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root/jsr166/jsr166/src/jsr166y/ForkJoinPool.java
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Comparing jsr166/src/jsr166y/ForkJoinPool.java (file contents):
Revision 1.170 by dl, Wed Jan 2 14:10:43 2013 UTC vs.
Revision 1.188 by jsr166, Mon Jul 27 03:12:26 2015 UTC

# Line 687 | Line 687 | public class ForkJoinPool extends Abstra
687              return (n >= 0) ? 0 : -n; // ignore transient negative
688          }
689  
690 <       /**
690 >        /**
691           * Provides a more accurate estimate of whether this queue has
692           * any tasks than does queueSize, by checking whether a
693           * near-empty queue has at least one unclaimed task.
# Line 708 | Line 708 | public class ForkJoinPool extends Abstra
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;
# Line 725 | Line 725 | public class ForkJoinPool extends Abstra
725              }
726          }
727  
728 <       /**
728 >        /**
729           * Initializes or doubles the capacity of array. Call either
730           * by owner or with lock held -- it is OK for base, but not
731           * top, to move while resizings are in progress.
# Line 907 | Line 907 | public class ForkJoinPool extends Abstra
907           * or any other cancelled task. Returns (true) on any CAS
908           * or consistency check failure so caller can retry.
909           *
910 <         * @return false if no progress can be made, else true;
910 >         * @return false if no progress can be made, else true
911           */
912          final boolean tryRemoveAndExec(ForkJoinTask<?> task) {
913              boolean stat = true, removed = false, empty = true;
# Line 952 | Line 952 | public class ForkJoinPool extends Abstra
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;
# Line 1026 | Line 1026 | public class ForkJoinPool extends Abstra
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;
# Line 1034 | Line 1033 | public class ForkJoinPool extends Abstra
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  
# Line 1132 | Line 1131 | public class ForkJoinPool extends Abstra
1131       */
1132      private static final int SEED_INCREMENT = 0x61c88647;
1133  
1134 <    /**
1134 >    /*
1135       * Bits and masks for control variables
1136       *
1137       * Field ctl is a long packed with:
# Line 1245 | Line 1244 | public class ForkJoinPool extends Abstra
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.
# Line 2128 | Line 2127 | public class ForkJoinPool extends Abstra
2127                      w.runSubtask(t);
2128                  }
2129              }
2130 <            else if (active) {       // decrement active count without queuing
2130 >            else if (active) {      // decrement active count without queuing
2131                  long nc = (c = ctl) - AC_UNIT;
2132                  if ((int)(nc >> AC_SHIFT) + (config & SMASK) == 0)
2133 <                    return;          // bypass decrement-then-increment
2133 >                    return;         // bypass decrement-then-increment
2134                  if (U.compareAndSwapLong(this, CTL, c, nc))
2135                      active = false;
2136              }
# Line 2186 | Line 2185 | public class ForkJoinPool extends Abstra
2185       * producing extra tasks amortizes the uncertainty of progress and
2186       * diffusion assumptions.
2187       *
2188 <     * So, users will want to use values larger, but not much larger
2188 >     * So, users will want to use values larger (but not much larger)
2189       * than 1 to both smooth over transient shortages and hedge
2190       * against uneven progress; as traded off against the cost of
2191       * extra task overhead. We leave the user to pick a threshold
# Line 2467 | Line 2466 | public class ForkJoinPool extends Abstra
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  
# Line 2559 | Line 2558 | public class ForkJoinPool extends Abstra
2558       * exit.
2559       *
2560       * @return the common pool instance
2561 +     * @since 1.8
2562       */
2563      public static ForkJoinPool commonPool() {
2564          // assert common != null : "static init error";
# Line 2685 | Line 2685 | public class ForkJoinPool extends Abstra
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());
2689 <        // Workaround needed because method wasn't declared with
2690 <        // wildcards in return type but should have been.
2691 <        @SuppressWarnings({"unchecked", "rawtypes"})
2692 <            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);
2699 –                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  
# Line 2741 | Line 2737 | public class ForkJoinPool extends Abstra
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 commonParallelism;
# Line 3001 | Line 2998 | public class ForkJoinPool extends Abstra
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.
# Line 3019 | Line 3016 | public class ForkJoinPool extends Abstra
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
# Line 3169 | Line 3166 | public class ForkJoinPool extends Abstra
3166  
3167      /**
3168       * Waits and/or attempts to assist performing tasks indefinitely
3169 <     * until the {@link #commonPool()} {@link #isQuiescent}
3169 >     * until the {@link #commonPool()} {@link #isQuiescent}.
3170       */
3171      static void quiesceCommonPool() {
3172          common.awaitQuiescence(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
# Line 3328 | Line 3325 | public class ForkJoinPool extends Abstra
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;
# Line 3348 | Line 3345 | public class ForkJoinPool extends Abstra
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          }
3356 –        if ((s & (s-1)) != 0)
3357 –            throw new Error("data type scale not a power of two");
3355  
3356          submitters = new ThreadLocal<Submitter>();
3357          ForkJoinWorkerThreadFactory fac = defaultForkJoinWorkerThreadFactory =
# Line 3408 | Line 3405 | public class ForkJoinPool extends Abstra
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      }
3428 –
3427   }

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