[ViewVC] Diff of: jsr166/jsr166/src/jsr166y/ForkJoinPool.java

Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.53 by dl, Mon Apr 5 15:52:26 2010 UTC vs.
Revision 1.85 by dl, Sun Nov 21 13:55:04 2010 UTC

#	Line 6 \| Line 6
6
7		package jsr166y;
8
9	–	import java.util.concurrent.*;
10	–
9		import java.util.ArrayList;
10		import java.util.Arrays;
11		import java.util.Collection;
12		import java.util.Collections;
13		import java.util.List;
14	+	import java.util.concurrent.AbstractExecutorService;
15	+	import java.util.concurrent.Callable;
16	+	import java.util.concurrent.ExecutorService;
17	+	import java.util.concurrent.Future;
18	+	import java.util.concurrent.RejectedExecutionException;
19	+	import java.util.concurrent.RunnableFuture;
20	+	import java.util.concurrent.TimeUnit;
21	+	import java.util.concurrent.TimeoutException;
22	+	import java.util.concurrent.atomic.AtomicInteger;
23		import java.util.concurrent.locks.LockSupport;
24		import java.util.concurrent.locks.ReentrantLock;
18	–	import java.util.concurrent.atomic.AtomicInteger;
19	–	import java.util.concurrent.CountDownLatch;
25
26		/**
27		* An {@link ExecutorService} for running {@link ForkJoinTask}s.
28		* A {@code ForkJoinPool} provides the entry point for submissions
29	<	* from non-{@code ForkJoinTask}s, as well as management and
29	>	* from non-{@code ForkJoinTask} clients, as well as management and
30		* monitoring operations.
31		*
32		* <p>A {@code ForkJoinPool} differs from other kinds of {@link
#	Line 30 \| Line 35 \| import java.util.concurrent.CountDownLat
35		* execute subtasks created by other active tasks (eventually blocking
36		* waiting for work if none exist). This enables efficient processing
37		* when most tasks spawn other subtasks (as do most {@code
38	<	* ForkJoinTask}s). A {@code ForkJoinPool} may also be used for mixed
39	<	* execution of some plain {@code Runnable}- or {@code Callable}-
40	<	* based activities along with {@code ForkJoinTask}s. When setting
36	<	* {@linkplain #setAsyncMode async mode}, a {@code ForkJoinPool} may
37	<	* also be appropriate for use with fine-grained tasks of any form
38	<	* that are never joined. Otherwise, other {@code ExecutorService}
39	<	* implementations are typically more appropriate choices.
38	>	* ForkJoinTask}s). When setting <em>asyncMode</em> to true in
39	>	* constructors, {@code ForkJoinPool}s may also be appropriate for use
40	>	* with event-style tasks that are never joined.
41		*
42		* <p>A {@code ForkJoinPool} is constructed with a given target
43		* parallelism level; by default, equal to the number of available
44	<	* processors. Unless configured otherwise via {@link
45	<	* #setMaintainsParallelism}, the pool attempts to maintain this
46	<	* number of active (or available) threads by dynamically adding,
47	<	* suspending, or resuming internal worker threads, even if some tasks
48	<	* are stalled waiting to join others. However, no such adjustments
49	<	* are performed in the face of blocked IO or other unmanaged
50	<	* synchronization. The nested {@link ManagedBlocker} interface
50	<	* enables extension of the kinds of synchronization accommodated.
51	<	* The target parallelism level may also be changed dynamically
52	<	* ({@link #setParallelism}). The total number of threads may be
53	<	* limited using method {@link #setMaximumPoolSize}, in which case it
54	<	* may become possible for the activities of a pool to stall due to
55	<	* the lack of available threads to process new tasks. When the pool
56	<	* is executing tasks, these and other configuration setting methods
57	<	* may only gradually affect actual pool sizes. It is normally best
58	<	* practice to invoke these methods only when the pool is known to be
59	<	* quiescent.
44	>	* processors. The pool attempts to maintain enough active (or
45	>	* available) threads by dynamically adding, suspending, or resuming
46	>	* internal worker threads, even if some tasks are stalled waiting to
47	>	* join others. However, no such adjustments are guaranteed in the
48	>	* face of blocked IO or other unmanaged synchronization. The nested
49	>	* {@link ManagedBlocker} interface enables extension of the kinds of
50	>	* synchronization accommodated.
51		*
52		* <p>In addition to execution and lifecycle control methods, this
53		* class provides status check methods (for example
#	Line 65 \| Line 56 \| import java.util.concurrent.CountDownLat
56		* {@link #toString} returns indications of pool state in a
57		* convenient form for informal monitoring.
58		*
59	+	* <p> As is the case with other ExecutorServices, there are three
60	+	* main task execution methods summarized in the following
61	+	* table. These are designed to be used by clients not already engaged
62	+	* in fork/join computations in the current pool. The main forms of
63	+	* these methods accept instances of {@code ForkJoinTask}, but
64	+	* overloaded forms also allow mixed execution of plain {@code
65	+	* Runnable}- or {@code Callable}- based activities as well. However,
66	+	* tasks that are already executing in a pool should normally
67	+	* <em>NOT</em> use these pool execution methods, but instead use the
68	+	* within-computation forms listed in the table.
69	+	*
70	+	* <table BORDER CELLPADDING=3 CELLSPACING=1>
71	+	* <tr>
72	+	* <td></td>
73	+	* <td ALIGN=CENTER> <b>Call from non-fork/join clients</b></td>
74	+	* <td ALIGN=CENTER> <b>Call from within fork/join computations</b></td>
75	+	* </tr>
76	+	* <tr>
77	+	* <td> <b>Arrange async execution</td>
78	+	* <td> {@link #execute(ForkJoinTask)}</td>
79	+	* <td> {@link ForkJoinTask#fork}</td>
80	+	* </tr>
81	+	* <tr>
82	+	* <td> <b>Await and obtain result</td>
83	+	* <td> {@link #invoke(ForkJoinTask)}</td>
84	+	* <td> {@link ForkJoinTask#invoke}</td>
85	+	* </tr>
86	+	* <tr>
87	+	* <td> <b>Arrange exec and obtain Future</td>
88	+	* <td> {@link #submit(ForkJoinTask)}</td>
89	+	* <td> {@link ForkJoinTask#fork} (ForkJoinTasks <em>are</em> Futures)</td>
90	+	* </tr>
91	+	* </table>
92	+	*
93		* <p><b>Sample Usage.</b> Normally a single {@code ForkJoinPool} is
94		* used for all parallel task execution in a program or subsystem.
95		* Otherwise, use would not usually outweigh the construction and
#	Line 89 \| Line 114 \| import java.util.concurrent.CountDownLat
114		* {@code IllegalArgumentException}.
115		*
116		* <p>This implementation rejects submitted tasks (that is, by throwing
117	<	* {@link RejectedExecutionException}) only when the pool is shut down.
117	>	* {@link RejectedExecutionException}) only when the pool is shut down
118	>	* or internal resources have been exhausted.
119		*
120		* @since 1.7
121		* @author Doug Lea
#	Line 116 \| Line 142 \| public class ForkJoinPool extends Abstra
142		* of tasks profit from cache affinities, but others are harmed by
143		* cache pollution effects.)
144		*
145	+	* Beyond work-stealing support and essential bookkeeping, the
146	+	* main responsibility of this framework is to take actions when
147	+	* one worker is waiting to join a task stolen (or always held by)
148	+	* another. Because we are multiplexing many tasks on to a pool
149	+	* of workers, we can't just let them block (as in Thread.join).
150	+	* We also cannot just reassign the joiner's run-time stack with
151	+	* another and replace it later, which would be a form of
152	+	* "continuation", that even if possible is not necessarily a good
153	+	* idea. Given that the creation costs of most threads on most
154	+	* systems mainly surrounds setting up runtime stacks, thread
155	+	* creation and switching is usually not much more expensive than
156	+	* stack creation and switching, and is more flexible). Instead we
157	+	* combine two tactics:
158	+	*
159	+	* Helping: Arranging for the joiner to execute some task that it
160	+	* would be running if the steal had not occurred. Method
161	+	* ForkJoinWorkerThread.helpJoinTask tracks joining->stealing
162	+	* links to try to find such a task.
163	+	*
164	+	* Compensating: Unless there are already enough live threads,
165	+	* method helpMaintainParallelism() may create or
166	+	* re-activate a spare thread to compensate for blocked
167	+	* joiners until they unblock.
168	+	*
169	+	* It is impossible to keep exactly the target (parallelism)
170	+	* number of threads running at any given time. Determining
171	+	* existence of conservatively safe helping targets, the
172	+	* availability of already-created spares, and the apparent need
173	+	* to create new spares are all racy and require heuristic
174	+	* guidance, so we rely on multiple retries of each. Compensation
175	+	* occurs in slow-motion. It is triggered only upon timeouts of
176	+	* Object.wait used for joins. This reduces poor decisions that
177	+	* would otherwise be made when threads are waiting for others
178	+	* that are stalled because of unrelated activities such as
179	+	* garbage collection.
180	+	*
181	+	* The ManagedBlocker extension API can't use helping so relies
182	+	* only on compensation in method awaitBlocker.
183	+	*
184		* The main throughput advantages of work-stealing stem from
185		* decentralized control -- workers mostly steal tasks from each
186		* other. We do not want to negate this by creating bottlenecks
187	<	* implementing the management responsibilities of this class. So
188	<	* we use a collection of techniques that avoid, reduce, or cope
189	<	* well with contention. These entail several instances of
190	<	* bit-packing into CASable fields to maintain only the minimally
191	<	* required atomicity. To enable such packing, we restrict maximum
192	<	* parallelism to (1<<15)-1 (enabling twice this to fit into a 16
193	<	* bit field), which is far in excess of normal operating range.
194	<	* Even though updates to some of these bookkeeping fields do
195	<	* sometimes contend with each other, they don't normally
196	<	* cache-contend with updates to others enough to warrant memory
197	<	* padding or isolation. So they are all held as fields of
198	<	* ForkJoinPool objects. The main capabilities are as follows:
187	>	* implementing other management responsibilities. So we use a
188	>	* collection of techniques that avoid, reduce, or cope well with
189	>	* contention. These entail several instances of bit-packing into
190	>	* CASable fields to maintain only the minimally required
191	>	* atomicity. To enable such packing, we restrict maximum
192	>	* parallelism to (1<<15)-1 (enabling twice this (to accommodate
193	>	* unbalanced increments and decrements) to fit into a 16 bit
194	>	* field, which is far in excess of normal operating range. Even
195	>	* though updates to some of these bookkeeping fields do sometimes
196	>	* contend with each other, they don't normally cache-contend with
197	>	* updates to others enough to warrant memory padding or
198	>	* isolation. So they are all held as fields of ForkJoinPool
199	>	* objects. The main capabilities are as follows:
200		*
201		* 1. Creating and removing workers. Workers are recorded in the
202		* "workers" array. This is an array as opposed to some other data
#	Line 140 \| Line 206 \| public class ForkJoinPool extends Abstra
206		* (workerLock) but the array is otherwise concurrently readable,
207		* and accessed directly by workers. To simplify index-based
208		* operations, the array size is always a power of two, and all
209	<	* readers must tolerate null slots. Currently, all but the first
210	<	* worker thread creation is on-demand, triggered by task
211	<	* submissions, replacement of terminated workers, and/or
212	<	* compensation for blocked workers. However, all other support
213	<	* code is set up to work with other policies.
209	>	* readers must tolerate null slots. Currently, all worker thread
210	>	* creation is on-demand, triggered by task submissions,
211	>	* replacement of terminated workers, and/or compensation for
212	>	* blocked workers. However, all other support code is set up to
213	>	* work with other policies.
214	>	*
215	>	* To ensure that we do not hold on to worker references that
216	>	* would prevent GC, ALL accesses to workers are via indices into
217	>	* the workers array (which is one source of some of the unusual
218	>	* code constructions here). In essence, the workers array serves
219	>	* as a WeakReference mechanism. Thus for example the event queue
220	>	* stores worker indices, not worker references. Access to the
221	>	* workers in associated methods (for example releaseEventWaiters)
222	>	* must both index-check and null-check the IDs. All such accesses
223	>	* ignore bad IDs by returning out early from what they are doing,
224	>	* since this can only be associated with shutdown, in which case
225	>	* it is OK to give up. On termination, we just clobber these
226	>	* data structures without trying to use them.
227		*
228		* 2. Bookkeeping for dynamically adding and removing workers. We
229	<	* maintain a given level of parallelism (or, if
230	<	* maintainsParallelism is false, at least avoid starvation). When
152	<	* some workers are known to be blocked (on joins or via
229	>	* aim to approximately maintain the given level of parallelism.
230	>	* When some workers are known to be blocked (on joins or via
231		* ManagedBlocker), we may create or resume others to take their
232		* place until they unblock (see below). Implementing this
233		* requires counts of the number of "running" threads (i.e., those
234	<	* that are neither blocked nor artifically suspended) as well as
234	>	* that are neither blocked nor artificially suspended) as well as
235		* the total number. These two values are packed into one field,
236		* "workerCounts" because we need accurate snapshots when deciding
237	<	* to create, resume or suspend. To support these decisions,
238	<	* updates must be prospective (not retrospective). For example,
239	<	* the running count is decremented before blocking by a thread
240	<	* about to block, but incremented by the thread about to unblock
163	<	* it. (In a few cases, these prospective updates may need to be
164	<	* rolled back, for example when deciding to create a new worker
165	<	* but the thread factory fails or returns null. In these cases,
166	<	* we are no worse off wrt other decisions than we would be
167	<	* otherwise.) Updates to the workerCounts field sometimes
168	<	* transiently encounter a fair amount of contention when join
169	<	* dependencies are such that many threads block or unblock at
170	<	* about the same time. We alleviate this by sometimes bundling
171	<	* updates (for example blocking one thread on join and resuming a
172	<	* spare cancel each other out), and in most other cases
173	<	* performing an alternative action (like releasing waiters and
174	<	* finding spares; see below) as a more productive form of
175	<	* backoff.
237	>	* to create, resume or suspend. Note however that the
238	>	* correspondence of these counts to reality is not guaranteed. In
239	>	* particular updates for unblocked threads may lag until they
240	>	* actually wake up.
241		*
242		* 3. Maintaining global run state. The run state of the pool
243		* consists of a runLevel (SHUTDOWN, TERMINATING, etc) similar to
#	Line 201 \| Line 266 \| public class ForkJoinPool extends Abstra
266		* workers that previously could not find a task to now find one:
267		* Submission of a new task to the pool, or another worker pushing
268		* a task onto a previously empty queue. (We also use this
269	<	* mechanism for termination and reconfiguration actions that
269	>	* mechanism for configuration and termination actions that
270		* require wakeups of idle workers). Each worker maintains its
271		* last known event count, and blocks when a scan for work did not
272		* find a task AND its lastEventCount matches the current
#	Line 212 \| Line 277 \| public class ForkJoinPool extends Abstra
277		* a record (field nextEventWaiter) for the next waiting worker.
278		* In addition to allowing simpler decisions about need for
279		* wakeup, the event count bits in eventWaiters serve the role of
280	<	* tags to avoid ABA errors in Treiber stacks. To reduce delays
281	<	* in task diffusion, workers not otherwise occupied may invoke
282	<	* method releaseWaiters, that removes and signals (unparks)
283	<	* workers not waiting on current count. To minimize task
284	<	* production stalls associate with signalling, any worker pushing
285	<	* a task on an empty queue invokes the weaker method signalWork,
221	<	* that only releases idle workers until it detects interference
222	<	* by other threads trying to release, and lets them take
223	<	* over. The net effect is a tree-like diffusion of signals, where
224	<	* released threads and possibly others) help with unparks. To
225	<	* further reduce contention effects a bit, failed CASes to
226	<	* increment field eventCount are tolerated without retries.
280	>	* tags to avoid ABA errors in Treiber stacks. Upon any wakeup,
281	>	* released threads also try to release at most two others. The
282	>	* net effect is a tree-like diffusion of signals, where released
283	>	* threads (and possibly others) help with unparks. To further
284	>	* reduce contention effects a bit, failed CASes to increment
285	>	* field eventCount are tolerated without retries in signalWork.
286		* Conceptually they are merged into the same event, which is OK
287		* when their only purpose is to enable workers to scan for work.
288		*
289	<	* 5. Managing suspension of extra workers. When a worker is about
290	<	* to block waiting for a join (or via ManagedBlockers), we may
291	<	* create a new thread to maintain parallelism level, or at least
292	<	* avoid starvation (see below). Usually, extra threads are needed
293	<	* for only very short periods, yet join dependencies are such
294	<	* that we sometimes need them in bursts. Rather than create new
295	<	* threads each time this happens, we suspend no-longer-needed
296	<	* extra ones as "spares". For most purposes, we don't distinguish
297	<	* "extra" spare threads from normal "core" threads: On each call
298	<	* to preStep (the only point at which we can do this) a worker
299	<	* checks to see if there are now too many running workers, and if
300	<	* so, suspends itself. Methods preJoin and doBlock look for
301	<	* suspended threads to resume before considering creating a new
302	<	* replacement. We don't need a special data structure to maintain
303	<	* spares; simply scanning the workers array looking for
304	<	* worker.isSuspended() is fine because the calling thread is
305	<	* otherwise not doing anything useful anyway; we are at least as
306	<	* happy if after locating a spare, the caller doesn't actually
307	<	* block because the join is ready before we try to adjust and
308	<	* compensate. Note that this is intrinsically racy. One thread
309	<	* may become a spare at about the same time as another is
310	<	* needlessly being created. We counteract this and related slop
311	<	* in part by requiring resumed spares to immediately recheck (in
312	<	* preStep) to see whether they they should re-suspend. The only
313	<	* effective difference between "extra" and "core" threads is that
314	<	* we allow the "extra" ones to time out and die if they are not
315	<	* resumed within a keep-alive interval of a few seconds. This is
316	<	* implemented mainly within ForkJoinWorkerThread, but requires
317	<	* some coordination (isTrimmed() -- meaning killed while
318	<	* suspended) to correctly maintain pool counts.
319	<	*
320	<	* 6. Deciding when to create new workers. The main dynamic
321	<	* control in this class is deciding when to create extra threads,
322	<	* in methods preJoin and doBlock. We always need to create one
323	<	* when the number of running threads becomes zero. But because
324	<	* blocked joins are typically dependent, we don't necessarily
325	<	* need or want one-to-one replacement. Using a one-to-one
326	<	* compensation rule often leads to enough useless overhead
327	<	* creating, suspending, resuming, and/or killing threads to
328	<	* signficantly degrade throughput. We use a rule reflecting the
329	<	* idea that, the more spare threads you already have, the more
330	<	* evidence you need to create another one; where "evidence" is
331	<	* expressed as the current deficit -- target minus running
332	<	* threads. To reduce flickering and drift around target values,
333	<	* the relation is quadratic: adding a spare if (dcdc)>=(scpc)
334	<	* (where dc is deficit, sc is number of spare threads and pc is
335	<	* target parallelism.) This effectively reduces churn at the
336	<	* price of systematically undershooting target parallelism when
337	<	* many threads are blocked. However, biasing toward undeshooting
338	<	* partially compensates for the above mechanics to suspend extra
339	<	* threads, that normally lead to overshoot because we can only
281	<	* suspend workers in-between top-level actions. It also better
282	<	* copes with the fact that some of the methods in this class tend
283	<	* to never become compiled (but are interpreted), so some
284	<	* components of the entire set of controls might execute many
285	<	* times faster than others. And similarly for cases where the
286	<	* apparent lack of work is just due to GC stalls and other
287	<	* transient system activity.
288	<	*
289	<	* 7. Maintaining other configuration parameters and monitoring
290	<	* statistics. Updates to fields controlling parallelism level,
291	<	* max size, etc can only meaningfully take effect for individual
292	<	* threads upon their next top-level actions; i.e., between
293	<	* stealing/running tasks/submission, which are separated by calls
294	<	* to preStep. Memory ordering for these (assumed infrequent)
295	<	* reconfiguration calls is ensured by using reads and writes to
296	<	* volatile field workerCounts (that must be read in preStep anyway)
297	<	* as "fences" -- user-level reads are preceded by reads of
298	<	* workCounts, and writes are followed by no-op CAS to
299	<	* workerCounts. The values reported by other management and
300	<	* monitoring methods are either computed on demand, or are kept
301	<	* in fields that are only updated when threads are otherwise
302	<	* idle.
289	>	* 5. Managing suspension of extra workers. When a worker notices
290	>	* (usually upon timeout of a wait()) that there are too few
291	>	* running threads, we may create a new thread to maintain
292	>	* parallelism level, or at least avoid starvation. Usually, extra
293	>	* threads are needed for only very short periods, yet join
294	>	* dependencies are such that we sometimes need them in
295	>	* bursts. Rather than create new threads each time this happens,
296	>	* we suspend no-longer-needed extra ones as "spares". For most
297	>	* purposes, we don't distinguish "extra" spare threads from
298	>	* normal "core" threads: On each call to preStep (the only point
299	>	* at which we can do this) a worker checks to see if there are
300	>	* now too many running workers, and if so, suspends itself.
301	>	* Method helpMaintainParallelism looks for suspended threads to
302	>	* resume before considering creating a new replacement. The
303	>	* spares themselves are encoded on another variant of a Treiber
304	>	* Stack, headed at field "spareWaiters". Note that the use of
305	>	* spares is intrinsically racy. One thread may become a spare at
306	>	* about the same time as another is needlessly being created. We
307	>	* counteract this and related slop in part by requiring resumed
308	>	* spares to immediately recheck (in preStep) to see whether they
309	>	* should re-suspend.
310	>	*
311	>	* 6. Killing off unneeded workers. A timeout mechanism is used to
312	>	* shed unused workers: The oldest (first) event queue waiter uses
313	>	* a timed rather than hard wait. When this wait times out without
314	>	* a normal wakeup, it tries to shutdown any one (for convenience
315	>	* the newest) other spare or event waiter via
316	>	* tryShutdownUnusedWorker. This eventually reduces the number of
317	>	* worker threads to a minimum of one after a long enough period
318	>	* without use.
319	>	*
320	>	* 7. Deciding when to create new workers. The main dynamic
321	>	* control in this class is deciding when to create extra threads
322	>	* in method helpMaintainParallelism. We would like to keep
323	>	* exactly #parallelism threads running, which is an impossible
324	>	* task. We always need to create one when the number of running
325	>	* threads would become zero and all workers are busy. Beyond
326	>	* this, we must rely on heuristics that work well in the
327	>	* presence of transient phenomena such as GC stalls, dynamic
328	>	* compilation, and wake-up lags. These transients are extremely
329	>	* common -- we are normally trying to fully saturate the CPUs on
330	>	* a machine, so almost any activity other than running tasks
331	>	* impedes accuracy. Our main defense is to allow parallelism to
332	>	* lapse for a while during joins, and use a timeout to see if,
333	>	* after the resulting settling, there is still a need for
334	>	* additional workers. This also better copes with the fact that
335	>	* some of the methods in this class tend to never become compiled
336	>	* (but are interpreted), so some components of the entire set of
337	>	* controls might execute 100 times faster than others. And
338	>	* similarly for cases where the apparent lack of work is just due
339	>	* to GC stalls and other transient system activity.
340		*
341		* Beware that there is a lot of representation-level coupling
342		* among classes ForkJoinPool, ForkJoinWorkerThread, and
#	Line 312 \| Line 349 \| public class ForkJoinPool extends Abstra
349		*
350		* Style notes: There are lots of inline assignments (of form
351		* "while ((local = field) != 0)") which are usually the simplest
352	<	* way to ensure read orderings. Also several occurrences of the
353	<	* unusual "do {} while(!cas...)" which is the simplest way to
354	<	* force an update of a CAS'ed variable. There are also a few
355	<	* other coding oddities that help some methods perform reasonably
356	<	* even when interpreted (not compiled).
352	>	* way to ensure the required read orderings (which are sometimes
353	>	* critical). Also several occurrences of the unusual "do {}
354	>	* while (!cas...)" which is the simplest way to force an update of
355	>	* a CAS'ed variable. There are also other coding oddities that
356	>	* help some methods perform reasonably even when interpreted (not
357	>	* compiled), at the expense of some messy constructions that
358	>	* reduce byte code counts.
359		*
360		* The order of declarations in this file is: (1) statics (2)
361		* fields (along with constants used when unpacking some of them)
#	Line 345 \| Line 384 \| public class ForkJoinPool extends Abstra
384		* Default ForkJoinWorkerThreadFactory implementation; creates a
385		* new ForkJoinWorkerThread.
386		*/
387	<	static class DefaultForkJoinWorkerThreadFactory
387	>	static class DefaultForkJoinWorkerThreadFactory
388		implements ForkJoinWorkerThreadFactory {
389		public ForkJoinWorkerThread newThread(ForkJoinPool pool) {
390		return new ForkJoinWorkerThread(pool);
#	Line 384 \| Line 423 \| public class ForkJoinPool extends Abstra
423		new AtomicInteger();
424
425		/**
426	<	* Absolute bound for parallelism level. Twice this number must
427	<	* fit into a 16bit field to enable word-packing for some counts.
426	>	* The time to block in a join (see awaitJoin) before checking if
427	>	* a new worker should be (re)started to maintain parallelism
428	>	* level. The value should be short enough to maintain global
429	>	* responsiveness and progress but long enough to avoid
430	>	* counterproductive firings during GC stalls or unrelated system
431	>	* activity, and to not bog down systems with continual re-firings
432	>	* on GCs or legitimately long waits.
433		*/
434	<	private static final int MAX_THREADS = 0x7fff;
434	>	private static final long JOIN_TIMEOUT_MILLIS = 250L; // 4 per second
435	>
436	>	/**
437	>	* The wakeup interval (in nanoseconds) for the oldest worker
438	>	* waiting for an event to invoke tryShutdownUnusedWorker to
439	>	* shrink the number of workers. The exact value does not matter
440	>	* too much. It must be short enough to release resources during
441	>	* sustained periods of idleness, but not so short that threads
442	>	* are continually re-created.
443	>	*/
444	>	private static final long SHRINK_RATE_NANOS =
445	>	30L * 1000L * 1000L * 1000L; // 2 per minute
446	>
447	>	/**
448	>	* Absolute bound for parallelism level. Twice this number plus
449	>	* one (i.e., 0xfff) must fit into a 16bit field to enable
450	>	* word-packing for some counts and indices.
451	>	*/
452	>	private static final int MAX_WORKERS = 0x7fff;
453
454		/**
455		* Array holding all worker threads in the pool. Array size must
#	Line 413 \| Line 475 \| public class ForkJoinPool extends Abstra
475		/**
476		* Latch released upon termination.
477		*/
478	<	private final CountDownLatch terminationLatch;
478	>	private final Phaser termination;
479
480		/**
481		* Creation factory for worker threads.
#	Line 427 \| Line 489 \| public class ForkJoinPool extends Abstra
489		private volatile long stealCount;
490
491		/**
492	<	* Encoded record of top of treiber stack of threads waiting for
492	>	* Encoded record of top of Treiber stack of threads waiting for
493		* events. The top 32 bits contain the count being waited for. The
494	<	* bottom word contains one plus the pool index of waiting worker
495	<	* thread.
494	>	* bottom 16 bits contains one plus the pool index of waiting
495	>	* worker thread. (Bits 16-31 are unused.)
496		*/
497		private volatile long eventWaiters;
498
499		private static final int EVENT_COUNT_SHIFT = 32;
500	<	private static final long WAITER_INDEX_MASK = (1L << EVENT_COUNT_SHIFT)-1L;
500	>	private static final long WAITER_ID_MASK = (1L << 16) - 1L;
501
502		/**
503		* A counter for events that may wake up worker threads:
504		* - Submission of a new task to the pool
505		* - A worker pushing a task on an empty queue
506	<	* - termination and reconfiguration
506	>	* - termination
507		*/
508		private volatile int eventCount;
509
510		/**
511	+	* Encoded record of top of Treiber stack of spare threads waiting
512	+	* for resumption. The top 16 bits contain an arbitrary count to
513	+	* avoid ABA effects. The bottom 16bits contains one plus the pool
514	+	* index of waiting worker thread.
515	+	*/
516	+	private volatile int spareWaiters;
517	+
518	+	private static final int SPARE_COUNT_SHIFT = 16;
519	+	private static final int SPARE_ID_MASK = (1 << 16) - 1;
520	+
521	+	/**
522		* Lifecycle control. The low word contains the number of workers
523		* that are (probably) executing tasks. This value is atomically
524		* incremented before a worker gets a task to run, and decremented
525	<	* when worker has no tasks and cannot find any. Bits 16-18
525	>	* when a worker has no tasks and cannot find any. Bits 16-18
526		* contain runLevel value. When all are zero, the pool is
527		* running. Level transitions are monotonic (running -> shutdown
528		* -> terminating -> terminated) so each transition adds a bit.
529		* These are bundled together to ensure consistent read for
530		* termination checks (i.e., that runLevel is at least SHUTDOWN
531		* and active threads is zero).
532	+	*
533	+	* Notes: Most direct CASes are dependent on these bitfield
534	+	* positions. Also, this field is non-private to enable direct
535	+	* performance-sensitive CASes in ForkJoinWorkerThread.
536		*/
537	<	private volatile int runState;
537	>	volatile int runState;
538
539		// Note: The order among run level values matters.
540		private static final int RUNLEVEL_SHIFT = 16;
#	Line 465 \| Line 542 \| public class ForkJoinPool extends Abstra
542		private static final int TERMINATING = 1 << (RUNLEVEL_SHIFT + 1);
543		private static final int TERMINATED = 1 << (RUNLEVEL_SHIFT + 2);
544		private static final int ACTIVE_COUNT_MASK = (1 << RUNLEVEL_SHIFT) - 1;
468	–	private static final int ONE_ACTIVE = 1; // active update delta
545
546		/**
547		* Holds number of total (i.e., created and not yet terminated)
#	Line 474 \| Line 550 \| public class ForkJoinPool extends Abstra
550		* making decisions about creating and suspending spare
551		* threads. Updated only by CAS. Note that adding a new worker
552		* requires incrementing both counts, since workers start off in
553	<	* running state. This field is also used for memory-fencing
478	<	* configuration parameters.
553	>	* running state.
554		*/
555		private volatile int workerCounts;
556
#	Line 484 \| Line 559 \| public class ForkJoinPool extends Abstra
559		private static final int ONE_RUNNING = 1;
560		private static final int ONE_TOTAL = 1 << TOTAL_COUNT_SHIFT;
561
487	–	/*
488	–	* Fields parallelism. maxPoolSize, locallyFifo,
489	–	* maintainsParallelism, and ueh are non-volatile, but external
490	–	* reads/writes use workerCount fences to ensure visability.
491	–	*/
492	–
562		/**
563		* The target parallelism level.
564	+	* Accessed directly by ForkJoinWorkerThreads.
565		*/
566	<	private int parallelism;
497	<
498	<	/**
499	<	* The maximum allowed pool size.
500	<	*/
501	<	private int maxPoolSize;
566	>	final int parallelism;
567
568		/**
569		* True if use local fifo, not default lifo, for local polling
570	<	* Replicated by ForkJoinWorkerThreads
506	<	*/
507	<	private boolean locallyFifo;
508	<
509	<	/**
510	<	* Controls whether to add spares to maintain parallelism
570	>	* Read by, and replicated by ForkJoinWorkerThreads
571		*/
572	<	private boolean maintainsParallelism;
572	>	final boolean locallyFifo;
573
574		/**
575	<	* The uncaught exception handler used when any worker
576	<	* abruptly terminates
575	>	* The uncaught exception handler used when any worker abruptly
576	>	* terminates.
577		*/
578	<	private Thread.UncaughtExceptionHandler ueh;
578	>	private final Thread.UncaughtExceptionHandler ueh;
579
580		/**
581		* Pool number, just for assigning useful names to worker threads
582		*/
583		private final int poolNumber;
584
585	<	// utilities for updating fields
585	>	// Utilities for CASing fields. Note that most of these
586	>	// are usually manually inlined by callers
587
588		/**
589	<	* Adds delta to running count. Used mainly by ForkJoinTask.
529	<	*
530	<	* @param delta the number to add
589	>	* Increments running count part of workerCounts
590		*/
591	<	final void updateRunningCount(int delta) {
592	<	int wc;
591	>	final void incrementRunningCount() {
592	>	int c;
593		do {} while (!UNSAFE.compareAndSwapInt(this, workerCountsOffset,
594	<	wc = workerCounts,
595	<	wc + delta));
594	>	c = workerCounts,
595	>	c + ONE_RUNNING));
596		}
597
598		/**
599	<	* Write fence for user modifications of pool parameters
541	<	* (parallelism. etc). Note that it doesn't matter if CAS fails.
599	>	* Tries to increment running count part of workerCounts
600		*/
601	<	private void workerCountWriteFence() {
602	<	int wc;
603	<	UNSAFE.compareAndSwapInt(this, workerCountsOffset,
604	<	wc = workerCounts, wc);
601	>	final boolean tryIncrementRunningCount() {
602	>	int c;
603	>	return UNSAFE.compareAndSwapInt(this, workerCountsOffset,
604	>	c = workerCounts,
605	>	c + ONE_RUNNING);
606		}
607
608		/**
609	<	* Read fence for external reads of pool parameters
551	<	* (parallelism. maxPoolSize, etc).
609	>	* Tries to decrement running count unless already zero
610		*/
611	<	private void workerCountReadFence() {
612	<	int ignore = workerCounts;
611	>	final boolean tryDecrementRunningCount() {
612	>	int wc = workerCounts;
613	>	if ((wc & RUNNING_COUNT_MASK) == 0)
614	>	return false;
615	>	return UNSAFE.compareAndSwapInt(this, workerCountsOffset,
616	>	wc, wc - ONE_RUNNING);
617		}
618
619		/**
620	<	* Tries incrementing active count; fails on contention.
621	<	* Called by workers before executing tasks.
620	>	* Forces decrement of encoded workerCounts, awaiting nonzero if
621	>	* (rarely) necessary when other count updates lag.
622		*
623	<	* @return true on success
623	>	* @param dr -- either zero or ONE_RUNNING
624	>	* @param dt -- either zero or ONE_TOTAL
625		*/
626	<	final boolean tryIncrementActiveCount() {
627	<	int c;
628	<	return UNSAFE.compareAndSwapInt(this, runStateOffset,
629	<	c = runState, c + ONE_ACTIVE);
626	>	private void decrementWorkerCounts(int dr, int dt) {
627	>	for (;;) {
628	>	int wc = workerCounts;
629	>	if ((wc & RUNNING_COUNT_MASK) - dr < 0 \|\|
630	>	(wc >>> TOTAL_COUNT_SHIFT) - dt < 0) {
631	>	if ((runState & TERMINATED) != 0)
632	>	return; // lagging termination on a backout
633	>	Thread.yield();
634	>	}
635	>	if (UNSAFE.compareAndSwapInt(this, workerCountsOffset,
636	>	wc, wc - (dr + dt)))
637	>	return;
638	>	}
639		}
640
641		/**
#	Line 573 \| Line 645 \| public class ForkJoinPool extends Abstra
645		final boolean tryDecrementActiveCount() {
646		int c;
647		return UNSAFE.compareAndSwapInt(this, runStateOffset,
648	<	c = runState, c - ONE_ACTIVE);
648	>	c = runState, c - 1);
649		}
650
651		/**
#	Line 602 \| Line 674 \| public class ForkJoinPool extends Abstra
674		lock.lock();
675		try {
676		ForkJoinWorkerThread[] ws = workers;
677	<	int len = ws.length;
678	<	if (k < 0 \|\| k >= len \|\| ws[k] != null) {
679	<	for (k = 0; k < len && ws[k] != null; ++k)
677	>	int n = ws.length;
678	>	if (k < 0 \|\| k >= n \|\| ws[k] != null) {
679	>	for (k = 0; k < n && ws[k] != null; ++k)
680		;
681	<	if (k == len)
682	<	ws = Arrays.copyOf(ws, len << 1);
681	>	if (k == n)
682	>	ws = workers = Arrays.copyOf(ws, n << 1);
683		}
684		ws[k] = w;
685	<	workers = ws; // volatile array write ensures slot visibility
685	>	int c = eventCount; // advance event count to ensure visibility
686	>	UNSAFE.compareAndSwapInt(this, eventCountOffset, c, c+1);
687		} finally {
688		lock.unlock();
689		}
#	Line 618 \| Line 691 \| public class ForkJoinPool extends Abstra
691		}
692
693		/**
694	<	* Nulls out record of worker in workers array
694	>	* Nulls out record of worker in workers array.
695		*/
696		private void forgetWorker(ForkJoinWorkerThread w) {
697		int idx = w.poolIndex;
698	<	// Locking helps method recordWorker avoid unecessary expansion
698	>	// Locking helps method recordWorker avoid unnecessary expansion
699		final ReentrantLock lock = this.workerLock;
700		lock.lock();
701		try {
#	Line 634 \| Line 707 \| public class ForkJoinPool extends Abstra
707		}
708		}
709
637	–	// adding and removing workers
638	–
710		/**
711	<	* Tries to create and add new worker. Assumes that worker counts
712	<	* are already updated to accommodate the worker, so adjusts on
713	<	* failure.
711	>	* Final callback from terminating worker. Removes record of
712	>	* worker from array, and adjusts counts. If pool is shutting
713	>	* down, tries to complete termination.
714		*
715	<	* @return new worker or null if creation failed
715	>	* @param w the worker
716		*/
717	<	private ForkJoinWorkerThread addWorker() {
718	<	ForkJoinWorkerThread w = null;
719	<	try {
720	<	w = factory.newThread(this);
721	<	} finally { // Adjust on either null or exceptional factory return
722	<	if (w == null) {
723	<	onWorkerCreationFailure();
724	<	return null;
717	>	final void workerTerminated(ForkJoinWorkerThread w) {
718	>	forgetWorker(w);
719	>	decrementWorkerCounts(w.isTrimmed() ? 0 : ONE_RUNNING, ONE_TOTAL);
720	>	while (w.stealCount != 0) // collect final count
721	>	tryAccumulateStealCount(w);
722	>	tryTerminate(false);
723	>	}
724	>
725	>	// Waiting for and signalling events
726	>
727	>	/**
728	>	* Releases workers blocked on a count not equal to current count.
729	>	* Normally called after precheck that eventWaiters isn't zero to
730	>	* avoid wasted array checks. Gives up upon a change in count or
731	>	* upon releasing two workers, letting others take over.
732	>	*/
733	>	private void releaseEventWaiters() {
734	>	ForkJoinWorkerThread[] ws = workers;
735	>	int n = ws.length;
736	>	long h = eventWaiters;
737	>	int ec = eventCount;
738	>	boolean releasedOne = false;
739	>	ForkJoinWorkerThread w; int id;
740	>	while ((id = ((int)(h & WAITER_ID_MASK)) - 1) >= 0 &&
741	>	(int)(h >>> EVENT_COUNT_SHIFT) != ec &&
742	>	id < n && (w = ws[id]) != null) {
743	>	if (UNSAFE.compareAndSwapLong(this, eventWaitersOffset,
744	>	h, w.nextWaiter)) {
745	>	LockSupport.unpark(w);
746	>	if (releasedOne) // exit on second release
747	>	break;
748	>	releasedOne = true;
749		}
750	+	if (eventCount != ec)
751	+	break;
752	+	h = eventWaiters;
753		}
656	–	w.start(recordWorker(w), locallyFifo, ueh);
657	–	return w;
754		}
755
756		/**
757	<	* Adjusts counts upon failure to create worker
757	>	* Tries to advance eventCount and releases waiters. Called only
758	>	* from workers.
759		*/
760	<	private void onWorkerCreationFailure() {
761	<	int c;
762	<	do {} while (!UNSAFE.compareAndSwapInt(this, workerCountsOffset,
763	<	c = workerCounts,
764	<	c - (ONE_RUNNING\|ONE_TOTAL)));
668	<	tryTerminate(false); // in case of failure during shutdown
760	>	final void signalWork() {
761	>	int c; // try to increment event count -- CAS failure OK
762	>	UNSAFE.compareAndSwapInt(this, eventCountOffset, c = eventCount, c+1);
763	>	if (eventWaiters != 0L)
764	>	releaseEventWaiters();
765		}
766
767		/**
768	<	* Create enough total workers to establish target parallelism,
769	<	* giving up if terminating or addWorker fails
768	>	* Adds the given worker to event queue and blocks until
769	>	* terminating or event count advances from the given value
770	>	*
771	>	* @param w the calling worker thread
772	>	* @param ec the count
773		*/
774	<	private void ensureEnoughTotalWorkers() {
775	<	int wc;
776	<	while (runState < TERMINATING &&
777	<	((wc = workerCounts) >>> TOTAL_COUNT_SHIFT) < parallelism) {
778	<	if ((UNSAFE.compareAndSwapInt(this, workerCountsOffset,
779	<	wc, wc + (ONE_RUNNING\|ONE_TOTAL)) &&
780	<	addWorker() == null))
774	>	private void eventSync(ForkJoinWorkerThread w, int ec) {
775	>	long nh = (((long)ec) << EVENT_COUNT_SHIFT) \| ((long)(w.poolIndex+1));
776	>	long h;
777	>	while ((runState < SHUTDOWN \|\| !tryTerminate(false)) &&
778	>	(((int)((h = eventWaiters) & WAITER_ID_MASK)) == 0 \|\|
779	>	(int)(h >>> EVENT_COUNT_SHIFT) == ec) &&
780	>	eventCount == ec) {
781	>	if (UNSAFE.compareAndSwapLong(this, eventWaitersOffset,
782	>	w.nextWaiter = h, nh)) {
783	>	awaitEvent(w, ec);
784		break;
785	+	}
786		}
787		}
788
789		/**
790	<	* Final callback from terminating worker. Removes record of
791	<	* worker from array, and adjusts counts. If pool is shutting
792	<	* down, tries to complete terminatation, else possibly replaces
793	<	* the worker.
790	>	* Blocks the given worker (that has already been entered as an
791	>	* event waiter) until terminating or event count advances from
792	>	* the given value. The oldest (first) waiter uses a timed wait to
793	>	* occasionally one-by-one shrink the number of workers (to a
794	>	* minimum of one) if the pool has not been used for extended
795	>	* periods.
796		*
797	<	* @param w the worker
797	>	* @param w the calling worker thread
798	>	* @param ec the count
799		*/
800	<	final void workerTerminated(ForkJoinWorkerThread w) {
801	<	if (w.active) { // force inactive
802	<	w.active = false;
803	<	do {} while (!tryDecrementActiveCount());
800	>	private void awaitEvent(ForkJoinWorkerThread w, int ec) {
801	>	while (eventCount == ec) {
802	>	if (tryAccumulateStealCount(w)) { // transfer while idle
803	>	boolean untimed = (w.nextWaiter != 0L \|\|
804	>	(workerCounts & RUNNING_COUNT_MASK) <= 1);
805	>	long startTime = untimed ? 0 : System.nanoTime();
806	>	Thread.interrupted(); // clear/ignore interrupt
807	>	if (w.isTerminating() \|\| eventCount != ec)
808	>	break; // recheck after clear
809	>	if (untimed)
810	>	LockSupport.park(w);
811	>	else {
812	>	LockSupport.parkNanos(w, SHRINK_RATE_NANOS);
813	>	if (eventCount != ec \|\| w.isTerminating())
814	>	break;
815	>	if (System.nanoTime() - startTime >= SHRINK_RATE_NANOS)
816	>	tryShutdownUnusedWorker(ec);
817	>	}
818	>	}
819		}
699	–	forgetWorker(w);
700	–
701	–	// decrement total count, and if was running, running count
702	–	int unit = w.isTrimmed()? ONE_TOTAL : (ONE_RUNNING\|ONE_TOTAL);
703	–	int wc;
704	–	do {} while (!UNSAFE.compareAndSwapInt(this, workerCountsOffset,
705	–	wc = workerCounts, wc - unit));
706	–
707	–	accumulateStealCount(w); // collect final count
708	–	if (!tryTerminate(false))
709	–	ensureEnoughTotalWorkers();
820		}
821
822	<	// Waiting for and signalling events
822	>	// Maintaining parallelism
823
824		/**
825	<	* Ensures eventCount on exit is different (mod 2^32) than on
716	<	* entry. CAS failures are OK -- any change in count suffices.
825	>	* Pushes worker onto the spare stack.
826		*/
827	<	private void advanceEventCount() {
828	<	int c;
829	<	UNSAFE.compareAndSwapInt(this, eventCountOffset, c = eventCount, c+1);
827	>	final void pushSpare(ForkJoinWorkerThread w) {
828	>	int ns = (++w.spareCount << SPARE_COUNT_SHIFT) \| (w.poolIndex + 1);
829	>	do {} while (!UNSAFE.compareAndSwapInt(this, spareWaitersOffset,
830	>	w.nextSpare = spareWaiters,ns));
831		}
832
833		/**
834	<	* Releases workers blocked on a count not equal to current count.
835	<	*/
836	<	final void releaseWaiters() {
837	<	long top;
838	<	int id;
839	<	while ((id = (int)((top = eventWaiters) & WAITER_INDEX_MASK)) > 0 &&
840	<	(int)(top >>> EVENT_COUNT_SHIFT) != eventCount) {
841	<	ForkJoinWorkerThread[] ws = workers;
842	<	ForkJoinWorkerThread w;
843	<	if (ws.length >= id && (w = ws[id - 1]) != null &&
844	<	UNSAFE.compareAndSwapLong(this, eventWaitersOffset,
845	<	top, w.nextWaiter))
834	>	* Tries (once) to resume a spare if the number of running
835	>	* threads is less than target.
836	>	*/
837	>	private void tryResumeSpare() {
838	>	int sw, id;
839	>	ForkJoinWorkerThread[] ws = workers;
840	>	int n = ws.length;
841	>	ForkJoinWorkerThread w;
842	>	if ((sw = spareWaiters) != 0 &&
843	>	(id = (sw & SPARE_ID_MASK) - 1) >= 0 &&
844	>	id < n && (w = ws[id]) != null &&
845	>	(runState >= TERMINATING \|\|
846	>	(workerCounts & RUNNING_COUNT_MASK) < parallelism) &&
847	>	spareWaiters == sw &&
848	>	UNSAFE.compareAndSwapInt(this, spareWaitersOffset,
849	>	sw, w.nextSpare)) {
850	>	int c; // increment running count before resume
851	>	do {} while (!UNSAFE.compareAndSwapInt
852	>	(this, workerCountsOffset,
853	>	c = workerCounts, c + ONE_RUNNING));
854	>	if (w.tryUnsuspend())
855		LockSupport.unpark(w);
856	+	else // back out if w was shutdown
857	+	decrementWorkerCounts(ONE_RUNNING, 0);
858		}
859		}
860
861		/**
862	<	* Advances eventCount and releases waiters until interference by
863	<	* other releasing threads is detected.
862	>	* Tries to increase the number of running workers if below target
863	>	* parallelism: If a spare exists tries to resume it via
864	>	* tryResumeSpare. Otherwise, if not enough total workers or all
865	>	* existing workers are busy, adds a new worker. In all cases also
866	>	* helps wake up releasable workers waiting for work.
867		*/
868	<	final void signalWork() {
869	<	int ec;
870	<	UNSAFE.compareAndSwapInt(this, eventCountOffset, ec=eventCount, ec+1);
871	<	outer:for (;;) {
872	<	long top = eventWaiters;
873	<	ec = eventCount;
874	<	for (;;) {
875	<	ForkJoinWorkerThread[] ws; ForkJoinWorkerThread w;
876	<	int id = (int)(top & WAITER_INDEX_MASK);
877	<	if (id <= 0 \|\| (int)(top >>> EVENT_COUNT_SHIFT) == ec)
878	<	return;
879	<	if ((ws = workers).length < id \|\| (w = ws[id - 1]) == null \|\|
880	<	!UNSAFE.compareAndSwapLong(this, eventWaitersOffset,
881	<	top, top = w.nextWaiter))
882	<	continue outer; // possibly stale; reread
883	<	LockSupport.unpark(w);
884	<	if (top != eventWaiters) // let someone else take over
885	<	return;
868	>	private void helpMaintainParallelism() {
869	>	int pc = parallelism;
870	>	int wc, rs, tc;
871	>	while (((wc = workerCounts) & RUNNING_COUNT_MASK) < pc &&
872	>	(rs = runState) < TERMINATING) {
873	>	if (spareWaiters != 0)
874	>	tryResumeSpare();
875	>	else if ((tc = wc >>> TOTAL_COUNT_SHIFT) >= MAX_WORKERS \|\|
876	>	(tc >= pc && (rs & ACTIVE_COUNT_MASK) != tc))
877	>	break; // enough total
878	>	else if (runState == rs && workerCounts == wc &&
879	>	UNSAFE.compareAndSwapInt(this, workerCountsOffset, wc,
880	>	wc + (ONE_RUNNING\|ONE_TOTAL))) {
881	>	ForkJoinWorkerThread w = null;
882	>	Throwable fail = null;
883	>	try {
884	>	w = factory.newThread(this);
885	>	} catch (Throwable ex) {
886	>	fail = ex;
887	>	}
888	>	if (w == null) { // null or exceptional factory return
889	>	decrementWorkerCounts(ONE_RUNNING, ONE_TOTAL);
890	>	tryTerminate(false); // handle failure during shutdown
891	>	// If originating from an external caller,
892	>	// propagate exception, else ignore
893	>	if (fail != null && runState < TERMINATING &&
894	>	!(Thread.currentThread() instanceof
895	>	ForkJoinWorkerThread))
896	>	UNSAFE.throwException(fail);
897	>	break;
898	>	}
899	>	w.start(recordWorker(w), ueh);
900	>	if ((workerCounts >>> TOTAL_COUNT_SHIFT) >= pc)
901	>	break; // add at most one unless total below target
902		}
903		}
904	+	if (eventWaiters != 0L)
905	+	releaseEventWaiters();
906		}
907
908		/**
909	<	* If worker is inactive, blocks until terminating or event count
910	<	* advances from last value held by worker; in any case helps
911	<	* release others.
909	>	* Callback from the oldest waiter in awaitEvent waking up after a
910	>	* period of non-use. If all workers are idle, tries (once) to
911	>	* shutdown an event waiter or a spare, if one exists. Note that
912	>	* we don't need CAS or locks here because the method is called
913	>	* only from one thread occasionally waking (and even misfires are
914	>	* OK). Note that until the shutdown worker fully terminates,
915	>	* workerCounts will overestimate total count, which is tolerable.
916		*
917	<	* @param w the calling worker thread
917	>	* @param ec the event count waited on by caller (to abort
918	>	* attempt if count has since changed).
919		*/
920	<	private void eventSync(ForkJoinWorkerThread w) {
921	<	if (!w.active) {
922	<	int prev = w.lastEventCount;
923	<	long nextTop = (((long)prev << EVENT_COUNT_SHIFT) \|
924	<	((long)(w.poolIndex + 1)));
925	<	long top;
926	<	while ((runState < SHUTDOWN \|\| !tryTerminate(false)) &&
927	<	(((int)(top = eventWaiters) & WAITER_INDEX_MASK) == 0 \|\|
928	<	(int)(top >>> EVENT_COUNT_SHIFT) == prev) &&
929	<	eventCount == prev) {
930	<	if (UNSAFE.compareAndSwapLong(this, eventWaitersOffset,
931	<	w.nextWaiter = top, nextTop)) {
932	<	accumulateStealCount(w); // transfer steals while idle
933	<	Thread.interrupted(); // clear/ignore interrupt
934	<	while (eventCount == prev)
935	<	w.doPark();
936	<	break;
937	<	}
920	>	private void tryShutdownUnusedWorker(int ec) {
921	>	if (runState == 0 && eventCount == ec) { // only trigger if all idle
922	>	ForkJoinWorkerThread[] ws = workers;
923	>	int n = ws.length;
924	>	ForkJoinWorkerThread w = null;
925	>	boolean shutdown = false;
926	>	int sw;
927	>	long h;
928	>	if ((sw = spareWaiters) != 0) { // prefer killing spares
929	>	int id = (sw & SPARE_ID_MASK) - 1;
930	>	if (id >= 0 && id < n && (w = ws[id]) != null &&
931	>	UNSAFE.compareAndSwapInt(this, spareWaitersOffset,
932	>	sw, w.nextSpare))
933	>	shutdown = true;
934	>	}
935	>	else if ((h = eventWaiters) != 0L) {
936	>	long nh;
937	>	int id = ((int)(h & WAITER_ID_MASK)) - 1;
938	>	if (id >= 0 && id < n && (w = ws[id]) != null &&
939	>	(nh = w.nextWaiter) != 0L && // keep at least one worker
940	>	UNSAFE.compareAndSwapLong(this, eventWaitersOffset, h, nh))
941	>	shutdown = true;
942	>	}
943	>	if (w != null && shutdown) {
944	>	w.shutdown();
945	>	LockSupport.unpark(w);
946		}
792	–	w.lastEventCount = eventCount;
947		}
948	<	releaseWaiters();
948	>	releaseEventWaiters(); // in case of interference
949		}
950
951		/**
952		* Callback from workers invoked upon each top-level action (i.e.,
953	<	* stealing a task or taking a submission and running
954	<	* it). Performs one or both of the following:
953	>	* stealing a task or taking a submission and running it).
954	>	* Performs one or more of the following:
955		*
956	<	* * If the worker cannot find work, updates its active status to
957	<	* inactive and updates activeCount unless there is contention, in
958	<	* which case it may try again (either in this or a subsequent
959	<	* call). Additionally, awaits the next task event and/or helps
960	<	* wake up other releasable waiters.
961	<	*
962	<	* * If there are too many running threads, suspends this worker
963	<	* (first forcing inactivation if necessary). If it is not
964	<	* resumed before a keepAlive elapses, the worker may be "trimmed"
965	<	* -- killed while suspended within suspendAsSpare. Otherwise,
966	<	* upon resume it rechecks to make sure that it is still needed.
956	>	* 1. If the worker is active and either did not run a task
957	>	* or there are too many workers, try to set its active status
958	>	* to inactive and update activeCount. On contention, we may
959	>	* try again in this or a subsequent call.
960	>	*
961	>	* 2. If not enough total workers, help create some.
962	>	*
963	>	* 3. If there are too many running workers, suspend this worker
964	>	* (first forcing inactive if necessary). If it is not needed,
965	>	* it may be shutdown while suspended (via
966	>	* tryShutdownUnusedWorker). Otherwise, upon resume it
967	>	* rechecks running thread count and need for event sync.
968	>	*
969	>	* 4. If worker did not run a task, await the next task event via
970	>	* eventSync if necessary (first forcing inactivation), upon
971	>	* which the worker may be shutdown via
972	>	* tryShutdownUnusedWorker. Otherwise, help release any
973	>	* existing event waiters that are now releasable,
974		*
975		* @param w the worker
976	<	* @param worked false if the worker scanned for work but didn't
816	<	* find any (in which case it may block waiting for work).
976	>	* @param ran true if worker ran a task since last call to this method
977		*/
978	<	final void preStep(ForkJoinWorkerThread w, boolean worked) {
978	>	final void preStep(ForkJoinWorkerThread w, boolean ran) {
979	>	int wec = w.lastEventCount;
980		boolean active = w.active;
981	<	boolean inactivate = !worked & active;
982	<	for (;;) {
983	<	if (inactivate) {
984	<	int c = runState;
985	<	if (UNSAFE.compareAndSwapInt(this, runStateOffset,
986	<	c, c - ONE_ACTIVE))
987	<	inactivate = active = w.active = false;
827	<	}
828	<	int wc = workerCounts;
829	<	if ((wc & RUNNING_COUNT_MASK) <= parallelism) {
830	<	if (!worked)
831	<	eventSync(w);
832	<	return;
981	>	boolean inactivate = false;
982	>	int pc = parallelism;
983	>	while (w.runState == 0) {
984	>	int rs = runState;
985	>	if (rs >= TERMINATING) { // propagate shutdown
986	>	w.shutdown();
987	>	break;
988		}
989	<	if (!(inactivate \|= active) && // must inactivate to suspend
990	<	UNSAFE.compareAndSwapInt(this, workerCountsOffset,
991	<	wc, wc - ONE_RUNNING) &&
992	<	!w.suspendAsSpare()) // false if trimmed
993	<	return;
994	<	}
840	<	}
841	<
842	<	/**
843	<	* Adjusts counts and creates or resumes compensating threads for
844	<	* a worker about to block on task joinMe, returning early if
845	<	* joinMe becomes ready. First tries resuming an existing spare
846	<	* (which usually also avoids any count adjustment), but must then
847	<	* decrement running count to determine whether a new thread is
848	<	* needed. See above for fuller explanation.
849	<	*/
850	<	final void preJoin(ForkJoinTask<?> joinMe) {
851	<	boolean dec = false; // true when running count decremented
852	<	for (;;) {
853	<	releaseWaiters(); // help other threads progress
854	<
855	<	if (joinMe.status < 0) // surround spare search with done checks
856	<	return;
857	<	ForkJoinWorkerThread spare = null;
858	<	for (ForkJoinWorkerThread w : workers) {
859	<	if (w != null && w.isSuspended()) {
860	<	spare = w;
861	<	break;
989	>	if ((inactivate \|\| (active && (rs & ACTIVE_COUNT_MASK) >= pc)) &&
990	>	UNSAFE.compareAndSwapInt(this, runStateOffset, rs, --rs)) {
991	>	inactivate = active = w.active = false;
992	>	if (rs == SHUTDOWN) { // all inactive and shut down
993	>	tryTerminate(false);
994	>	continue;
995		}
996		}
997	<	if (joinMe.status < 0)
998	<	return;
999	<
1000	<	if (spare != null && spare.tryUnsuspend()) {
1001	<	if (dec \|\| joinMe.requestSignal() < 0) {
1002	<	int c;
1003	<	do {} while (!UNSAFE.compareAndSwapInt(this,
871	<	workerCountsOffset,
872	<	c = workerCounts,
873	<	c + ONE_RUNNING));
874	<	} // else no net count change
875	<	LockSupport.unpark(spare);
876	<	return;
877	<	}
878	<
879	<	int wc = workerCounts; // decrement running count
880	<	if (!dec && (wc & RUNNING_COUNT_MASK) != 0 &&
881	<	(dec = UNSAFE.compareAndSwapInt(this, workerCountsOffset,
882	<	wc, wc -= ONE_RUNNING)) &&
883	<	joinMe.requestSignal() < 0) { // cannot block
884	<	int c; // back out
885	<	do {} while (!UNSAFE.compareAndSwapInt(this,
886	<	workerCountsOffset,
887	<	c = workerCounts,
888	<	c + ONE_RUNNING));
889	<	return;
997	>	int wc = workerCounts; // try to suspend as spare
998	>	if ((wc & RUNNING_COUNT_MASK) > pc) {
999	>	if (!(inactivate \|= active) && // must inactivate to suspend
1000	>	workerCounts == wc &&
1001	>	UNSAFE.compareAndSwapInt(this, workerCountsOffset,
1002	>	wc, wc - ONE_RUNNING))
1003	>	w.suspendAsSpare();
1004		}
1005	<
1006	<	if (dec) {
1007	<	int tc = wc >>> TOTAL_COUNT_SHIFT;
1008	<	int pc = parallelism;
1009	<	int dc = pc - (wc & RUNNING_COUNT_MASK); // deficit count
1010	<	if ((dc < pc && (dc <= 0 \|\| (dc * dc < (tc - pc) * pc) \|\|
1011	<	!maintainsParallelism)) \|\|
1012	<	tc >= maxPoolSize) // cannot add
1013	<	return;
1014	<	if (spare == null &&
1015	<	UNSAFE.compareAndSwapInt(this, workerCountsOffset, wc,
1016	<	wc + (ONE_RUNNING\|ONE_TOTAL))) {
903	<	addWorker();
904	<	return;
1005	>	else if ((wc >>> TOTAL_COUNT_SHIFT) < pc)
1006	>	helpMaintainParallelism(); // not enough workers
1007	>	else if (ran)
1008	>	break;
1009	>	else {
1010	>	long h = eventWaiters;
1011	>	int ec = eventCount;
1012	>	if (h != 0L && (int)(h >>> EVENT_COUNT_SHIFT) != ec)
1013	>	releaseEventWaiters(); // release others before waiting
1014	>	else if (ec != wec) {
1015	>	w.lastEventCount = ec; // no need to wait
1016	>	break;
1017		}
1018	+	else if (!(inactivate \|= active))
1019	+	eventSync(w, wec); // must inactivate before sync
1020		}
1021		}
1022		}
1023
1024		/**
1025	<	* Same idea as preJoin but with too many differing details to
1026	<	* integrate: There are no task-based signal counts, and only one
1027	<	* way to do the actual blocking. So for simplicity it is directly
1028	<	* incorporated into this method.
1029	<	*/
1030	<	final void doBlock(ManagedBlocker blocker, boolean maintainPar)
1031	<	throws InterruptedException {
1032	<	maintainPar &= maintainsParallelism; // override
1033	<	boolean dec = false;
1034	<	boolean done = false;
1035	<	for (;;) {
1036	<	releaseWaiters();
1037	<	if (done = blocker.isReleasable())
1025	>	* Helps and/or blocks awaiting join of the given task.
1026	>	* See above for explanation.
1027	>	*
1028	>	* @param joinMe the task to join
1029	>	* @param worker the current worker thread
1030	>	* @param timed true if wait should time out
1031	>	* @param nanos timeout value if timed
1032	>	*/
1033	>	final void awaitJoin(ForkJoinTask<?> joinMe, ForkJoinWorkerThread worker,
1034	>	boolean timed, long nanos) {
1035	>	long startTime = timed? System.nanoTime() : 0L;
1036	>	int retries = 2 + (parallelism >> 2); // #helpJoins before blocking
1037	>	boolean running = true; // false when count decremented
1038	>	while (joinMe.status >= 0) {
1039	>	if (runState >= TERMINATING) {
1040	>	joinMe.cancelIgnoringExceptions();
1041		break;
925	–	ForkJoinWorkerThread spare = null;
926	–	for (ForkJoinWorkerThread w : workers) {
927	–	if (w != null && w.isSuspended()) {
928	–	spare = w;
929	–	break;
930	–	}
1042		}
1043	<	if (done = blocker.isReleasable())
1044	<	break;
934	<	if (spare != null && spare.tryUnsuspend()) {
935	<	if (dec) {
936	<	int c;
937	<	do {} while (!UNSAFE.compareAndSwapInt(this,
938	<	workerCountsOffset,
939	<	c = workerCounts,
940	<	c + ONE_RUNNING));
941	<	}
942	<	LockSupport.unpark(spare);
1043	>	running = worker.helpJoinTask(joinMe, running);
1044	>	if (joinMe.status < 0)
1045		break;
1046	+	if (retries > 0) {
1047	+	--retries;
1048	+	continue;
1049		}
1050		int wc = workerCounts;
1051	<	if (!dec && (wc & RUNNING_COUNT_MASK) != 0)
1052	<	dec = UNSAFE.compareAndSwapInt(this, workerCountsOffset,
1053	<	wc, wc -= ONE_RUNNING);
1054	<	if (dec) {
1055	<	int tc = wc >>> TOTAL_COUNT_SHIFT;
1056	<	int pc = parallelism;
1057	<	int dc = pc - (wc & RUNNING_COUNT_MASK);
1058	<	if ((dc < pc && (dc <= 0 \|\| (dc * dc < (tc - pc) * pc) \|\|
1059	<	!maintainPar)) \|\|
1060	<	tc >= maxPoolSize)
1061	<	break;
957	<	if (spare == null &&
958	<	UNSAFE.compareAndSwapInt(this, workerCountsOffset, wc,
959	<	wc + (ONE_RUNNING\|ONE_TOTAL))){
960	<	addWorker();
1051	>	if ((wc & RUNNING_COUNT_MASK) != 0) {
1052	>	if (running) {
1053	>	if (!UNSAFE.compareAndSwapInt(this, workerCountsOffset,
1054	>	wc, wc - ONE_RUNNING))
1055	>	continue;
1056	>	running = false;
1057	>	}
1058	>	long h = eventWaiters;
1059	>	if (h != 0L && (int)(h >>> EVENT_COUNT_SHIFT) != eventCount)
1060	>	releaseEventWaiters();
1061	>	if (joinMe.status < 0)
1062		break;
1063	+	if ((workerCounts & RUNNING_COUNT_MASK) != 0) {
1064	+	long ms; int ns;
1065	+	if (!timed) {
1066	+	ms = JOIN_TIMEOUT_MILLIS;
1067	+	ns = 0;
1068	+	}
1069	+	else { // at most JOIN_TIMEOUT_MILLIS per wait
1070	+	long nt = nanos - (System.nanoTime() - startTime);
1071	+	if (nt <= 0L)
1072	+	break;
1073	+	ms = nt / 1000000;
1074	+	if (ms > JOIN_TIMEOUT_MILLIS) {
1075	+	ms = JOIN_TIMEOUT_MILLIS;
1076	+	ns = 0;
1077	+	}
1078	+	else
1079	+	ns = (int) (nt % 1000000);
1080	+	}
1081	+	if (joinMe.internalAwaitDone(ms, ns) < 0)
1082	+	break;
1083		}
1084		}
1085	+	helpMaintainParallelism();
1086		}
1087	+	if (!running) {
1088	+	int c;
1089	+	do {} while (!UNSAFE.compareAndSwapInt
1090	+	(this, workerCountsOffset,
1091	+	c = workerCounts, c + ONE_RUNNING));
1092	+	}
1093	+	}
1094
1095	<	try {
1096	<	if (!done)
1097	<	do {} while (!blocker.isReleasable() && !blocker.block());
1098	<	} finally {
1099	<	if (dec) {
1100	<	int c;
1101	<	do {} while (!UNSAFE.compareAndSwapInt(this,
1102	<	workerCountsOffset,
1103	<	c = workerCounts,
1104	<	c + ONE_RUNNING));
1095	>	/**
1096	>	* Same idea as awaitJoin, but no helping, retries, or timeouts.
1097	>	*/
1098	>	final void awaitBlocker(ManagedBlocker blocker)
1099	>	throws InterruptedException {
1100	>	while (!blocker.isReleasable()) {
1101	>	int wc = workerCounts;
1102	>	if ((wc & RUNNING_COUNT_MASK) == 0)
1103	>	helpMaintainParallelism();
1104	>	else if (UNSAFE.compareAndSwapInt(this, workerCountsOffset,
1105	>	wc, wc - ONE_RUNNING)) {
1106	>	try {
1107	>	while (!blocker.isReleasable()) {
1108	>	long h = eventWaiters;
1109	>	if (h != 0L &&
1110	>	(int)(h >>> EVENT_COUNT_SHIFT) != eventCount)
1111	>	releaseEventWaiters();
1112	>	else if ((workerCounts & RUNNING_COUNT_MASK) == 0 &&
1113	>	runState < TERMINATING)
1114	>	helpMaintainParallelism();
1115	>	else if (blocker.block())
1116	>	break;
1117	>	}
1118	>	} finally {
1119	>	int c;
1120	>	do {} while (!UNSAFE.compareAndSwapInt
1121	>	(this, workerCountsOffset,
1122	>	c = workerCounts, c + ONE_RUNNING));
1123	>	}
1124	>	break;
1125		}
1126		}
1127		}
#	Line 998 \| Line 1147 \| public class ForkJoinPool extends Abstra
1147		// Finish now if all threads terminated; else in some subsequent call
1148		if ((workerCounts >>> TOTAL_COUNT_SHIFT) == 0) {
1149		advanceRunLevel(TERMINATED);
1150	<	terminationLatch.countDown();
1150	>	termination.forceTermination();
1151		}
1152		return true;
1153		}
1154
1155		/**
1156		* Actions on transition to TERMINATING
1157	+	*
1158	+	* Runs up to four passes through workers: (0) shutting down each
1159	+	* (without waking up if parked) to quickly spread notifications
1160	+	* without unnecessary bouncing around event queues etc (1) wake
1161	+	* up and help cancel tasks (2) interrupt (3) mop up races with
1162	+	* interrupted workers
1163		*/
1164		private void startTerminating() {
1165	<	// Clear out and cancel submissions, ignoring exceptions
1165	>	cancelSubmissions();
1166	>	for (int passes = 0; passes < 4 && workerCounts != 0; ++passes) {
1167	>	int c; // advance event count
1168	>	UNSAFE.compareAndSwapInt(this, eventCountOffset,
1169	>	c = eventCount, c+1);
1170	>	eventWaiters = 0L; // clobber lists
1171	>	spareWaiters = 0;
1172	>	for (ForkJoinWorkerThread w : workers) {
1173	>	if (w != null) {
1174	>	w.shutdown();
1175	>	if (passes > 0 && !w.isTerminated()) {
1176	>	w.cancelTasks();
1177	>	LockSupport.unpark(w);
1178	>	if (passes > 1 && !w.isInterrupted()) {
1179	>	try {
1180	>	w.interrupt();
1181	>	} catch (SecurityException ignore) {
1182	>	}
1183	>	}
1184	>	}
1185	>	}
1186	>	}
1187	>	}
1188	>	}
1189	>
1190	>	/**
1191	>	* Clears out and cancels submissions, ignoring exceptions.
1192	>	*/
1193	>	private void cancelSubmissions() {
1194		ForkJoinTask<?> task;
1195		while ((task = submissionQueue.poll()) != null) {
1196		try {
#	Line 1015 \| Line 1198 \| public class ForkJoinPool extends Abstra
1198		} catch (Throwable ignore) {
1199		}
1200		}
1018	–	// Propagate run level
1019	–	for (ForkJoinWorkerThread w : workers) {
1020	–	if (w != null)
1021	–	w.shutdown(); // also resumes suspended workers
1022	–	}
1023	–	// Ensure no straggling local tasks
1024	–	for (ForkJoinWorkerThread w : workers) {
1025	–	if (w != null)
1026	–	w.cancelTasks();
1027	–	}
1028	–	// Wake up idle workers
1029	–	advanceEventCount();
1030	–	releaseWaiters();
1031	–	// Unstick pending joins
1032	–	for (ForkJoinWorkerThread w : workers) {
1033	–	if (w != null && !w.isTerminated()) {
1034	–	try {
1035	–	w.interrupt();
1036	–	} catch (SecurityException ignore) {
1037	–	}
1038	–	}
1039	–	}
1201		}
1202
1203		// misc support for ForkJoinWorkerThread
1204
1205		/**
1206	<	* Returns pool number
1206	>	* Returns pool number.
1207		*/
1208		final int getPoolNumber() {
1209		return poolNumber;
1210		}
1211
1212		/**
1213	<	* Accumulates steal count from a worker, clearing
1214	<	* the worker's value
1213	>	* Tries to accumulate steal count from a worker, clearing
1214	>	* the worker's value if successful.
1215	>	*
1216	>	* @return true if worker steal count now zero
1217		*/
1218	<	final void accumulateStealCount(ForkJoinWorkerThread w) {
1218	>	final boolean tryAccumulateStealCount(ForkJoinWorkerThread w) {
1219		int sc = w.stealCount;
1220	<	if (sc != 0) {
1221	<	long c;
1222	<	w.stealCount = 0;
1223	<	do {} while (!UNSAFE.compareAndSwapLong(this, stealCountOffset,
1224	<	c = stealCount, c + sc));
1220	>	long c = stealCount;
1221	>	// CAS even if zero, for fence effects
1222	>	if (UNSAFE.compareAndSwapLong(this, stealCountOffset, c, c + sc)) {
1223	>	if (sc != 0)
1224	>	w.stealCount = 0;
1225	>	return true;
1226		}
1227	+	return sc == 0;
1228		}
1229
1230		/**
#	Line 1067 \| Line 1232 \| public class ForkJoinPool extends Abstra
1232		* active thread.
1233		*/
1234		final int idlePerActive() {
1235	<	int ac = runState; // no mask -- artifically boosts during shutdown
1236	<	int pc = parallelism; // use targeted parallelism, not rc
1235	>	int pc = parallelism; // use parallelism, not rc
1236	>	int ac = runState; // no mask -- artificially boosts during shutdown
1237		// Use exact results for small values, saturate past 4
1238	<	return pc <= ac? 0 : pc >>> 1 <= ac? 1 : pc >>> 2 <= ac? 3 : pc >>> 3;
1239	<	}
1240	<
1241	<	/**
1077	<	* Returns the approximate (non-atomic) difference between running
1078	<	* and active counts.
1079	<	*/
1080	<	final int inactiveCount() {
1081	<	return (workerCounts & RUNNING_COUNT_MASK) -
1082	<	(runState & ACTIVE_COUNT_MASK);
1238	>	return ((pc <= ac) ? 0 :
1239	>	(pc >>> 1 <= ac) ? 1 :
1240	>	(pc >>> 2 <= ac) ? 3 :
1241	>	pc >>> 3);
1242		}
1243
1244		// Public and protected methods
#	Line 1088 \| Line 1247 \| public class ForkJoinPool extends Abstra
1247
1248		/**
1249		* Creates a {@code ForkJoinPool} with parallelism equal to {@link
1250	<	* java.lang.Runtime#availableProcessors}, and using the {@linkplain
1251	<	* #defaultForkJoinWorkerThreadFactory default thread factory}.
1250	>	* java.lang.Runtime#availableProcessors}, using the {@linkplain
1251	>	* #defaultForkJoinWorkerThreadFactory default thread factory},
1252	>	* no UncaughtExceptionHandler, and non-async LIFO processing mode.
1253		*
1254		* @throws SecurityException if a security manager exists and
1255		* the caller is not permitted to modify threads
#	Line 1098 \| Line 1258 \| public class ForkJoinPool extends Abstra
1258		*/
1259		public ForkJoinPool() {
1260		this(Runtime.getRuntime().availableProcessors(),
1261	<	defaultForkJoinWorkerThreadFactory);
1261	>	defaultForkJoinWorkerThreadFactory, null, false);
1262		}
1263
1264		/**
1265		* Creates a {@code ForkJoinPool} with the indicated parallelism
1266	<	* level and using the {@linkplain
1267	<	* #defaultForkJoinWorkerThreadFactory default thread factory}.
1266	>	* level, the {@linkplain
1267	>	* #defaultForkJoinWorkerThreadFactory default thread factory},
1268	>	* no UncaughtExceptionHandler, and non-async LIFO processing mode.
1269		*
1270		* @param parallelism the parallelism level
1271		* @throws IllegalArgumentException if parallelism less than or
#	Line 1115 \| Line 1276 \| public class ForkJoinPool extends Abstra
1276		* java.lang.RuntimePermission}{@code ("modifyThread")}
1277		*/
1278		public ForkJoinPool(int parallelism) {
1279	<	this(parallelism, defaultForkJoinWorkerThreadFactory);
1279	>	this(parallelism, defaultForkJoinWorkerThreadFactory, null, false);
1280		}
1281
1282		/**
1283	<	* Creates a {@code ForkJoinPool} with parallelism equal to {@link
1123	<	* java.lang.Runtime#availableProcessors}, and using the given
1124	<	* thread factory.
1283	>	* Creates a {@code ForkJoinPool} with the given parameters.
1284		*
1285	<	* @param factory the factory for creating new threads
1286	<	* @throws NullPointerException if the factory is null
1287	<	* @throws SecurityException if a security manager exists and
1288	<	* the caller is not permitted to modify threads
1289	<	* because it does not hold {@link
1290	<	* java.lang.RuntimePermission}{@code ("modifyThread")}
1291	<	*/
1292	<	public ForkJoinPool(ForkJoinWorkerThreadFactory factory) {
1293	<	this(Runtime.getRuntime().availableProcessors(), factory);
1294	<	}
1295	<
1296	<	/**
1297	<	* Creates a {@code ForkJoinPool} with the given parallelism and
1139	<	* thread factory.
1140	<	*
1141	<	* @param parallelism the parallelism level
1142	<	* @param factory the factory for creating new threads
1285	>	* @param parallelism the parallelism level. For default value,
1286	>	* use {@link java.lang.Runtime#availableProcessors}.
1287	>	* @param factory the factory for creating new threads. For default value,
1288	>	* use {@link #defaultForkJoinWorkerThreadFactory}.
1289	>	* @param handler the handler for internal worker threads that
1290	>	* terminate due to unrecoverable errors encountered while executing
1291	>	* tasks. For default value, use {@code null}.
1292	>	* @param asyncMode if true,
1293	>	* establishes local first-in-first-out scheduling mode for forked
1294	>	* tasks that are never joined. This mode may be more appropriate
1295	>	* than default locally stack-based mode in applications in which
1296	>	* worker threads only process event-style asynchronous tasks.
1297	>	* For default value, use {@code false}.
1298		* @throws IllegalArgumentException if parallelism less than or
1299		* equal to zero, or greater than implementation limit
1300		* @throws NullPointerException if the factory is null
#	Line 1148 \| Line 1303 \| public class ForkJoinPool extends Abstra
1303		* because it does not hold {@link
1304		* java.lang.RuntimePermission}{@code ("modifyThread")}
1305		*/
1306	<	public ForkJoinPool(int parallelism, ForkJoinWorkerThreadFactory factory) {
1306	>	public ForkJoinPool(int parallelism,
1307	>	ForkJoinWorkerThreadFactory factory,
1308	>	Thread.UncaughtExceptionHandler handler,
1309	>	boolean asyncMode) {
1310		checkPermission();
1311		if (factory == null)
1312		throw new NullPointerException();
1313	<	if (parallelism <= 0 \|\| parallelism > MAX_THREADS)
1313	>	if (parallelism <= 0 \|\| parallelism > MAX_WORKERS)
1314		throw new IllegalArgumentException();
1157	–	this.poolNumber = poolNumberGenerator.incrementAndGet();
1158	–	int arraySize = initialArraySizeFor(parallelism);
1315		this.parallelism = parallelism;
1316		this.factory = factory;
1317	<	this.maxPoolSize = MAX_THREADS;
1318	<	this.maintainsParallelism = true;
1317	>	this.ueh = handler;
1318	>	this.locallyFifo = asyncMode;
1319	>	int arraySize = initialArraySizeFor(parallelism);
1320		this.workers = new ForkJoinWorkerThread[arraySize];
1321		this.submissionQueue = new LinkedTransferQueue<ForkJoinTask<?>>();
1322		this.workerLock = new ReentrantLock();
1323	<	this.terminationLatch = new CountDownLatch(1);
1324	<	// Start first worker; remaining workers added upon first submission
1168	<	workerCounts = ONE_RUNNING \| ONE_TOTAL;
1169	<	addWorker();
1323	>	this.termination = new Phaser(1);
1324	>	this.poolNumber = poolNumberGenerator.incrementAndGet();
1325		}
1326
1327		/**
#	Line 1174 \| Line 1329 \| public class ForkJoinPool extends Abstra
1329		* @param pc the initial parallelism level
1330		*/
1331		private static int initialArraySizeFor(int pc) {
1332	<	// See Hackers Delight, sec 3.2. We know MAX_THREADS < (1 >>> 16)
1333	<	int size = pc < MAX_THREADS ? pc + 1 : MAX_THREADS;
1332	>	// If possible, initially allocate enough space for one spare
1333	>	int size = pc < MAX_WORKERS ? pc + 1 : MAX_WORKERS;
1334	>	// See Hackers Delight, sec 3.2. We know MAX_WORKERS < (1 >>> 16)
1335		size \|= size >>> 1;
1336		size \|= size >>> 2;
1337		size \|= size >>> 4;
#	Line 1186 \| Line 1342 \| public class ForkJoinPool extends Abstra
1342		// Execution methods
1343
1344		/**
1345	<	* Common code for execute, invoke and submit
1345	>	* Submits task and creates, starts, or resumes some workers if necessary
1346		*/
1347		private <T> void doSubmit(ForkJoinTask<T> task) {
1192	–	if (task == null)
1193	–	throw new NullPointerException();
1194	–	if (runState >= SHUTDOWN)
1195	–	throw new RejectedExecutionException();
1348		submissionQueue.offer(task);
1349	<	advanceEventCount();
1350	<	releaseWaiters();
1351	<	if ((workerCounts >>> TOTAL_COUNT_SHIFT) < parallelism)
1200	<	ensureEnoughTotalWorkers();
1349	>	int c; // try to increment event count -- CAS failure OK
1350	>	UNSAFE.compareAndSwapInt(this, eventCountOffset, c = eventCount, c+1);
1351	>	helpMaintainParallelism();
1352		}
1353
1354		/**
#	Line 1210 \| Line 1361 \| public class ForkJoinPool extends Abstra
1361		* scheduled for execution
1362		*/
1363		public <T> T invoke(ForkJoinTask<T> task) {
1364	<	doSubmit(task);
1365	<	return task.join();
1364	>	if (task == null)
1365	>	throw new NullPointerException();
1366	>	if (runState >= SHUTDOWN)
1367	>	throw new RejectedExecutionException();
1368	>	Thread t = Thread.currentThread();
1369	>	if ((t instanceof ForkJoinWorkerThread) &&
1370	>	((ForkJoinWorkerThread)t).pool == this)
1371	>	return task.invoke(); // bypass submit if in same pool
1372	>	else {
1373	>	doSubmit(task);
1374	>	return task.join();
1375	>	}
1376	>	}
1377	>
1378	>	/**
1379	>	* Unless terminating, forks task if within an ongoing FJ
1380	>	* computation in the current pool, else submits as external task.
1381	>	*/
1382	>	private <T> void forkOrSubmit(ForkJoinTask<T> task) {
1383	>	if (runState >= SHUTDOWN)
1384	>	throw new RejectedExecutionException();
1385	>	Thread t = Thread.currentThread();
1386	>	if ((t instanceof ForkJoinWorkerThread) &&
1387	>	((ForkJoinWorkerThread)t).pool == this)
1388	>	task.fork();
1389	>	else
1390	>	doSubmit(task);
1391		}
1392
1393		/**
#	Line 1223 \| Line 1399 \| public class ForkJoinPool extends Abstra
1399		* scheduled for execution
1400		*/
1401		public void execute(ForkJoinTask<?> task) {
1402	<	doSubmit(task);
1402	>	if (task == null)
1403	>	throw new NullPointerException();
1404	>	forkOrSubmit(task);
1405		}
1406
1407		// AbstractExecutorService methods
#	Line 1234 \| Line 1412 \| public class ForkJoinPool extends Abstra
1412		* scheduled for execution
1413		*/
1414		public void execute(Runnable task) {
1415	+	if (task == null)
1416	+	throw new NullPointerException();
1417		ForkJoinTask<?> job;
1418		if (task instanceof ForkJoinTask<?>) // avoid re-wrap
1419		job = (ForkJoinTask<?>) task;
1420		else
1421		job = ForkJoinTask.adapt(task, null);
1422	<	doSubmit(job);
1422	>	forkOrSubmit(job);
1423	>	}
1424	>
1425	>	/**
1426	>	* Submits a ForkJoinTask for execution.
1427	>	*
1428	>	* @param task the task to submit
1429	>	* @return the task
1430	>	* @throws NullPointerException if the task is null
1431	>	* @throws RejectedExecutionException if the task cannot be
1432	>	* scheduled for execution
1433	>	*/
1434	>	public <T> ForkJoinTask<T> submit(ForkJoinTask<T> task) {
1435	>	if (task == null)
1436	>	throw new NullPointerException();
1437	>	forkOrSubmit(task);
1438	>	return task;
1439		}
1440
1441		/**
#	Line 1248 \| Line 1444 \| public class ForkJoinPool extends Abstra
1444		* scheduled for execution
1445		*/
1446		public <T> ForkJoinTask<T> submit(Callable<T> task) {
1447	+	if (task == null)
1448	+	throw new NullPointerException();
1449		ForkJoinTask<T> job = ForkJoinTask.adapt(task);
1450	<	doSubmit(job);
1450	>	forkOrSubmit(job);
1451		return job;
1452		}
1453
#	Line 1259 \| Line 1457 \| public class ForkJoinPool extends Abstra
1457		* scheduled for execution
1458		*/
1459		public <T> ForkJoinTask<T> submit(Runnable task, T result) {
1460	+	if (task == null)
1461	+	throw new NullPointerException();
1462		ForkJoinTask<T> job = ForkJoinTask.adapt(task, result);
1463	<	doSubmit(job);
1463	>	forkOrSubmit(job);
1464		return job;
1465		}
1466
#	Line 1270 \| Line 1470 \| public class ForkJoinPool extends Abstra
1470		* scheduled for execution
1471		*/
1472		public ForkJoinTask<?> submit(Runnable task) {
1473	+	if (task == null)
1474	+	throw new NullPointerException();
1475		ForkJoinTask<?> job;
1476		if (task instanceof ForkJoinTask<?>) // avoid re-wrap
1477		job = (ForkJoinTask<?>) task;
1478		else
1479		job = ForkJoinTask.adapt(task, null);
1480	<	doSubmit(job);
1480	>	forkOrSubmit(job);
1481		return job;
1482		}
1483
1484		/**
1283	–	* Submits a ForkJoinTask for execution.
1284	–	*
1285	–	* @param task the task to submit
1286	–	* @return the task
1287	–	* @throws NullPointerException if the task is null
1288	–	* @throws RejectedExecutionException if the task cannot be
1289	–	* scheduled for execution
1290	–	*/
1291	–	public <T> ForkJoinTask<T> submit(ForkJoinTask<T> task) {
1292	–	doSubmit(task);
1293	–	return task;
1294	–	}
1295	–
1296	–	/**
1485		* @throws NullPointerException {@inheritDoc}
1486		* @throws RejectedExecutionException {@inheritDoc}
1487		*/
#	Line 1305 \| Line 1493 \| public class ForkJoinPool extends Abstra
1493		invoke(new InvokeAll<T>(forkJoinTasks));
1494
1495		@SuppressWarnings({"unchecked", "rawtypes"})
1496	<	List<Future<T>> futures = (List<Future<T>>) (List) forkJoinTasks;
1496	>	List<Future<T>> futures = (List<Future<T>>) (List) forkJoinTasks;
1497		return futures;
1498		}
1499
#	Line 1335 \| Line 1523 \| public class ForkJoinPool extends Abstra
1523		* @return the handler, or {@code null} if none
1524		*/
1525		public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() {
1338	–	workerCountReadFence();
1526		return ueh;
1527		}
1528
1529		/**
1343	–	* Sets the handler for internal worker threads that terminate due
1344	–	* to unrecoverable errors encountered while executing tasks.
1345	–	* Unless set, the current default or ThreadGroup handler is used
1346	–	* as handler.
1347	–	*
1348	–	* @param h the new handler
1349	–	* @return the old handler, or {@code null} if none
1350	–	* @throws SecurityException if a security manager exists and
1351	–	* the caller is not permitted to modify threads
1352	–	* because it does not hold {@link
1353	–	* java.lang.RuntimePermission}{@code ("modifyThread")}
1354	–	*/
1355	–	public Thread.UncaughtExceptionHandler
1356	–	setUncaughtExceptionHandler(Thread.UncaughtExceptionHandler h) {
1357	–	checkPermission();
1358	–	workerCountReadFence();
1359	–	Thread.UncaughtExceptionHandler old = ueh;
1360	–	if (h != old) {
1361	–	ueh = h;
1362	–	workerCountWriteFence();
1363	–	for (ForkJoinWorkerThread w : workers) {
1364	–	if (w != null)
1365	–	w.setUncaughtExceptionHandler(h);
1366	–	}
1367	–	}
1368	–	return old;
1369	–	}
1370	–
1371	–	/**
1372	–	* Sets the target parallelism level of this pool.
1373	–	*
1374	–	* @param parallelism the target parallelism
1375	–	* @throws IllegalArgumentException if parallelism less than or
1376	–	* equal to zero or greater than maximum size bounds
1377	–	* @throws SecurityException if a security manager exists and
1378	–	* the caller is not permitted to modify threads
1379	–	* because it does not hold {@link
1380	–	* java.lang.RuntimePermission}{@code ("modifyThread")}
1381	–	*/
1382	–	public void setParallelism(int parallelism) {
1383	–	checkPermission();
1384	–	if (parallelism <= 0 \|\| parallelism > maxPoolSize)
1385	–	throw new IllegalArgumentException();
1386	–	workerCountReadFence();
1387	–	int pc = this.parallelism;
1388	–	if (pc != parallelism) {
1389	–	this.parallelism = parallelism;
1390	–	workerCountWriteFence();
1391	–	// Release spares. If too many, some will die after re-suspend
1392	–	for (ForkJoinWorkerThread w : workers) {
1393	–	if (w != null && w.tryUnsuspend()) {
1394	–	updateRunningCount(1);
1395	–	LockSupport.unpark(w);
1396	–	}
1397	–	}
1398	–	ensureEnoughTotalWorkers();
1399	–	advanceEventCount();
1400	–	releaseWaiters(); // force config recheck by existing workers
1401	–	}
1402	–	}
1403	–
1404	–	/**
1530		* Returns the targeted parallelism level of this pool.
1531		*
1532		* @return the targeted parallelism level of this pool
1533		*/
1534		public int getParallelism() {
1410	–	// workerCountReadFence(); // inlined below
1411	–	int ignore = workerCounts;
1535		return parallelism;
1536		}
1537
1538		/**
1539		* Returns the number of worker threads that have started but not
1540	<	* yet terminated. This result returned by this method may differ
1540	>	* yet terminated. The result returned by this method may differ
1541		* from {@link #getParallelism} when threads are created to
1542		* maintain parallelism when others are cooperatively blocked.
1543		*
#	Line 1425 \| Line 1548 \| public class ForkJoinPool extends Abstra
1548		}
1549
1550		/**
1428	–	* Returns the maximum number of threads allowed to exist in the
1429	–	* pool. Unless set using {@link #setMaximumPoolSize}, the
1430	–	* maximum is an implementation-defined value designed only to
1431	–	* prevent runaway growth.
1432	–	*
1433	–	* @return the maximum
1434	–	*/
1435	–	public int getMaximumPoolSize() {
1436	–	workerCountReadFence();
1437	–	return maxPoolSize;
1438	–	}
1439	–
1440	–	/**
1441	–	* Sets the maximum number of threads allowed to exist in the
1442	–	* pool. The given value should normally be greater than or equal
1443	–	* to the {@link #getParallelism parallelism} level. Setting this
1444	–	* value has no effect on current pool size. It controls
1445	–	* construction of new threads.
1446	–	*
1447	–	* @throws IllegalArgumentException if negative or greater than
1448	–	* internal implementation limit
1449	–	*/
1450	–	public void setMaximumPoolSize(int newMax) {
1451	–	if (newMax < 0 \|\| newMax > MAX_THREADS)
1452	–	throw new IllegalArgumentException();
1453	–	maxPoolSize = newMax;
1454	–	workerCountWriteFence();
1455	–	}
1456	–
1457	–	/**
1458	–	* Returns {@code true} if this pool dynamically maintains its
1459	–	* target parallelism level. If false, new threads are added only
1460	–	* to avoid possible starvation. This setting is by default true.
1461	–	*
1462	–	* @return {@code true} if maintains parallelism
1463	–	*/
1464	–	public boolean getMaintainsParallelism() {
1465	–	workerCountReadFence();
1466	–	return maintainsParallelism;
1467	–	}
1468	–
1469	–	/**
1470	–	* Sets whether this pool dynamically maintains its target
1471	–	* parallelism level. If false, new threads are added only to
1472	–	* avoid possible starvation.
1473	–	*
1474	–	* @param enable {@code true} to maintain parallelism
1475	–	*/
1476	–	public void setMaintainsParallelism(boolean enable) {
1477	–	maintainsParallelism = enable;
1478	–	workerCountWriteFence();
1479	–	}
1480	–
1481	–	/**
1482	–	* Establishes local first-in-first-out scheduling mode for forked
1483	–	* tasks that are never joined. This mode may be more appropriate
1484	–	* than default locally stack-based mode in applications in which
1485	–	* worker threads only process asynchronous tasks. This method is
1486	–	* designed to be invoked only when the pool is quiescent, and
1487	–	* typically only before any tasks are submitted. The effects of
1488	–	* invocations at other times may be unpredictable.
1489	–	*
1490	–	* @param async if {@code true}, use locally FIFO scheduling
1491	–	* @return the previous mode
1492	–	* @see #getAsyncMode
1493	–	*/
1494	–	public boolean setAsyncMode(boolean async) {
1495	–	workerCountReadFence();
1496	–	boolean oldMode = locallyFifo;
1497	–	if (oldMode != async) {
1498	–	locallyFifo = async;
1499	–	workerCountWriteFence();
1500	–	for (ForkJoinWorkerThread w : workers) {
1501	–	if (w != null)
1502	–	w.setAsyncMode(async);
1503	–	}
1504	–	}
1505	–	return oldMode;
1506	–	}
1507	–
1508	–	/**
1551		* Returns {@code true} if this pool uses local first-in-first-out
1552		* scheduling mode for forked tasks that are never joined.
1553		*
1554		* @return {@code true} if this pool uses async mode
1513	–	* @see #setAsyncMode
1555		*/
1556		public boolean getAsyncMode() {
1516	–	workerCountReadFence();
1557		return locallyFifo;
1558		}
1559
#	Line 1582 \| Line 1622 \| public class ForkJoinPool extends Abstra
1622		*/
1623		public long getQueuedTaskCount() {
1624		long count = 0;
1625	<	for (ForkJoinWorkerThread w : workers) {
1625	>	for (ForkJoinWorkerThread w : workers)
1626		if (w != null)
1627		count += w.getQueueSize();
1588	–	}
1628		return count;
1629		}
1630
#	Line 1639 \| Line 1678 \| public class ForkJoinPool extends Abstra
1678		* @return the number of elements transferred
1679		*/
1680		protected int drainTasksTo(Collection<? super ForkJoinTask<?>> c) {
1681	<	int n = submissionQueue.drainTo(c);
1682	<	for (ForkJoinWorkerThread w : workers) {
1681	>	int count = submissionQueue.drainTo(c);
1682	>	for (ForkJoinWorkerThread w : workers)
1683		if (w != null)
1684	<	n += w.drainTasksTo(c);
1685	<	}
1647	<	return n;
1684	>	count += w.drainTasksTo(c);
1685	>	return count;
1686		}
1687
1688		/**
#	Line 1747 \| Line 1785 \| public class ForkJoinPool extends Abstra
1785		}
1786
1787		/**
1788	+	* Returns true if terminating or terminated. Used by ForkJoinWorkerThread.
1789	+	*/
1790	+	final boolean isAtLeastTerminating() {
1791	+	return runState >= TERMINATING;
1792	+	}
1793	+
1794	+	/**
1795		* Returns {@code true} if this pool has been shut down.
1796		*
1797		* @return {@code true} if this pool has been shut down
#	Line 1768 \| Line 1813 \| public class ForkJoinPool extends Abstra
1813		*/
1814		public boolean awaitTermination(long timeout, TimeUnit unit)
1815		throws InterruptedException {
1816	<	return terminationLatch.await(timeout, unit);
1816	>	try {
1817	>	termination.awaitAdvanceInterruptibly(0, timeout, unit);
1818	>	} catch (TimeoutException ex) {
1819	>	return false;
1820	>	}
1821	>	return true;
1822		}
1823
1824		/**
1825		* Interface for extending managed parallelism for tasks running
1826		* in {@link ForkJoinPool}s.
1827		*
1828	<	* <p>A {@code ManagedBlocker} provides two methods.
1829	<	* Method {@code isReleasable} must return {@code true} if
1830	<	* blocking is not necessary. Method {@code block} blocks the
1831	<	* current thread if necessary (perhaps internally invoking
1832	<	* {@code isReleasable} before actually blocking).
1828	>	* <p>A {@code ManagedBlocker} provides two methods. Method
1829	>	* {@code isReleasable} must return {@code true} if blocking is
1830	>	* not necessary. Method {@code block} blocks the current thread
1831	>	* if necessary (perhaps internally invoking {@code isReleasable}
1832	>	* before actually blocking). The unusual methods in this API
1833	>	* accommodate synchronizers that may, but don't usually, block
1834	>	* for long periods. Similarly, they allow more efficient internal
1835	>	* handling of cases in which additional workers may be, but
1836	>	* usually are not, needed to ensure sufficient parallelism.
1837	>	* Toward this end, implementations of method {@code isReleasable}
1838	>	* must be amenable to repeated invocation.
1839		*
1840		* <p>For example, here is a ManagedBlocker based on a
1841		* ReentrantLock:
#	Line 1797 \| Line 1853 \| public class ForkJoinPool extends Abstra
1853		* return hasLock \|\| (hasLock = lock.tryLock());
1854		* }
1855		* }}</pre>
1856	+	*
1857	+	* <p>Here is a class that possibly blocks waiting for an
1858	+	* item on a given queue:
1859	+	* <pre> {@code
1860	+	* class QueueTaker<E> implements ManagedBlocker {
1861	+	* final BlockingQueue<E> queue;
1862	+	* volatile E item = null;
1863	+	* QueueTaker(BlockingQueue<E> q) { this.queue = q; }
1864	+	* public boolean block() throws InterruptedException {
1865	+	* if (item == null)
1866	+	* item = queue.take();
1867	+	* return true;
1868	+	* }
1869	+	* public boolean isReleasable() {
1870	+	* return item != null \|\| (item = queue.poll()) != null;
1871	+	* }
1872	+	* public E getItem() { // call after pool.managedBlock completes
1873	+	* return item;
1874	+	* }
1875	+	* }}</pre>
1876		*/
1877		public static interface ManagedBlocker {
1878		/**
#	Line 1820 \| Line 1896 \| public class ForkJoinPool extends Abstra
1896		* Blocks in accord with the given blocker. If the current thread
1897		* is a {@link ForkJoinWorkerThread}, this method possibly
1898		* arranges for a spare thread to be activated if necessary to
1899	<	* ensure parallelism while the current thread is blocked.
1824	<	*
1825	<	* <p>If {@code maintainParallelism} is {@code true} and the pool
1826	<	* supports it ({@link #getMaintainsParallelism}), this method
1827	<	* attempts to maintain the pool's nominal parallelism. Otherwise
1828	<	* it activates a thread only if necessary to avoid complete
1829	<	* starvation. This option may be preferable when blockages use
1830	<	* timeouts, or are almost always brief.
1899	>	* ensure sufficient parallelism while the current thread is blocked.
1900		*
1901		* <p>If the caller is not a {@link ForkJoinTask}, this method is
1902		* behaviorally equivalent to
#	Line 1841 \| Line 1910 \| public class ForkJoinPool extends Abstra
1910		* first be expanded to ensure parallelism, and later adjusted.
1911		*
1912		* @param blocker the blocker
1844	–	* @param maintainParallelism if {@code true} and supported by
1845	–	* this pool, attempt to maintain the pool's nominal parallelism;
1846	–	* otherwise activate a thread only if necessary to avoid
1847	–	* complete starvation.
1913		* @throws InterruptedException if blocker.block did so
1914		*/
1915	<	public static void managedBlock(ManagedBlocker blocker,
1851	<	boolean maintainParallelism)
1915	>	public static void managedBlock(ManagedBlocker blocker)
1916		throws InterruptedException {
1917		Thread t = Thread.currentThread();
1918	<	if (t instanceof ForkJoinWorkerThread)
1919	<	((ForkJoinWorkerThread) t).pool.
1920	<	doBlock(blocker, maintainParallelism);
1921	<	else
1922	<	awaitBlocker(blocker);
1923	<	}
1924	<
1861	<	/**
1862	<	* Performs Non-FJ blocking
1863	<	*/
1864	<	private static void awaitBlocker(ManagedBlocker blocker)
1865	<	throws InterruptedException {
1866	<	do {} while (!blocker.isReleasable() && !blocker.block());
1918	>	if (t instanceof ForkJoinWorkerThread) {
1919	>	ForkJoinWorkerThread w = (ForkJoinWorkerThread) t;
1920	>	w.pool.awaitBlocker(blocker);
1921	>	}
1922	>	else {
1923	>	do {} while (!blocker.isReleasable() && !blocker.block());
1924	>	}
1925		}
1926
1927		// AbstractExecutorService overrides. These rely on undocumented
#	Line 1888 \| Line 1946 \| public class ForkJoinPool extends Abstra
1946		private static final long eventCountOffset =
1947		objectFieldOffset("eventCount", ForkJoinPool.class);
1948		private static final long eventWaitersOffset =
1949	<	objectFieldOffset("eventWaiters",ForkJoinPool.class);
1949	>	objectFieldOffset("eventWaiters", ForkJoinPool.class);
1950		private static final long stealCountOffset =
1951	<	objectFieldOffset("stealCount",ForkJoinPool.class);
1952	<
1951	>	objectFieldOffset("stealCount", ForkJoinPool.class);
1952	>	private static final long spareWaitersOffset =
1953	>	objectFieldOffset("spareWaiters", ForkJoinPool.class);
1954
1955		private static long objectFieldOffset(String field, Class<?> klazz) {
1956		try {

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Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents): Revision 1.53 by dl, Mon Apr 5 15:52:26 2010 UTC vs. Revision 1.85 by dl, Sun Nov 21 13:55:04 2010 UTC

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Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.53 by dl, Mon Apr 5 15:52:26 2010 UTC vs.
Revision 1.85 by dl, Sun Nov 21 13:55:04 2010 UTC