
|
1884 |
< |
// Temporary Unsafe mechanics for preliminary release |
1885 |
< |
private static Unsafe getUnsafe() throws Throwable { |
1884 |
> |
// Unsafe mechanics for jsr166y 3rd party package. |
1885 |
> |
private static sun.misc.Unsafe getUnsafe() { |
1886 |
|
try { |
1887 |
< |
return Unsafe.getUnsafe(); |
1887 |
> |
return sun.misc.Unsafe.getUnsafe(); |
1888 |
|
} catch (SecurityException se) { |
1889 |
|
try { |
1890 |
|
return java.security.AccessController.doPrivileged |
1891 |
< |
(new java.security.PrivilegedExceptionAction<Unsafe>() { |
1892 |
< |
public Unsafe run() throws Exception { |
1893 |
< |
return getUnsafePrivileged(); |
1891 |
> |
(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
1892 |
> |
public sun.misc.Unsafe run() throws Exception { |
1893 |
> |
return getUnsafeByReflection(); |
1894 |
|
}}); |
1895 |
|
} catch (java.security.PrivilegedActionException e) { |
1896 |
< |
throw e.getCause(); |
1896 |
> |
throw new RuntimeException("Could not initialize intrinsics", |
1897 |
> |
e.getCause()); |
1898 |
|
} |
1899 |
|
} |
1900 |
|
} |
1901 |
|
|
1902 |
< |
private static Unsafe getUnsafePrivileged() |
1902 |
> |
private static sun.misc.Unsafe getUnsafeByReflection() |
1903 |
|
throws NoSuchFieldException, IllegalAccessException { |
1904 |
< |
Field f = Unsafe.class.getDeclaredField("theUnsafe"); |
1904 |
> |
java.lang.reflect.Field f = |
1905 |
> |
sun.misc.Unsafe.class.getDeclaredField("theUnsafe"); |
1906 |
|
f.setAccessible(true); |
1907 |
< |
return (Unsafe) f.get(null); |
1907 |
> |
return (sun.misc.Unsafe) f.get(null); |
1908 |
|
} |
1909 |
|
|
1910 |
< |
private static long fieldOffset(String fieldName) |
1821 |
< |
throws NoSuchFieldException { |
1822 |
< |
return _unsafe.objectFieldOffset |
1823 |
< |
(ForkJoinPool.class.getDeclaredField(fieldName)); |
1824 |
< |
} |
1825 |
< |
|
1826 |
< |
static final Unsafe _unsafe; |
1827 |
< |
static final long eventCountOffset; |
1828 |
< |
static final long workerCountsOffset; |
1829 |
< |
static final long runControlOffset; |
1830 |
< |
static final long syncStackOffset; |
1831 |
< |
static final long spareStackOffset; |
1832 |
< |
|
1833 |
< |
static { |
1910 |
> |
private static long fieldOffset(String fieldName, Class<?> klazz) { |
1911 |
|
try { |
1912 |
< |
_unsafe = getUnsafe(); |
1913 |
< |
eventCountOffset = fieldOffset("eventCount"); |
1914 |
< |
workerCountsOffset = fieldOffset("workerCounts"); |
1915 |
< |
runControlOffset = fieldOffset("runControl"); |
1916 |
< |
syncStackOffset = fieldOffset("syncStack"); |
1917 |
< |
spareStackOffset = fieldOffset("spareStack"); |
1841 |
< |
} catch (Throwable e) { |
1842 |
< |
throw new RuntimeException("Could not initialize intrinsics", e); |
1912 |
> |
return UNSAFE.objectFieldOffset(klazz.getDeclaredField(fieldName)); |
1913 |
> |
} catch (NoSuchFieldException e) { |
1914 |
> |
// Convert Exception to Error |
1915 |
> |
NoSuchFieldError error = new NoSuchFieldError(fieldName); |
1916 |
> |
error.initCause(e); |
1917 |
> |
throw error; |
1918 |
|
} |
1919 |
|
} |
1920 |
|
|
1921 |
+ |
private static final sun.misc.Unsafe UNSAFE = getUnsafe(); |
1922 |
+ |
static final long eventCountOffset = |
1923 |
+ |
fieldOffset("eventCount", ForkJoinPool.class); |
1924 |
+ |
static final long workerCountsOffset = |
1925 |
+ |
fieldOffset("workerCounts", ForkJoinPool.class); |
1926 |
+ |
static final long runControlOffset = |
1927 |
+ |
fieldOffset("runControl", ForkJoinPool.class); |
1928 |
+ |
static final long syncStackOffset = |
1929 |
+ |
fieldOffset("syncStack",ForkJoinPool.class); |
1930 |
+ |
static final long spareStackOffset = |
1931 |
+ |
fieldOffset("spareStack", ForkJoinPool.class); |
1932 |
+ |
|
1933 |
|
private boolean casEventCount(long cmp, long val) { |
1934 |
< |
return _unsafe.compareAndSwapLong(this, eventCountOffset, cmp, val); |
1934 |
> |
return UNSAFE.compareAndSwapLong(this, eventCountOffset, cmp, val); |
1935 |
|
} |
1936 |
|
private boolean casWorkerCounts(int cmp, int val) { |
1937 |
< |
return _unsafe.compareAndSwapInt(this, workerCountsOffset, cmp, val); |
1937 |
> |
return UNSAFE.compareAndSwapInt(this, workerCountsOffset, cmp, val); |
1938 |
|
} |
1939 |
|
private boolean casRunControl(int cmp, int val) { |
1940 |
< |
return _unsafe.compareAndSwapInt(this, runControlOffset, cmp, val); |
1940 |
> |
return UNSAFE.compareAndSwapInt(this, runControlOffset, cmp, val); |
1941 |
|
} |
1942 |
|
private boolean casSpareStack(WaitQueueNode cmp, WaitQueueNode val) { |
1943 |
< |
return _unsafe.compareAndSwapObject(this, spareStackOffset, cmp, val); |
1943 |
> |
return UNSAFE.compareAndSwapObject(this, spareStackOffset, cmp, val); |
1944 |
|
} |
1945 |
|
private boolean casBarrierStack(WaitQueueNode cmp, WaitQueueNode val) { |
1946 |
< |
return _unsafe.compareAndSwapObject(this, syncStackOffset, cmp, val); |
1946 |
> |
return UNSAFE.compareAndSwapObject(this, syncStackOffset, cmp, val); |
1947 |
|
} |
1948 |
|
} |