440 |
|
* Common Pool |
441 |
|
* =========== |
442 |
|
* |
443 |
< |
* The static commonPool always exists after static |
443 |
> |
* The static common Pool always exists after static |
444 |
|
* initialization. Since it (or any other created pool) need |
445 |
|
* never be used, we minimize initial construction overhead and |
446 |
|
* footprint to the setup of about a dozen fields, with no nested |
708 |
|
* shared-queue version is embedded in method externalPush.) |
709 |
|
* |
710 |
|
* @param task the task. Caller must ensure non-null. |
711 |
< |
* @throw RejectedExecutionException if array cannot be resized |
711 |
> |
* @throws RejectedExecutionException if array cannot be resized |
712 |
|
*/ |
713 |
|
final void push(ForkJoinTask<?> task) { |
714 |
|
ForkJoinTask<?>[] a; ForkJoinPool p; |
952 |
|
|
953 |
|
/** |
954 |
|
* Polls for and executes the given task or any other task in |
955 |
< |
* its CountedCompleter computation |
955 |
> |
* its CountedCompleter computation. |
956 |
|
*/ |
957 |
|
final boolean pollAndExecCC(ForkJoinTask<?> root) { |
958 |
|
ForkJoinTask<?>[] a; int b; Object o; |
1026 |
|
private static final int ABASE; |
1027 |
|
private static final int ASHIFT; |
1028 |
|
static { |
1029 |
– |
int s; |
1029 |
|
try { |
1030 |
|
U = getUnsafe(); |
1031 |
|
Class<?> k = WorkQueue.class; |
1033 |
|
QLOCK = U.objectFieldOffset |
1034 |
|
(k.getDeclaredField("qlock")); |
1035 |
|
ABASE = U.arrayBaseOffset(ak); |
1036 |
< |
s = U.arrayIndexScale(ak); |
1036 |
> |
int scale = U.arrayIndexScale(ak); |
1037 |
> |
if ((scale & (scale - 1)) != 0) |
1038 |
> |
throw new Error("data type scale not a power of two"); |
1039 |
> |
ASHIFT = 31 - Integer.numberOfLeadingZeros(scale); |
1040 |
|
} catch (Exception e) { |
1041 |
|
throw new Error(e); |
1042 |
|
} |
1041 |
– |
if ((s & (s-1)) != 0) |
1042 |
– |
throw new Error("data type scale not a power of two"); |
1043 |
– |
ASHIFT = 31 - Integer.numberOfLeadingZeros(s); |
1043 |
|
} |
1044 |
|
} |
1045 |
|
|
1073 |
|
* to paranoically avoid potential initialization circularities |
1074 |
|
* as well as to simplify generated code. |
1075 |
|
*/ |
1076 |
< |
static final ForkJoinPool commonPool; |
1076 |
> |
static final ForkJoinPool common; |
1077 |
|
|
1078 |
|
/** |
1079 |
< |
* Common pool parallelism. Must equal commonPool.parallelism. |
1079 |
> |
* Common pool parallelism. Must equal common.parallelism. |
1080 |
|
*/ |
1081 |
< |
static final int commonPoolParallelism; |
1081 |
> |
static final int commonParallelism; |
1082 |
|
|
1083 |
|
/** |
1084 |
|
* Sequence number for creating workerNamePrefix. |
1086 |
|
private static int poolNumberSequence; |
1087 |
|
|
1088 |
|
/** |
1089 |
< |
* Return the next sequence number. We don't expect this to |
1090 |
< |
* ever contend so use simple builtin sync. |
1089 |
> |
* Returns the next sequence number. We don't expect this to |
1090 |
> |
* ever contend, so use simple builtin sync. |
1091 |
|
*/ |
1092 |
|
private static final synchronized int nextPoolId() { |
1093 |
|
return ++poolNumberSequence; |
1244 |
|
volatile Object pad10, pad11, pad12, pad13, pad14, pad15, pad16, pad17; |
1245 |
|
volatile Object pad18, pad19, pad1a, pad1b; |
1246 |
|
|
1247 |
< |
/* |
1247 |
> |
/** |
1248 |
|
* Acquires the plock lock to protect worker array and related |
1249 |
|
* updates. This method is called only if an initial CAS on plock |
1250 |
< |
* fails. This acts as a spinLock for normal cases, but falls back |
1250 |
> |
* fails. This acts as a spinlock for normal cases, but falls back |
1251 |
|
* to builtin monitor to block when (rarely) needed. This would be |
1252 |
|
* a terrible idea for a highly contended lock, but works fine as |
1253 |
|
* a more conservative alternative to a pure spinlock. |
1660 |
|
* park awaiting signal, else lingering to help scan and signal. |
1661 |
|
* |
1662 |
|
* * If a non-empty queue discovered or left as a hint, |
1663 |
< |
* help wake up other workers before return |
1663 |
> |
* help wake up other workers before return. |
1664 |
|
* |
1665 |
|
* @param w the worker (via its WorkQueue) |
1666 |
|
* @return a task or null if none found |
1931 |
|
* @param task the task to join |
1932 |
|
* @param mode if shared, exit upon completing any task |
1933 |
|
* if all workers are active |
1935 |
– |
* |
1934 |
|
*/ |
1935 |
|
private int helpComplete(ForkJoinTask<?> task, int mode) { |
1936 |
|
WorkQueue[] ws; WorkQueue q; int m, n, s, u; |
2239 |
|
*/ |
2240 |
|
private boolean tryTerminate(boolean now, boolean enable) { |
2241 |
|
int ps; |
2242 |
< |
if (this == commonPool) // cannot shut down |
2242 |
> |
if (this == common) // cannot shut down |
2243 |
|
return false; |
2244 |
|
if ((ps = plock) >= 0) { // enable by setting plock |
2245 |
|
if (!enable) |
2330 |
|
static WorkQueue commonSubmitterQueue() { |
2331 |
|
ForkJoinPool p; WorkQueue[] ws; int m; Submitter z; |
2332 |
|
return ((z = submitters.get()) != null && |
2333 |
< |
(p = commonPool) != null && |
2333 |
> |
(p = common) != null && |
2334 |
|
(ws = p.workQueues) != null && |
2335 |
|
(m = ws.length - 1) >= 0) ? |
2336 |
|
ws[m & z.seed & SQMASK] : null; |
2344 |
|
ForkJoinTask<?>[] a; int m, s; |
2345 |
|
if (t != null && |
2346 |
|
(z = submitters.get()) != null && |
2347 |
< |
(p = commonPool) != null && |
2347 |
> |
(p = common) != null && |
2348 |
|
(ws = p.workQueues) != null && |
2349 |
|
(m = ws.length - 1) >= 0 && |
2350 |
|
(q = ws[m & z.seed & SQMASK]) != null && |
2421 |
|
ForkJoinTask<?>[] a; int m, s, n; |
2422 |
|
if (t != null && |
2423 |
|
(z = submitters.get()) != null && |
2424 |
< |
(p = commonPool) != null && |
2424 |
> |
(p = common) != null && |
2425 |
|
(ws = p.workQueues) != null && |
2426 |
|
(m = ws.length - 1) >= 0 && |
2427 |
|
(q = ws[m & z.seed & SQMASK]) != null && |
2450 |
|
} |
2451 |
|
} |
2452 |
|
|
2455 |
– |
/** |
2456 |
– |
* Restricted version of helpQuiescePool for external callers |
2457 |
– |
*/ |
2458 |
– |
static void externalHelpQuiescePool() { |
2459 |
– |
ForkJoinPool p; ForkJoinTask<?> t; WorkQueue q; int b; |
2460 |
– |
if ((p = commonPool) != null && |
2461 |
– |
(q = p.findNonEmptyStealQueue(1)) != null && |
2462 |
– |
(b = q.base) - q.top < 0 && |
2463 |
– |
(t = q.pollAt(b)) != null) { |
2464 |
– |
if (q.base - q.top < 0) |
2465 |
– |
p.signalWork(q); |
2466 |
– |
t.doExec(); |
2467 |
– |
} |
2468 |
– |
} |
2469 |
– |
|
2453 |
|
// Exported methods |
2454 |
|
|
2455 |
|
// Constructors |
2466 |
|
* java.lang.RuntimePermission}{@code ("modifyThread")} |
2467 |
|
*/ |
2468 |
|
public ForkJoinPool() { |
2469 |
< |
this(Runtime.getRuntime().availableProcessors(), |
2469 |
> |
this(Math.min(MAX_CAP, Runtime.getRuntime().availableProcessors()), |
2470 |
|
defaultForkJoinWorkerThreadFactory, null, false); |
2471 |
|
} |
2472 |
|
|
2549 |
|
|
2550 |
|
/** |
2551 |
|
* Returns the common pool instance. This pool is statically |
2552 |
< |
* constructed; its run state is unaffected by attempts to |
2553 |
< |
* {@link #shutdown} or {@link #shutdownNow}. |
2552 |
> |
* constructed; its run state is unaffected by attempts to {@link |
2553 |
> |
* #shutdown} or {@link #shutdownNow}. However this pool and any |
2554 |
> |
* ongoing processing are automatically terminated upon program |
2555 |
> |
* {@link System#exit}. Any program that relies on asynchronous |
2556 |
> |
* task processing to complete before program termination should |
2557 |
> |
* invoke {@code commonPool().}{@link #awaitQuiescence}, before |
2558 |
> |
* exit. |
2559 |
|
* |
2560 |
|
* @return the common pool instance |
2561 |
+ |
* @since 1.8 |
2562 |
|
*/ |
2563 |
|
public static ForkJoinPool commonPool() { |
2564 |
< |
// assert commonPool != null : "static init error"; |
2565 |
< |
return commonPool; |
2564 |
> |
// assert common != null : "static init error"; |
2565 |
> |
return common; |
2566 |
|
} |
2567 |
|
|
2568 |
|
// Execution methods |
2685 |
|
// In previous versions of this class, this method constructed |
2686 |
|
// a task to run ForkJoinTask.invokeAll, but now external |
2687 |
|
// invocation of multiple tasks is at least as efficient. |
2688 |
< |
List<ForkJoinTask<T>> fs = new ArrayList<ForkJoinTask<T>>(tasks.size()); |
2700 |
< |
// Workaround needed because method wasn't declared with |
2701 |
< |
// wildcards in return type but should have been. |
2702 |
< |
@SuppressWarnings({"unchecked", "rawtypes"}) |
2703 |
< |
List<Future<T>> futures = (List<Future<T>>) (List) fs; |
2688 |
> |
ArrayList<Future<T>> futures = new ArrayList<Future<T>>(tasks.size()); |
2689 |
|
|
2690 |
|
boolean done = false; |
2691 |
|
try { |
2692 |
|
for (Callable<T> t : tasks) { |
2693 |
|
ForkJoinTask<T> f = new ForkJoinTask.AdaptedCallable<T>(t); |
2694 |
+ |
futures.add(f); |
2695 |
|
externalPush(f); |
2710 |
– |
fs.add(f); |
2696 |
|
} |
2697 |
< |
for (ForkJoinTask<T> f : fs) |
2698 |
< |
f.quietlyJoin(); |
2697 |
> |
for (int i = 0, size = futures.size(); i < size; i++) |
2698 |
> |
((ForkJoinTask<?>)futures.get(i)).quietlyJoin(); |
2699 |
|
done = true; |
2700 |
|
return futures; |
2701 |
|
} finally { |
2702 |
|
if (!done) |
2703 |
< |
for (ForkJoinTask<T> f : fs) |
2704 |
< |
f.cancel(false); |
2703 |
> |
for (int i = 0, size = futures.size(); i < size; i++) |
2704 |
> |
futures.get(i).cancel(false); |
2705 |
|
} |
2706 |
|
} |
2707 |
|
|
2737 |
|
* Returns the targeted parallelism level of the common pool. |
2738 |
|
* |
2739 |
|
* @return the targeted parallelism level of the common pool |
2740 |
+ |
* @since 1.8 |
2741 |
|
*/ |
2742 |
|
public static int getCommonPoolParallelism() { |
2743 |
< |
return commonPoolParallelism; |
2743 |
> |
return commonParallelism; |
2744 |
|
} |
2745 |
|
|
2746 |
|
/** |
2998 |
|
* Possibly initiates an orderly shutdown in which previously |
2999 |
|
* submitted tasks are executed, but no new tasks will be |
3000 |
|
* accepted. Invocation has no effect on execution state if this |
3001 |
< |
* is the {@link #commonPool}, and no additional effect if |
3001 |
> |
* is the {@link #commonPool()}, and no additional effect if |
3002 |
|
* already shut down. Tasks that are in the process of being |
3003 |
|
* submitted concurrently during the course of this method may or |
3004 |
|
* may not be rejected. |
3016 |
|
/** |
3017 |
|
* Possibly attempts to cancel and/or stop all tasks, and reject |
3018 |
|
* all subsequently submitted tasks. Invocation has no effect on |
3019 |
< |
* execution state if this is the {@link #commonPool}, and no |
3019 |
> |
* execution state if this is the {@link #commonPool()}, and no |
3020 |
|
* additional effect if already shut down. Otherwise, tasks that |
3021 |
|
* are in the process of being submitted or executed concurrently |
3022 |
|
* during the course of this method may or may not be |
3079 |
|
/** |
3080 |
|
* Blocks until all tasks have completed execution after a |
3081 |
|
* shutdown request, or the timeout occurs, or the current thread |
3082 |
< |
* is interrupted, whichever happens first. Note that the {@link |
3083 |
< |
* #commonPool()} never terminates until program shutdown so |
3084 |
< |
* this method will always time out. |
3082 |
> |
* is interrupted, whichever happens first. Because the {@link |
3083 |
> |
* #commonPool()} never terminates until program shutdown, when |
3084 |
> |
* applied to the common pool, this method is equivalent to {@link |
3085 |
> |
* #awaitQuiescence} but always returns {@code false}. |
3086 |
|
* |
3087 |
|
* @param timeout the maximum time to wait |
3088 |
|
* @param unit the time unit of the timeout argument |
3092 |
|
*/ |
3093 |
|
public boolean awaitTermination(long timeout, TimeUnit unit) |
3094 |
|
throws InterruptedException { |
3095 |
+ |
if (Thread.interrupted()) |
3096 |
+ |
throw new InterruptedException(); |
3097 |
+ |
if (this == common) { |
3098 |
+ |
awaitQuiescence(timeout, unit); |
3099 |
+ |
return false; |
3100 |
+ |
} |
3101 |
|
long nanos = unit.toNanos(timeout); |
3102 |
|
if (isTerminated()) |
3103 |
|
return true; |
3117 |
|
} |
3118 |
|
|
3119 |
|
/** |
3120 |
+ |
* If called by a ForkJoinTask operating in this pool, equivalent |
3121 |
+ |
* in effect to {@link ForkJoinTask#helpQuiesce}. Otherwise, |
3122 |
+ |
* waits and/or attempts to assist performing tasks until this |
3123 |
+ |
* pool {@link #isQuiescent} or the indicated timeout elapses. |
3124 |
+ |
* |
3125 |
+ |
* @param timeout the maximum time to wait |
3126 |
+ |
* @param unit the time unit of the timeout argument |
3127 |
+ |
* @return {@code true} if quiescent; {@code false} if the |
3128 |
+ |
* timeout elapsed. |
3129 |
+ |
*/ |
3130 |
+ |
public boolean awaitQuiescence(long timeout, TimeUnit unit) { |
3131 |
+ |
long nanos = unit.toNanos(timeout); |
3132 |
+ |
ForkJoinWorkerThread wt; |
3133 |
+ |
Thread thread = Thread.currentThread(); |
3134 |
+ |
if ((thread instanceof ForkJoinWorkerThread) && |
3135 |
+ |
(wt = (ForkJoinWorkerThread)thread).pool == this) { |
3136 |
+ |
helpQuiescePool(wt.workQueue); |
3137 |
+ |
return true; |
3138 |
+ |
} |
3139 |
+ |
long startTime = System.nanoTime(); |
3140 |
+ |
WorkQueue[] ws; |
3141 |
+ |
int r = 0, m; |
3142 |
+ |
boolean found = true; |
3143 |
+ |
while (!isQuiescent() && (ws = workQueues) != null && |
3144 |
+ |
(m = ws.length - 1) >= 0) { |
3145 |
+ |
if (!found) { |
3146 |
+ |
if ((System.nanoTime() - startTime) > nanos) |
3147 |
+ |
return false; |
3148 |
+ |
Thread.yield(); // cannot block |
3149 |
+ |
} |
3150 |
+ |
found = false; |
3151 |
+ |
for (int j = (m + 1) << 2; j >= 0; --j) { |
3152 |
+ |
ForkJoinTask<?> t; WorkQueue q; int b; |
3153 |
+ |
if ((q = ws[r++ & m]) != null && (b = q.base) - q.top < 0) { |
3154 |
+ |
found = true; |
3155 |
+ |
if ((t = q.pollAt(b)) != null) { |
3156 |
+ |
if (q.base - q.top < 0) |
3157 |
+ |
signalWork(q); |
3158 |
+ |
t.doExec(); |
3159 |
+ |
} |
3160 |
+ |
break; |
3161 |
+ |
} |
3162 |
+ |
} |
3163 |
+ |
} |
3164 |
+ |
return true; |
3165 |
+ |
} |
3166 |
+ |
|
3167 |
+ |
/** |
3168 |
+ |
* Waits and/or attempts to assist performing tasks indefinitely |
3169 |
+ |
* until the {@link #commonPool()} {@link #isQuiescent} |
3170 |
+ |
*/ |
3171 |
+ |
static void quiesceCommonPool() { |
3172 |
+ |
common.awaitQuiescence(Long.MAX_VALUE, TimeUnit.NANOSECONDS); |
3173 |
+ |
} |
3174 |
+ |
|
3175 |
+ |
/** |
3176 |
|
* Interface for extending managed parallelism for tasks running |
3177 |
|
* in {@link ForkJoinPool}s. |
3178 |
|
* |
3325 |
|
private static final long QLOCK; |
3326 |
|
|
3327 |
|
static { |
3328 |
< |
int s; // initialize field offsets for CAS etc |
3328 |
> |
// initialize field offsets for CAS etc |
3329 |
|
try { |
3330 |
|
U = getUnsafe(); |
3331 |
|
Class<?> k = ForkJoinPool.class; |
3345 |
|
(wk.getDeclaredField("qlock")); |
3346 |
|
Class<?> ak = ForkJoinTask[].class; |
3347 |
|
ABASE = U.arrayBaseOffset(ak); |
3348 |
< |
s = U.arrayIndexScale(ak); |
3349 |
< |
ASHIFT = 31 - Integer.numberOfLeadingZeros(s); |
3348 |
> |
int scale = U.arrayIndexScale(ak); |
3349 |
> |
if ((scale & (scale - 1)) != 0) |
3350 |
> |
throw new Error("data type scale not a power of two"); |
3351 |
> |
ASHIFT = 31 - Integer.numberOfLeadingZeros(scale); |
3352 |
|
} catch (Exception e) { |
3353 |
|
throw new Error(e); |
3354 |
|
} |
3304 |
– |
if ((s & (s-1)) != 0) |
3305 |
– |
throw new Error("data type scale not a power of two"); |
3355 |
|
|
3356 |
|
submitters = new ThreadLocal<Submitter>(); |
3357 |
|
ForkJoinWorkerThreadFactory fac = defaultForkJoinWorkerThreadFactory = |
3388 |
|
par = Runtime.getRuntime().availableProcessors(); |
3389 |
|
if (par > MAX_CAP) |
3390 |
|
par = MAX_CAP; |
3391 |
< |
commonPoolParallelism = par; |
3391 |
> |
commonParallelism = par; |
3392 |
|
long np = (long)(-par); // precompute initial ctl value |
3393 |
|
long ct = ((np << AC_SHIFT) & AC_MASK) | ((np << TC_SHIFT) & TC_MASK); |
3394 |
|
|
3395 |
< |
commonPool = new ForkJoinPool(par, ct, fac, handler); |
3395 |
> |
common = new ForkJoinPool(par, ct, fac, handler); |
3396 |
|
} |
3397 |
|
|
3349 |
– |
|
3398 |
|
/** |
3399 |
|
* Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package. |
3400 |
|
* Replace with a simple call to Unsafe.getUnsafe when integrating |
3405 |
|
private static sun.misc.Unsafe getUnsafe() { |
3406 |
|
try { |
3407 |
|
return sun.misc.Unsafe.getUnsafe(); |
3408 |
< |
} catch (SecurityException se) { |
3409 |
< |
try { |
3410 |
< |
return java.security.AccessController.doPrivileged |
3411 |
< |
(new java.security |
3412 |
< |
.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
3413 |
< |
public sun.misc.Unsafe run() throws Exception { |
3414 |
< |
java.lang.reflect.Field f = sun.misc |
3415 |
< |
.Unsafe.class.getDeclaredField("theUnsafe"); |
3416 |
< |
f.setAccessible(true); |
3417 |
< |
return (sun.misc.Unsafe) f.get(null); |
3418 |
< |
}}); |
3419 |
< |
} catch (java.security.PrivilegedActionException e) { |
3420 |
< |
throw new RuntimeException("Could not initialize intrinsics", |
3421 |
< |
e.getCause()); |
3422 |
< |
} |
3408 |
> |
} catch (SecurityException tryReflectionInstead) {} |
3409 |
> |
try { |
3410 |
> |
return java.security.AccessController.doPrivileged |
3411 |
> |
(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
3412 |
> |
public sun.misc.Unsafe run() throws Exception { |
3413 |
> |
Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class; |
3414 |
> |
for (java.lang.reflect.Field f : k.getDeclaredFields()) { |
3415 |
> |
f.setAccessible(true); |
3416 |
> |
Object x = f.get(null); |
3417 |
> |
if (k.isInstance(x)) |
3418 |
> |
return k.cast(x); |
3419 |
> |
} |
3420 |
> |
throw new NoSuchFieldError("the Unsafe"); |
3421 |
> |
}}); |
3422 |
> |
} catch (java.security.PrivilegedActionException e) { |
3423 |
> |
throw new RuntimeException("Could not initialize intrinsics", |
3424 |
> |
e.getCause()); |
3425 |
|
} |
3426 |
|
} |
3377 |
– |
|
3427 |
|
} |