19 |
|
import java.util.concurrent.RejectedExecutionException; |
20 |
|
import java.util.concurrent.RunnableFuture; |
21 |
|
import java.util.concurrent.TimeUnit; |
22 |
– |
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; |
101 |
|
* daemon} mode, there is typically no need to explicitly {@link |
102 |
|
* #shutdown} such a pool upon program exit. |
103 |
|
* |
104 |
< |
* <pre> |
104 |
> |
* <pre> {@code |
105 |
|
* static final ForkJoinPool mainPool = new ForkJoinPool(); |
106 |
|
* ... |
107 |
|
* public void sort(long[] array) { |
108 |
|
* mainPool.invoke(new SortTask(array, 0, array.length)); |
109 |
< |
* } |
111 |
< |
* </pre> |
109 |
> |
* }}</pre> |
110 |
|
* |
111 |
|
* <p><b>Implementation notes</b>: This implementation restricts the |
112 |
|
* maximum number of running threads to 32767. Attempts to create |
290 |
|
* "terminate" status, cancels all unprocessed tasks, and wakes up |
291 |
|
* all waiting workers. Detecting whether termination should |
292 |
|
* commence after a non-abrupt shutdown() call requires more work |
293 |
< |
* and bookkeeping. We need consensus about quiesence (i.e., that |
293 |
> |
* and bookkeeping. We need consensus about quiescence (i.e., that |
294 |
|
* there is no more work) which is reflected in active counts so |
295 |
|
* long as there are no current blockers, as well as possible |
296 |
|
* re-evaluations during independent changes in blocking or |
465 |
|
/** |
466 |
|
* Main pool control -- a long packed with: |
467 |
|
* AC: Number of active running workers minus target parallelism (16 bits) |
468 |
< |
* TC: Number of total workers minus target parallelism (16bits) |
468 |
> |
* TC: Number of total workers minus target parallelism (16 bits) |
469 |
|
* ST: true if pool is terminating (1 bit) |
470 |
|
* EC: the wait count of top waiting thread (15 bits) |
471 |
|
* ID: ~poolIndex of top of Treiber stack of waiting threads (16 bits) |
545 |
|
volatile boolean shutdown; |
546 |
|
|
547 |
|
/** |
548 |
< |
* True if use local fifo, not default lifo, for local polling |
549 |
< |
* Read by, and replicated by ForkJoinWorkerThreads |
548 |
> |
* True if use local fifo, not default lifo, for local polling. |
549 |
> |
* Read by, and replicated by ForkJoinWorkerThreads. |
550 |
|
*/ |
551 |
|
final boolean locallyFifo; |
552 |
|
|
784 |
|
long nc = (long)(v & E_MASK) | ((c - AC_UNIT) & (AC_MASK|TC_MASK)); |
785 |
|
if (ctl != c || !UNSAFE.compareAndSwapLong(this, ctlOffset, c, nc)) { |
786 |
|
long d = ctl; // return true if lost to a deq, to force scan |
787 |
< |
return (int)d != (int)c && ((d - c) & AC_MASK) >= 0L; |
787 |
> |
return (int)d != (int)c && (d & AC_MASK) >= (c & AC_MASK); |
788 |
|
} |
789 |
|
for (int sc = w.stealCount; sc != 0;) { // accumulate stealCount |
790 |
|
long s = stealCount; |
947 |
|
int pc = parallelism; |
948 |
|
do { |
949 |
|
ForkJoinWorkerThread[] ws; ForkJoinWorkerThread w; |
950 |
< |
int e, ac, tc, rc, i; |
950 |
> |
int e, ac, tc, i; |
951 |
|
long c = ctl; |
952 |
|
int u = (int)(c >>> 32); |
953 |
|
if ((e = (int)c) < 0) { |
987 |
|
} |
988 |
|
|
989 |
|
/** |
990 |
< |
* Decrements blockedCount and increments active count |
990 |
> |
* Decrements blockedCount and increments active count. |
991 |
|
*/ |
992 |
|
private void postBlock() { |
993 |
|
long c; |
1005 |
|
* @param joinMe the task |
1006 |
|
*/ |
1007 |
|
final void tryAwaitJoin(ForkJoinTask<?> joinMe) { |
1010 |
– |
int s; |
1008 |
|
Thread.interrupted(); // clear interrupts before checking termination |
1009 |
|
if (joinMe.status >= 0) { |
1010 |
|
if (tryPreBlock()) { |
1018 |
|
|
1019 |
|
/** |
1020 |
|
* Possibly blocks the given worker waiting for joinMe to |
1021 |
< |
* complete or timeout |
1021 |
> |
* complete or timeout. |
1022 |
|
* |
1023 |
|
* @param joinMe the task |
1024 |
|
* @param millis the wait time for underlying Object.wait |
1054 |
|
} |
1055 |
|
|
1056 |
|
/** |
1057 |
< |
* If necessary, compensates for blocker, and blocks |
1057 |
> |
* If necessary, compensates for blocker, and blocks. |
1058 |
|
*/ |
1059 |
|
private void awaitBlocker(ManagedBlocker blocker) |
1060 |
|
throws InterruptedException { |
1070 |
|
} |
1071 |
|
} |
1072 |
|
|
1073 |
< |
// Creating, registering and deregistring workers |
1073 |
> |
// Creating, registering and deregistering workers |
1074 |
|
|
1075 |
|
/** |
1076 |
|
* Tries to create and start a worker; minimally rolls back counts |
1321 |
|
// misc ForkJoinWorkerThread support |
1322 |
|
|
1323 |
|
/** |
1324 |
< |
* Increment or decrement quiescerCount. Needed only to prevent |
1324 |
> |
* Increments or decrements quiescerCount. Needed only to prevent |
1325 |
|
* triggering shutdown if a worker is transiently inactive while |
1326 |
|
* checking quiescence. |
1327 |
|
* |
1334 |
|
} |
1335 |
|
|
1336 |
|
/** |
1337 |
< |
* Directly increment or decrement active count without |
1338 |
< |
* queuing. This method is used to transiently assert inactivation |
1339 |
< |
* while checking quiescence. |
1337 |
> |
* Directly increments or decrements active count without queuing. |
1338 |
> |
* This method is used to transiently assert inactivation while |
1339 |
> |
* checking quiescence. |
1340 |
|
* |
1341 |
|
* @param delta 1 for increment, -1 for decrement |
1342 |
|
*/ |
1343 |
|
final void addActiveCount(int delta) { |
1344 |
< |
long d = delta < 0 ? -AC_UNIT : AC_UNIT; |
1344 |
> |
long d = (long)delta << AC_SHIFT; |
1345 |
|
long c; |
1346 |
< |
do {} while (!UNSAFE.compareAndSwapLong(this, ctlOffset, c = ctl, |
1347 |
< |
((c + d) & AC_MASK) | |
1351 |
< |
(c & ~AC_MASK))); |
1346 |
> |
do {} while (!UNSAFE.compareAndSwapLong(this, ctlOffset, |
1347 |
> |
c = ctl, c + d)); |
1348 |
|
} |
1349 |
|
|
1350 |
|
/** |
2114 |
|
modifyThreadPermission = new RuntimePermission("modifyThread"); |
2115 |
|
defaultForkJoinWorkerThreadFactory = |
2116 |
|
new DefaultForkJoinWorkerThreadFactory(); |
2121 |
– |
int s; |
2117 |
|
try { |
2118 |
|
UNSAFE = getUnsafe(); |
2119 |
|
Class<?> k = ForkJoinPool.class; |
2129 |
|
(k.getDeclaredField("scanGuard")); |
2130 |
|
nextWorkerNumberOffset = UNSAFE.objectFieldOffset |
2131 |
|
(k.getDeclaredField("nextWorkerNumber")); |
2137 |
– |
Class<?> a = ForkJoinTask[].class; |
2138 |
– |
ABASE = UNSAFE.arrayBaseOffset(a); |
2139 |
– |
s = UNSAFE.arrayIndexScale(a); |
2132 |
|
} catch (Exception e) { |
2133 |
|
throw new Error(e); |
2134 |
|
} |
2135 |
+ |
Class<?> a = ForkJoinTask[].class; |
2136 |
+ |
ABASE = UNSAFE.arrayBaseOffset(a); |
2137 |
+ |
int s = UNSAFE.arrayIndexScale(a); |
2138 |
|
if ((s & (s-1)) != 0) |
2139 |
|
throw new Error("data type scale not a power of two"); |
2140 |
|
ASHIFT = 31 - Integer.numberOfLeadingZeros(s); |