| 5 |
|
*/ |
| 6 |
|
|
| 7 |
|
package jsr166y; |
| 8 |
< |
import java.util.*; |
| 8 |
> |
|
| 9 |
|
import java.util.concurrent.*; |
| 10 |
< |
import java.util.concurrent.atomic.*; |
| 11 |
< |
import java.util.concurrent.locks.*; |
| 12 |
< |
import sun.misc.Unsafe; |
| 13 |
< |
import java.lang.reflect.*; |
| 10 |
> |
|
| 11 |
> |
import java.util.Collection; |
| 12 |
|
|
| 13 |
|
/** |
| 14 |
|
* A thread managed by a {@link ForkJoinPool}. This class is |
| 15 |
|
* subclassable solely for the sake of adding functionality -- there |
| 16 |
< |
* are no overridable methods dealing with scheduling or |
| 17 |
< |
* execution. However, you can override initialization and termination |
| 18 |
< |
* cleanup methods surrounding the main task processing loop. If you |
| 19 |
< |
* do create such a subclass, you will also need to supply a custom |
| 20 |
< |
* ForkJoinWorkerThreadFactory to use it in a ForkJoinPool. |
| 21 |
< |
* |
| 16 |
> |
* are no overridable methods dealing with scheduling or execution. |
| 17 |
> |
* However, you can override initialization and termination methods |
| 18 |
> |
* surrounding the main task processing loop. If you do create such a |
| 19 |
> |
* subclass, you will also need to supply a custom {@link |
| 20 |
> |
* ForkJoinWorkerThreadFactory} to use it in a {@code ForkJoinPool}. |
| 21 |
> |
* |
| 22 |
> |
* @since 1.7 |
| 23 |
> |
* @author Doug Lea |
| 24 |
|
*/ |
| 25 |
|
public class ForkJoinWorkerThread extends Thread { |
| 26 |
|
/* |
| 44 |
|
* of tasks. To accomplish this, we shift the CAS arbitrating pop |
| 45 |
|
* vs deq (steal) from being on the indices ("base" and "sp") to |
| 46 |
|
* the slots themselves (mainly via method "casSlotNull()"). So, |
| 47 |
< |
* both a successful pop and deq mainly entail CAS'ing a nonnull |
| 47 |
> |
* both a successful pop and deq mainly entail CAS'ing a non-null |
| 48 |
|
* slot to null. Because we rely on CASes of references, we do |
| 49 |
|
* not need tag bits on base or sp. They are simple ints as used |
| 50 |
|
* in any circular array-based queue (see for example ArrayDeque). |
| 56 |
|
* considered individually, is not wait-free. One thief cannot |
| 57 |
|
* successfully continue until another in-progress one (or, if |
| 58 |
|
* previously empty, a push) completes. However, in the |
| 59 |
< |
* aggregate, we ensure at least probablistic non-blockingness. If |
| 59 |
> |
* aggregate, we ensure at least probabilistic non-blockingness. If |
| 60 |
|
* an attempted steal fails, a thief always chooses a different |
| 61 |
|
* random victim target to try next. So, in order for one thief to |
| 62 |
|
* progress, it suffices for any in-progress deq or new push on |
| 65 |
|
* which gives threads a chance to activate if necessary before |
| 66 |
|
* stealing (see below). |
| 67 |
|
* |
| 68 |
+ |
* This approach also enables support for "async mode" where local |
| 69 |
+ |
* task processing is in FIFO, not LIFO order; simply by using a |
| 70 |
+ |
* version of deq rather than pop when locallyFifo is true (as set |
| 71 |
+ |
* by the ForkJoinPool). This allows use in message-passing |
| 72 |
+ |
* frameworks in which tasks are never joined. |
| 73 |
+ |
* |
| 74 |
|
* Efficient implementation of this approach currently relies on |
| 75 |
|
* an uncomfortable amount of "Unsafe" mechanics. To maintain |
| 76 |
|
* correct orderings, reads and writes of variable base require |
| 81 |
|
* push) require store order and CASes (in pop and deq) require |
| 82 |
|
* (volatile) CAS semantics. Since these combinations aren't |
| 83 |
|
* supported using ordinary volatiles, the only way to accomplish |
| 84 |
< |
* these effciently is to use direct Unsafe calls. (Using external |
| 84 |
> |
* these efficiently is to use direct Unsafe calls. (Using external |
| 85 |
|
* AtomicIntegers and AtomicReferenceArrays for the indices and |
| 86 |
|
* array is significantly slower because of memory locality and |
| 87 |
|
* indirection effects.) Further, performance on most platforms is |
| 143 |
|
private static final int MAXIMUM_QUEUE_CAPACITY = 1 << 28; |
| 144 |
|
|
| 145 |
|
/** |
| 146 |
< |
* The pool this thread works in. Accessed directly by ForkJoinTask |
| 146 |
> |
* The pool this thread works in. Accessed directly by ForkJoinTask. |
| 147 |
|
*/ |
| 148 |
|
final ForkJoinPool pool; |
| 149 |
|
|
| 171 |
|
* Activity status. When true, this worker is considered active. |
| 172 |
|
* Must be false upon construction. It must be true when executing |
| 173 |
|
* tasks, and BEFORE stealing a task. It must be false before |
| 174 |
< |
* calling pool.sync |
| 174 |
> |
* calling pool.sync. |
| 175 |
|
*/ |
| 176 |
|
private boolean active; |
| 177 |
|
|
| 194 |
|
|
| 195 |
|
/** |
| 196 |
|
* Index of this worker in pool array. Set once by pool before |
| 197 |
< |
* running, and accessed directly by pool during cleanup etc |
| 197 |
> |
* running, and accessed directly by pool during cleanup etc. |
| 198 |
|
*/ |
| 199 |
|
int poolIndex; |
| 200 |
|
|
| 205 |
|
long lastEventCount; |
| 206 |
|
|
| 207 |
|
/** |
| 208 |
+ |
* True if use local fifo, not default lifo, for local polling |
| 209 |
+ |
*/ |
| 210 |
+ |
private boolean locallyFifo; |
| 211 |
+ |
|
| 212 |
+ |
/** |
| 213 |
|
* Creates a ForkJoinWorkerThread operating in the given pool. |
| 214 |
+ |
* |
| 215 |
|
* @param pool the pool this thread works in |
| 216 |
|
* @throws NullPointerException if pool is null |
| 217 |
|
*/ |
| 222 |
|
// Remaining initialization is deferred to onStart |
| 223 |
|
} |
| 224 |
|
|
| 225 |
< |
// Public access methods |
| 225 |
> |
// Public access methods |
| 226 |
|
|
| 227 |
|
/** |
| 228 |
< |
* Returns the pool hosting this thread |
| 228 |
> |
* Returns the pool hosting this thread. |
| 229 |
> |
* |
| 230 |
|
* @return the pool |
| 231 |
|
*/ |
| 232 |
|
public ForkJoinPool getPool() { |
| 239 |
|
* threads (minus one) that have ever been created in the pool. |
| 240 |
|
* This method may be useful for applications that track status or |
| 241 |
|
* collect results per-worker rather than per-task. |
| 242 |
< |
* @return the index number. |
| 242 |
> |
* |
| 243 |
> |
* @return the index number |
| 244 |
|
*/ |
| 245 |
|
public int getPoolIndex() { |
| 246 |
|
return poolIndex; |
| 247 |
|
} |
| 248 |
|
|
| 249 |
+ |
/** |
| 250 |
+ |
* Establishes local first-in-first-out scheduling mode for forked |
| 251 |
+ |
* tasks that are never joined. |
| 252 |
+ |
* |
| 253 |
+ |
* @param async if true, use locally FIFO scheduling |
| 254 |
+ |
*/ |
| 255 |
+ |
void setAsyncMode(boolean async) { |
| 256 |
+ |
locallyFifo = async; |
| 257 |
+ |
} |
| 258 |
|
|
| 259 |
|
// Runstate management |
| 260 |
|
|
| 271 |
|
final boolean shutdownNow() { return transitionRunStateTo(TERMINATING); } |
| 272 |
|
|
| 273 |
|
/** |
| 274 |
< |
* Transition to at least the given state. Return true if not |
| 275 |
< |
* already at least given state. |
| 274 |
> |
* Transitions to at least the given state. |
| 275 |
> |
* |
| 276 |
> |
* @return {@code true} if not already at least at given state |
| 277 |
|
*/ |
| 278 |
|
private boolean transitionRunStateTo(int state) { |
| 279 |
|
for (;;) { |
| 280 |
|
int s = runState; |
| 281 |
|
if (s >= state) |
| 282 |
|
return false; |
| 283 |
< |
if (_unsafe.compareAndSwapInt(this, runStateOffset, s, state)) |
| 283 |
> |
if (UNSAFE.compareAndSwapInt(this, runStateOffset, s, state)) |
| 284 |
|
return true; |
| 285 |
|
} |
| 286 |
|
} |
| 287 |
|
|
| 288 |
|
/** |
| 289 |
< |
* Try to set status to active; fail on contention |
| 289 |
> |
* Tries to set status to active; fails on contention. |
| 290 |
|
*/ |
| 291 |
|
private boolean tryActivate() { |
| 292 |
|
if (!active) { |
| 298 |
|
} |
| 299 |
|
|
| 300 |
|
/** |
| 301 |
< |
* Try to set status to active; fail on contention |
| 301 |
> |
* Tries to set status to inactive; fails on contention. |
| 302 |
|
*/ |
| 303 |
|
private boolean tryInactivate() { |
| 304 |
|
if (active) { |
| 310 |
|
} |
| 311 |
|
|
| 312 |
|
/** |
| 313 |
< |
* Computes next value for random victim probe. Scans don't |
| 313 |
> |
* Computes next value for random victim probe. Scans don't |
| 314 |
|
* require a very high quality generator, but also not a crummy |
| 315 |
< |
* one. Marsaglia xor-shift is cheap and works well. |
| 315 |
> |
* one. Marsaglia xor-shift is cheap and works well. |
| 316 |
|
*/ |
| 317 |
|
private static int xorShift(int r) { |
| 318 |
< |
r ^= r << 1; |
| 319 |
< |
r ^= r >>> 3; |
| 320 |
< |
r ^= r << 10; |
| 297 |
< |
return r; |
| 318 |
> |
r ^= (r << 13); |
| 319 |
> |
r ^= (r >>> 17); |
| 320 |
> |
return r ^ (r << 5); |
| 321 |
|
} |
| 322 |
|
|
| 323 |
|
// Lifecycle methods |
| 341 |
|
} |
| 342 |
|
|
| 343 |
|
/** |
| 344 |
< |
* Execute tasks until shut down. |
| 344 |
> |
* Executes tasks until shut down. |
| 345 |
|
*/ |
| 346 |
|
private void mainLoop() { |
| 347 |
|
while (!isShutdown()) { |
| 348 |
|
ForkJoinTask<?> t = pollTask(); |
| 349 |
< |
if (t != null || (t = pollSubmission()) != null) |
| 349 |
> |
if (t != null || (t = pollSubmission()) != null) |
| 350 |
|
t.quietlyExec(); |
| 351 |
|
else if (tryInactivate()) |
| 352 |
|
pool.sync(this); |
| 373 |
|
} |
| 374 |
|
|
| 375 |
|
/** |
| 376 |
< |
* Perform cleanup associated with termination of this worker |
| 376 |
> |
* Performs cleanup associated with termination of this worker |
| 377 |
|
* thread. If you override this method, you must invoke |
| 378 |
< |
* super.onTermination at the end of the overridden method. |
| 378 |
> |
* {@code super.onTermination} at the end of the overridden method. |
| 379 |
|
* |
| 380 |
|
* @param exception the exception causing this thread to abort due |
| 381 |
< |
* to an unrecoverable error, or null if completed normally. |
| 381 |
> |
* to an unrecoverable error, or {@code null} if completed normally |
| 382 |
|
*/ |
| 383 |
|
protected void onTermination(Throwable exception) { |
| 384 |
|
// Execute remaining local tasks unless aborting or terminating |
| 387 |
|
ForkJoinTask<?> t = popTask(); |
| 388 |
|
if (t != null) |
| 389 |
|
t.quietlyExec(); |
| 390 |
< |
} catch(Throwable ex) { |
| 390 |
> |
} catch (Throwable ex) { |
| 391 |
|
exception = ex; |
| 392 |
|
} |
| 393 |
|
} |
| 394 |
|
// Cancel other tasks, transition status, notify pool, and |
| 395 |
|
// propagate exception to uncaught exception handler |
| 396 |
|
try { |
| 397 |
< |
do;while (!tryInactivate()); // ensure inactive |
| 398 |
< |
cancelTasks(); |
| 397 |
> |
do {} while (!tryInactivate()); // ensure inactive |
| 398 |
> |
cancelTasks(); |
| 399 |
|
runState = TERMINATED; |
| 400 |
|
pool.workerTerminated(this); |
| 401 |
|
} catch (Throwable ex) { // Shouldn't ever happen |
| 407 |
|
} |
| 408 |
|
} |
| 409 |
|
|
| 410 |
< |
// Intrinsics-based support for queue operations. |
| 410 |
> |
// Intrinsics-based support for queue operations. |
| 411 |
|
|
| 412 |
|
/** |
| 413 |
< |
* Add in store-order the given task at given slot of q to |
| 414 |
< |
* null. Caller must ensure q is nonnull and index is in range. |
| 413 |
> |
* Adds in store-order the given task at given slot of q to null. |
| 414 |
> |
* Caller must ensure q is non-null and index is in range. |
| 415 |
|
*/ |
| 416 |
|
private static void setSlot(ForkJoinTask<?>[] q, int i, |
| 417 |
< |
ForkJoinTask<?> t){ |
| 418 |
< |
_unsafe.putOrderedObject(q, (i << qShift) + qBase, t); |
| 417 |
> |
ForkJoinTask<?> t) { |
| 418 |
> |
UNSAFE.putOrderedObject(q, (i << qShift) + qBase, t); |
| 419 |
|
} |
| 420 |
|
|
| 421 |
|
/** |
| 422 |
< |
* CAS given slot of q to null. Caller must ensure q is nonnull |
| 422 |
> |
* CAS given slot of q to null. Caller must ensure q is non-null |
| 423 |
|
* and index is in range. |
| 424 |
|
*/ |
| 425 |
|
private static boolean casSlotNull(ForkJoinTask<?>[] q, int i, |
| 426 |
|
ForkJoinTask<?> t) { |
| 427 |
< |
return _unsafe.compareAndSwapObject(q, (i << qShift) + qBase, t, null); |
| 427 |
> |
return UNSAFE.compareAndSwapObject(q, (i << qShift) + qBase, t, null); |
| 428 |
|
} |
| 429 |
|
|
| 430 |
|
/** |
| 431 |
|
* Sets sp in store-order. |
| 432 |
|
*/ |
| 433 |
|
private void storeSp(int s) { |
| 434 |
< |
_unsafe.putOrderedInt(this, spOffset, s); |
| 434 |
> |
UNSAFE.putOrderedInt(this, spOffset, s); |
| 435 |
|
} |
| 436 |
|
|
| 437 |
|
// Main queue methods |
| 438 |
|
|
| 439 |
|
/** |
| 440 |
|
* Pushes a task. Called only by current thread. |
| 441 |
< |
* @param t the task. Caller must ensure nonnull |
| 441 |
> |
* |
| 442 |
> |
* @param t the task. Caller must ensure non-null. |
| 443 |
|
*/ |
| 444 |
|
final void pushTask(ForkJoinTask<?> t) { |
| 445 |
|
ForkJoinTask<?>[] q = queue; |
| 456 |
|
/** |
| 457 |
|
* Tries to take a task from the base of the queue, failing if |
| 458 |
|
* either empty or contended. |
| 459 |
< |
* @return a task, or null if none or contended. |
| 459 |
> |
* |
| 460 |
> |
* @return a task, or null if none or contended |
| 461 |
|
*/ |
| 462 |
< |
private ForkJoinTask<?> deqTask() { |
| 462 |
> |
final ForkJoinTask<?> deqTask() { |
| 463 |
|
ForkJoinTask<?> t; |
| 464 |
|
ForkJoinTask<?>[] q; |
| 465 |
|
int i; |
| 475 |
|
} |
| 476 |
|
|
| 477 |
|
/** |
| 478 |
+ |
* Tries to take a task from the base of own queue, activating if |
| 479 |
+ |
* necessary, failing only if empty. Called only by current thread. |
| 480 |
+ |
* |
| 481 |
+ |
* @return a task, or null if none |
| 482 |
+ |
*/ |
| 483 |
+ |
final ForkJoinTask<?> locallyDeqTask() { |
| 484 |
+ |
int b; |
| 485 |
+ |
while (sp != (b = base)) { |
| 486 |
+ |
if (tryActivate()) { |
| 487 |
+ |
ForkJoinTask<?>[] q = queue; |
| 488 |
+ |
int i = (q.length - 1) & b; |
| 489 |
+ |
ForkJoinTask<?> t = q[i]; |
| 490 |
+ |
if (t != null && casSlotNull(q, i, t)) { |
| 491 |
+ |
base = b + 1; |
| 492 |
+ |
return t; |
| 493 |
+ |
} |
| 494 |
+ |
} |
| 495 |
+ |
} |
| 496 |
+ |
return null; |
| 497 |
+ |
} |
| 498 |
+ |
|
| 499 |
+ |
/** |
| 500 |
|
* Returns a popped task, or null if empty. Ensures active status |
| 501 |
< |
* if nonnull. Called only by current thread. |
| 501 |
> |
* if non-null. Called only by current thread. |
| 502 |
|
*/ |
| 503 |
|
final ForkJoinTask<?> popTask() { |
| 504 |
|
int s = sp; |
| 521 |
|
* Specialized version of popTask to pop only if |
| 522 |
|
* topmost element is the given task. Called only |
| 523 |
|
* by current thread while active. |
| 524 |
< |
* @param t the task. Caller must ensure nonnull |
| 524 |
> |
* |
| 525 |
> |
* @param t the task. Caller must ensure non-null. |
| 526 |
|
*/ |
| 527 |
|
final boolean unpushTask(ForkJoinTask<?> t) { |
| 528 |
|
ForkJoinTask<?>[] q = queue; |
| 536 |
|
} |
| 537 |
|
|
| 538 |
|
/** |
| 539 |
< |
* Returns next task to pop. |
| 539 |
> |
* Returns next task or null if empty or contended |
| 540 |
|
*/ |
| 541 |
|
final ForkJoinTask<?> peekTask() { |
| 542 |
|
ForkJoinTask<?>[] q = queue; |
| 543 |
< |
return q == null? null : q[(sp - 1) & (q.length - 1)]; |
| 543 |
> |
if (q == null) |
| 544 |
> |
return null; |
| 545 |
> |
int mask = q.length - 1; |
| 546 |
> |
int i = locallyFifo ? base : (sp - 1); |
| 547 |
> |
return q[i & mask]; |
| 548 |
|
} |
| 549 |
|
|
| 550 |
|
/** |
| 606 |
|
ForkJoinWorkerThread v = ws[mask & idx]; |
| 607 |
|
if (v == null || v.sp == v.base) { |
| 608 |
|
if (probes <= mask) |
| 609 |
< |
idx = (probes++ < 0)? r : (idx + 1); |
| 609 |
> |
idx = (probes++ < 0) ? r : (idx + 1); |
| 610 |
|
else |
| 611 |
|
break; |
| 612 |
|
} |
| 622 |
|
} |
| 623 |
|
|
| 624 |
|
/** |
| 625 |
< |
* Pops or steals a task |
| 625 |
> |
* Gets and removes a local or stolen task. |
| 626 |
> |
* |
| 627 |
|
* @return a task, if available |
| 628 |
|
*/ |
| 629 |
|
final ForkJoinTask<?> pollTask() { |
| 630 |
< |
ForkJoinTask<?> t = popTask(); |
| 630 |
> |
ForkJoinTask<?> t = locallyFifo ? locallyDeqTask() : popTask(); |
| 631 |
|
if (t == null && (t = scan()) != null) |
| 632 |
|
++stealCount; |
| 633 |
|
return t; |
| 634 |
|
} |
| 635 |
|
|
| 636 |
|
/** |
| 637 |
+ |
* Gets a local task. |
| 638 |
+ |
* |
| 639 |
+ |
* @return a task, if available |
| 640 |
+ |
*/ |
| 641 |
+ |
final ForkJoinTask<?> pollLocalTask() { |
| 642 |
+ |
return locallyFifo ? locallyDeqTask() : popTask(); |
| 643 |
+ |
} |
| 644 |
+ |
|
| 645 |
+ |
/** |
| 646 |
|
* Returns a pool submission, if one exists, activating first. |
| 647 |
+ |
* |
| 648 |
|
* @return a submission, if available |
| 649 |
|
*/ |
| 650 |
|
private ForkJoinTask<?> pollSubmission() { |
| 670 |
|
} |
| 671 |
|
|
| 672 |
|
/** |
| 673 |
< |
* Get and clear steal count for accumulation by pool. Called |
| 673 |
> |
* Drains tasks to given collection c. |
| 674 |
> |
* |
| 675 |
> |
* @return the number of tasks drained |
| 676 |
> |
*/ |
| 677 |
> |
final int drainTasksTo(Collection<? super ForkJoinTask<?>> c) { |
| 678 |
> |
int n = 0; |
| 679 |
> |
ForkJoinTask<?> t; |
| 680 |
> |
while (base != sp && (t = deqTask()) != null) { |
| 681 |
> |
c.add(t); |
| 682 |
> |
++n; |
| 683 |
> |
} |
| 684 |
> |
return n; |
| 685 |
> |
} |
| 686 |
> |
|
| 687 |
> |
/** |
| 688 |
> |
* Gets and clears steal count for accumulation by pool. Called |
| 689 |
|
* only when known to be idle (in pool.sync and termination). |
| 690 |
|
*/ |
| 691 |
|
final int getAndClearStealCount() { |
| 695 |
|
} |
| 696 |
|
|
| 697 |
|
/** |
| 698 |
< |
* Returns true if at least one worker in the given array appears |
| 699 |
< |
* to have at least one queued task. |
| 698 |
> |
* Returns {@code true} if at least one worker in the given array |
| 699 |
> |
* appears to have at least one queued task. |
| 700 |
> |
* |
| 701 |
|
* @param ws array of workers |
| 702 |
|
*/ |
| 703 |
|
static boolean hasQueuedTasks(ForkJoinWorkerThread[] ws) { |
| 720 |
|
* Returns an estimate of the number of tasks in the queue. |
| 721 |
|
*/ |
| 722 |
|
final int getQueueSize() { |
| 723 |
< |
int n = sp - base; |
| 724 |
< |
return n < 0? 0 : n; // suppress momentarily negative values |
| 723 |
> |
// suppress momentarily negative values |
| 724 |
> |
return Math.max(0, sp - base); |
| 725 |
|
} |
| 726 |
|
|
| 727 |
|
/** |
| 734 |
|
} |
| 735 |
|
|
| 736 |
|
/** |
| 737 |
< |
* Scan, returning early if joinMe done |
| 737 |
> |
* Scans, returning early if joinMe done. |
| 738 |
|
*/ |
| 739 |
|
final ForkJoinTask<?> scanWhileJoining(ForkJoinTask<?> joinMe) { |
| 740 |
|
ForkJoinTask<?> t = pollTask(); |
| 744 |
|
} |
| 745 |
|
return t; |
| 746 |
|
} |
| 747 |
< |
|
| 747 |
> |
|
| 748 |
|
/** |
| 749 |
< |
* Runs tasks until pool isQuiescent |
| 749 |
> |
* Runs tasks until {@code pool.isQuiescent()}. |
| 750 |
|
*/ |
| 751 |
|
final void helpQuiescePool() { |
| 752 |
|
for (;;) { |
| 753 |
|
ForkJoinTask<?> t = pollTask(); |
| 754 |
< |
if (t != null) |
| 754 |
> |
if (t != null) |
| 755 |
|
t.quietlyExec(); |
| 756 |
|
else if (tryInactivate() && pool.isQuiescent()) |
| 757 |
|
break; |
| 758 |
|
} |
| 759 |
< |
do;while (!tryActivate()); // re-activate on exit |
| 759 |
> |
do {} while (!tryActivate()); // re-activate on exit |
| 760 |
|
} |
| 761 |
|
|
| 762 |
< |
// Temporary Unsafe mechanics for preliminary release |
| 762 |
> |
// Unsafe mechanics |
| 763 |
> |
|
| 764 |
> |
private static final sun.misc.Unsafe UNSAFE = getUnsafe(); |
| 765 |
> |
private static final long spOffset = |
| 766 |
> |
objectFieldOffset("sp", ForkJoinWorkerThread.class); |
| 767 |
> |
private static final long runStateOffset = |
| 768 |
> |
objectFieldOffset("runState", ForkJoinWorkerThread.class); |
| 769 |
> |
private static final long qBase; |
| 770 |
> |
private static final int qShift; |
| 771 |
|
|
| 685 |
– |
static final Unsafe _unsafe; |
| 686 |
– |
static final long baseOffset; |
| 687 |
– |
static final long spOffset; |
| 688 |
– |
static final long runStateOffset; |
| 689 |
– |
static final long qBase; |
| 690 |
– |
static final int qShift; |
| 772 |
|
static { |
| 773 |
+ |
qBase = UNSAFE.arrayBaseOffset(ForkJoinTask[].class); |
| 774 |
+ |
int s = UNSAFE.arrayIndexScale(ForkJoinTask[].class); |
| 775 |
+ |
if ((s & (s-1)) != 0) |
| 776 |
+ |
throw new Error("data type scale not a power of two"); |
| 777 |
+ |
qShift = 31 - Integer.numberOfLeadingZeros(s); |
| 778 |
+ |
} |
| 779 |
+ |
|
| 780 |
+ |
private static long objectFieldOffset(String field, Class<?> klazz) { |
| 781 |
+ |
try { |
| 782 |
+ |
return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field)); |
| 783 |
+ |
} catch (NoSuchFieldException e) { |
| 784 |
+ |
// Convert Exception to corresponding Error |
| 785 |
+ |
NoSuchFieldError error = new NoSuchFieldError(field); |
| 786 |
+ |
error.initCause(e); |
| 787 |
+ |
throw error; |
| 788 |
+ |
} |
| 789 |
+ |
} |
| 790 |
+ |
|
| 791 |
+ |
/** |
| 792 |
+ |
* Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package. |
| 793 |
+ |
* Replace with a simple call to Unsafe.getUnsafe when integrating |
| 794 |
+ |
* into a jdk. |
| 795 |
+ |
* |
| 796 |
+ |
* @return a sun.misc.Unsafe |
| 797 |
+ |
*/ |
| 798 |
+ |
private static sun.misc.Unsafe getUnsafe() { |
| 799 |
|
try { |
| 800 |
< |
if (ForkJoinWorkerThread.class.getClassLoader() != null) { |
| 801 |
< |
Field f = Unsafe.class.getDeclaredField("theUnsafe"); |
| 802 |
< |
f.setAccessible(true); |
| 803 |
< |
_unsafe = (Unsafe)f.get(null); |
| 800 |
> |
return sun.misc.Unsafe.getUnsafe(); |
| 801 |
> |
} catch (SecurityException se) { |
| 802 |
> |
try { |
| 803 |
> |
return java.security.AccessController.doPrivileged |
| 804 |
> |
(new java.security |
| 805 |
> |
.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
| 806 |
> |
public sun.misc.Unsafe run() throws Exception { |
| 807 |
> |
java.lang.reflect.Field f = sun.misc |
| 808 |
> |
.Unsafe.class.getDeclaredField("theUnsafe"); |
| 809 |
> |
f.setAccessible(true); |
| 810 |
> |
return (sun.misc.Unsafe) f.get(null); |
| 811 |
> |
}}); |
| 812 |
> |
} catch (java.security.PrivilegedActionException e) { |
| 813 |
> |
throw new RuntimeException("Could not initialize intrinsics", |
| 814 |
> |
e.getCause()); |
| 815 |
|
} |
| 698 |
– |
else |
| 699 |
– |
_unsafe = Unsafe.getUnsafe(); |
| 700 |
– |
baseOffset = _unsafe.objectFieldOffset |
| 701 |
– |
(ForkJoinWorkerThread.class.getDeclaredField("base")); |
| 702 |
– |
spOffset = _unsafe.objectFieldOffset |
| 703 |
– |
(ForkJoinWorkerThread.class.getDeclaredField("sp")); |
| 704 |
– |
runStateOffset = _unsafe.objectFieldOffset |
| 705 |
– |
(ForkJoinWorkerThread.class.getDeclaredField("runState")); |
| 706 |
– |
qBase = _unsafe.arrayBaseOffset(ForkJoinTask[].class); |
| 707 |
– |
int s = _unsafe.arrayIndexScale(ForkJoinTask[].class); |
| 708 |
– |
if ((s & (s-1)) != 0) |
| 709 |
– |
throw new Error("data type scale not a power of two"); |
| 710 |
– |
qShift = 31 - Integer.numberOfLeadingZeros(s); |
| 711 |
– |
} catch (Exception e) { |
| 712 |
– |
throw new RuntimeException("Could not initialize intrinsics", e); |
| 816 |
|
} |
| 817 |
|
} |
| 818 |
|
} |
