7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011

Reviewed-by: dholmes, chegar, mduigou

src/share/classes/java/util/Collections.java

@@ -1452,10 +1452,10 @@ public class Collections {
              * when o is a Map.Entry, and calls o.setValue.
              */
             public boolean containsAll(Collection<?> coll) {
-                Iterator<?> it = coll.iterator();
-                while (it.hasNext())
-                    if (!contains(it.next())) // Invokes safe contains() above
+                for (Object e : coll) {
+                    if (!contains(e)) // Invokes safe contains() above
                         return false;
+                }
                 return true;
             }
             public boolean equals(Object o) {

src/share/classes/java/util/LinkedList.java

@@ -26,9 +26,9 @@
 package java.util;
 
 /**
- * Linked list implementation of the {@link List} and {@link Deque} interfaces.
- * Implements all optional operations, and permits all elements (including
- * {@code null}).
+ * Doubly-linked list implementation of the {@code List} and {@code Deque}
+ * interfaces.  Implements all optional list operations, and permits all
+ * elements (including {@code null}).
  *
  * <p>All of the operations perform as could be expected for a doubly-linked
  * list.  Operations that index into the list will traverse the list from

src/share/classes/java/util/concurrent/ConcurrentLinkedDeque.java

@@ -869,6 +869,8 @@ public class ConcurrentLinkedDeque<E>
 
     /**
      * Inserts the specified element at the front of this deque.
+     * As the deque is unbounded, this method will never throw
+     * {@link IllegalStateException}.
      *
      * @throws NullPointerException if the specified element is null
      */
@@ -878,6 +880,8 @@ public class ConcurrentLinkedDeque<E>
 
     /**
      * Inserts the specified element at the end of this deque.
+     * As the deque is unbounded, this method will never throw
+     * {@link IllegalStateException}.
      *
      * <p>This method is equivalent to {@link #add}.
      *
@@ -889,8 +893,9 @@ public class ConcurrentLinkedDeque<E>
 
     /**
      * Inserts the specified element at the front of this deque.
+     * As the deque is unbounded, this method will never return {@code false}.
      *
-     * @return {@code true} always
+     * @return {@code true} (as specified by {@link Deque#offerFirst})
      * @throws NullPointerException if the specified element is null
      */
     public boolean offerFirst(E e) {
@@ -900,10 +905,11 @@ public class ConcurrentLinkedDeque<E>
 
     /**
      * Inserts the specified element at the end of this deque.
+     * As the deque is unbounded, this method will never return {@code false}.
      *
      * <p>This method is equivalent to {@link #add}.
      *
-     * @return {@code true} always
+     * @return {@code true} (as specified by {@link Deque#offerLast})
      * @throws NullPointerException if the specified element is null
      */
     public boolean offerLast(E e) {
@@ -983,6 +989,7 @@ public class ConcurrentLinkedDeque<E>
 
     /**
      * Inserts the specified element at the tail of this deque.
+     * As the deque is unbounded, this method will never return {@code false}.
      *
      * @return {@code true} (as specified by {@link Queue#offer})
      * @throws NullPointerException if the specified element is null
@@ -993,6 +1000,8 @@ public class ConcurrentLinkedDeque<E>
 
     /**
      * Inserts the specified element at the tail of this deque.
+     * As the deque is unbounded, this method will never throw
+     * {@link IllegalStateException} or return {@code false}.
      *
      * @return {@code true} (as specified by {@link Collection#add})
      * @throws NullPointerException if the specified element is null

src/share/classes/java/util/concurrent/ConcurrentLinkedQueue.java

@@ -269,6 +269,8 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
 
     /**
      * Inserts the specified element at the tail of this queue.
+     * As the queue is unbounded, this method will never throw
+     * {@link IllegalStateException} or return {@code false}.
      *
      * @return {@code true} (as specified by {@link Collection#add})
      * @throws NullPointerException if the specified element is null
@@ -298,6 +300,7 @@ public class ConcurrentLinkedQueue<E> extends AbstractQueue<E>
 
     /**
      * Inserts the specified element at the tail of this queue.
+     * As the queue is unbounded, this method will never return {@code false}.
      *
      * @return {@code true} (as specified by {@link Queue#offer})
      * @throws NullPointerException if the specified element is null

src/share/classes/java/util/concurrent/ConcurrentSkipListMap.java

@@ -374,17 +374,11 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
                                   null, null, 1);
     }
 
-    /** Updater for casHead */
-    private static final
-        AtomicReferenceFieldUpdater<ConcurrentSkipListMap, HeadIndex>
-        headUpdater = AtomicReferenceFieldUpdater.newUpdater
-        (ConcurrentSkipListMap.class, HeadIndex.class, "head");
-
     /**
      * compareAndSet head node
      */
     private boolean casHead(HeadIndex<K,V> cmp, HeadIndex<K,V> val) {
-        return headUpdater.compareAndSet(this, cmp, val);
+        return UNSAFE.compareAndSwapObject(this, headOffset, cmp, val);
     }
 
     /* ---------------- Nodes -------------- */
@@ -423,28 +417,18 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
             this.next = next;
         }
 
-        /** Updater for casNext */
-        static final AtomicReferenceFieldUpdater<Node, Node>
-            nextUpdater = AtomicReferenceFieldUpdater.newUpdater
-            (Node.class, Node.class, "next");
-
-        /** Updater for casValue */
-        static final AtomicReferenceFieldUpdater<Node, Object>
-            valueUpdater = AtomicReferenceFieldUpdater.newUpdater
-            (Node.class, Object.class, "value");
-
         /**
          * compareAndSet value field
          */
         boolean casValue(Object cmp, Object val) {
-            return valueUpdater.compareAndSet(this, cmp, val);
+            return UNSAFE.compareAndSwapObject(this, valueOffset, cmp, val);
         }
 
         /**
          * compareAndSet next field
          */
         boolean casNext(Node<K,V> cmp, Node<K,V> val) {
-            return nextUpdater.compareAndSet(this, cmp, val);
+            return UNSAFE.compareAndSwapObject(this, nextOffset, cmp, val);
         }
 
         /**
@@ -522,6 +506,14 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
                 return null;
             return new AbstractMap.SimpleImmutableEntry<K,V>(key, v);
         }
+
+        // Unsafe mechanics
+        private static final sun.misc.Unsafe UNSAFE = sun.misc.Unsafe.getUnsafe();
+        private static final long valueOffset =
+            objectFieldOffset(UNSAFE, "value", Node.class);
+        private static final long nextOffset =
+            objectFieldOffset(UNSAFE, "next", Node.class);
+
     }
 
     /* ---------------- Indexing -------------- */
@@ -547,16 +539,11 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
             this.right = right;
         }
 
-        /** Updater for casRight */
-        static final AtomicReferenceFieldUpdater<Index, Index>
-            rightUpdater = AtomicReferenceFieldUpdater.newUpdater
-            (Index.class, Index.class, "right");
-
         /**
          * compareAndSet right field
          */
         final boolean casRight(Index<K,V> cmp, Index<K,V> val) {
-            return rightUpdater.compareAndSet(this, cmp, val);
+            return UNSAFE.compareAndSwapObject(this, rightOffset, cmp, val);
         }
 
         /**
@@ -591,6 +578,12 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
         final boolean unlink(Index<K,V> succ) {
             return !indexesDeletedNode() && casRight(succ, succ.right);
         }
+
+        // Unsafe mechanics
+        private static final sun.misc.Unsafe UNSAFE = sun.misc.Unsafe.getUnsafe();
+        private static final long rightOffset =
+            objectFieldOffset(UNSAFE, "right", Index.class);
+
     }
 
     /* ---------------- Head nodes -------------- */
@@ -640,7 +633,8 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
      * cast key as Comparable, which may cause ClassCastException,
      * which is propagated back to caller.
      */
-    private Comparable<? super K> comparable(Object key) throws ClassCastException {
+    private Comparable<? super K> comparable(Object key)
+            throws ClassCastException {
         if (key == null)
             throw new NullPointerException();
         if (comparator != null)
@@ -799,68 +793,12 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
     }
 
     /**
-     * Specialized variant of findNode to perform Map.get. Does a weak
-     * traversal, not bothering to fix any deleted index nodes,
-     * returning early if it happens to see key in index, and passing
-     * over any deleted base nodes, falling back to getUsingFindNode
-     * only if it would otherwise return value from an ongoing
-     * deletion. Also uses "bound" to eliminate need for some
-     * comparisons (see Pugh Cookbook). Also folds uses of null checks
-     * and node-skipping because markers have null keys.
+     * Gets value for key using findNode.
      * @param okey the key
      * @return the value, or null if absent
      */
     private V doGet(Object okey) {
         Comparable<? super K> key = comparable(okey);
-        Node<K,V> bound = null;
-        Index<K,V> q = head;
-        Index<K,V> r = q.right;
-        Node<K,V> n;
-        K k;
-        int c;
-        for (;;) {
-            Index<K,V> d;
-            // Traverse rights
-            if (r != null && (n = r.node) != bound && (k = n.key) != null) {
-                if ((c = key.compareTo(k)) > 0) {
-                    q = r;
-                    r = r.right;
-                    continue;
-                } else if (c == 0) {
-                    Object v = n.value;
-                    return (v != null)? (V)v : getUsingFindNode(key);
-                } else
-                    bound = n;
-            }
-
-            // Traverse down
-            if ((d = q.down) != null) {
-                q = d;
-                r = d.right;
-            } else
-                break;
-        }
-
-        // Traverse nexts
-        for (n = q.node.next;  n != null; n = n.next) {
-            if ((k = n.key) != null) {
-                if ((c = key.compareTo(k)) == 0) {
-                    Object v = n.value;
-                    return (v != null)? (V)v : getUsingFindNode(key);
-                } else if (c < 0)
-                    break;
-            }
-        }
-        return null;
-    }
-
-    /**
-     * Performs map.get via findNode.  Used as a backup if doGet
-     * encounters an in-progress deletion.
-     * @param key the key
-     * @return the value, or null if absent
-     */
-    private V getUsingFindNode(Comparable<? super K> key) {
         /*
          * Loop needed here and elsewhere in case value field goes
          * null just as it is about to be returned, in which case we
@@ -943,7 +881,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
         x ^= x << 13;
         x ^= x >>> 17;
         randomSeed = x ^= x << 5;
-        if ((x & 0x8001) != 0) // test highest and lowest bits
+        if ((x & 0x80000001) != 0) // test highest and lowest bits
             return 0;
         int level = 1;
         while (((x >>>= 1) & 1) != 0) ++level;
@@ -1256,7 +1194,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
                 Node<K,V> n = b.next;
                 for (;;) {
                     if (n == null)
-                        return (b.isBaseHeader())? null : b;
+                        return b.isBaseHeader() ? null : b;
                     Node<K,V> f = n.next;            // inconsistent read
                     if (n != b.next)
                         break;
@@ -1374,7 +1312,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
             Node<K,V> n = b.next;
             for (;;) {
                 if (n == null)
-                    return ((rel & LT) == 0 || b.isBaseHeader())? null : b;
+                    return ((rel & LT) == 0 || b.isBaseHeader()) ? null : b;
                 Node<K,V> f = n.next;
                 if (n != b.next)                  // inconsistent read
                     break;
@@ -1390,7 +1328,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
                     (c <  0 && (rel & LT) == 0))
                     return n;
                 if ( c <= 0 && (rel & LT) != 0)
-                    return (b.isBaseHeader())? null : b;
+                    return b.isBaseHeader() ? null : b;
                 b = n;
                 n = f;
             }
@@ -1744,7 +1682,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
             if (n.getValidValue() != null)
                 ++count;
         }
-        return (count >= Integer.MAX_VALUE)? Integer.MAX_VALUE : (int)count;
+        return (count >= Integer.MAX_VALUE) ? Integer.MAX_VALUE : (int) count;
     }
 
     /**
@@ -2099,7 +2037,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
      */
     public K lowerKey(K key) {
         Node<K,V> n = findNear(key, LT);
-        return (n == null)? null : n.key;
+        return (n == null) ? null : n.key;
     }
 
     /**
@@ -2123,7 +2061,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
      */
     public K floorKey(K key) {
         Node<K,V> n = findNear(key, LT|EQ);
-        return (n == null)? null : n.key;
+        return (n == null) ? null : n.key;
     }
 
     /**
@@ -2145,7 +2083,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
      */
     public K ceilingKey(K key) {
         Node<K,V> n = findNear(key, GT|EQ);
-        return (n == null)? null : n.key;
+        return (n == null) ? null : n.key;
     }
 
     /**
@@ -2169,7 +2107,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
      */
     public K higherKey(K key) {
         Node<K,V> n = findNear(key, GT);
-        return (n == null)? null : n.key;
+        return (n == null) ? null : n.key;
     }
 
     /**
@@ -2342,7 +2280,8 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
         return list;
     }
 
-    static final class KeySet<E> extends AbstractSet<E> implements NavigableSet<E> {
+    static final class KeySet<E>
+            extends AbstractSet<E> implements NavigableSet<E> {
         private final ConcurrentNavigableMap<E,Object> m;
         KeySet(ConcurrentNavigableMap<E,Object> map) { m = map; }
         public int size() { return m.size(); }
@@ -2359,11 +2298,11 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
         public E last() { return m.lastKey(); }
         public E pollFirst() {
             Map.Entry<E,Object> e = m.pollFirstEntry();
-            return e == null? null : e.getKey();
+            return (e == null) ? null : e.getKey();
         }
         public E pollLast() {
             Map.Entry<E,Object> e = m.pollLastEntry();
-            return e == null? null : e.getKey();
+            return (e == null) ? null : e.getKey();
         }
         public Iterator<E> iterator() {
             if (m instanceof ConcurrentSkipListMap)
@@ -2710,9 +2649,9 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
                     rel &= ~m.LT;
             }
             if (tooLow(key))
-                return ((rel & m.LT) != 0)? null : lowestEntry();
+                return ((rel & m.LT) != 0) ? null : lowestEntry();
             if (tooHigh(key))
-                return ((rel & m.LT) != 0)? highestEntry() : null;
+                return ((rel & m.LT) != 0) ? highestEntry() : null;
             for (;;) {
                 Node<K,V> n = m.findNear(key, rel);
                 if (n == null || !inBounds(n.key))
@@ -2783,7 +2722,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
 
         public V remove(Object key) {
             K k = (K)key;
-            return (!inBounds(k))? null : m.remove(k);
+            return (!inBounds(k)) ? null : m.remove(k);
         }
 
         public int size() {
@@ -2794,7 +2733,7 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
                 if (n.getValidValue() != null)
                     ++count;
             }
-            return count >= Integer.MAX_VALUE? Integer.MAX_VALUE : (int)count;
+            return count >= Integer.MAX_VALUE ? Integer.MAX_VALUE : (int)count;
         }
 
         public boolean isEmpty() {
@@ -2972,27 +2911,27 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
         }
 
         public K firstKey() {
-            return isDescending? highestKey() : lowestKey();
+            return isDescending ? highestKey() : lowestKey();
         }
 
         public K lastKey() {
-            return isDescending? lowestKey() : highestKey();
+            return isDescending ? lowestKey() : highestKey();
         }
 
         public Map.Entry<K,V> firstEntry() {
-            return isDescending? highestEntry() : lowestEntry();
+            return isDescending ? highestEntry() : lowestEntry();
         }
 
         public Map.Entry<K,V> lastEntry() {
-            return isDescending? lowestEntry() : highestEntry();
+            return isDescending ? lowestEntry() : highestEntry();
         }
 
         public Map.Entry<K,V> pollFirstEntry() {
-            return isDescending? removeHighest() : removeLowest();
+            return isDescending ? removeHighest() : removeLowest();
         }
 
         public Map.Entry<K,V> pollLastEntry() {
-            return isDescending? removeLowest() : removeHighest();
+            return isDescending ? removeLowest() : removeHighest();
         }
 
         /* ---------------- Submap Views -------------- */
@@ -3141,4 +3080,22 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
             }
         }
     }
+
+    // Unsafe mechanics
+    private static final sun.misc.Unsafe UNSAFE = sun.misc.Unsafe.getUnsafe();
+    private static final long headOffset =
+        objectFieldOffset(UNSAFE, "head", ConcurrentSkipListMap.class);
+
+    static long objectFieldOffset(sun.misc.Unsafe UNSAFE,
+                                  String field, Class<?> klazz) {
+        try {
+            return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));
+        } catch (NoSuchFieldException e) {
+            // Convert Exception to corresponding Error
+            NoSuchFieldError error = new NoSuchFieldError(field);
+            error.initCause(e);
+            throw error;
+        }
+    }
+
 }

src/share/classes/java/util/concurrent/CopyOnWriteArrayList.java

@@ -832,7 +832,7 @@ public class CopyOnWriteArrayList<E>
     }
 
     /**
-     * Save the state of the list to a stream (i.e., serialize it).
+     * Saves the state of the list to a stream (that is, serializes it).
      *
      * @serialData The length of the array backing the list is emitted
      *               (int), followed by all of its elements (each an Object)
@@ -842,27 +842,25 @@ public class CopyOnWriteArrayList<E>
     private void writeObject(java.io.ObjectOutputStream s)
         throws java.io.IOException{
 
-        // Write out element count, and any hidden stuff
         s.defaultWriteObject();
 
         Object[] elements = getArray();
-        int len = elements.length;
         // Write out array length
-        s.writeInt(len);
+        s.writeInt(elements.length);
 
         // Write out all elements in the proper order.
-        for (int i = 0; i < len; i++)
-            s.writeObject(elements[i]);
+        for (Object element : elements)
+            s.writeObject(element);
     }
 
     /**
-     * Reconstitute the list from a stream (i.e., deserialize it).
+     * Reconstitutes the list from a stream (that is, deserializes it).
+     *
      * @param s the stream
      */
     private void readObject(java.io.ObjectInputStream s)
         throws java.io.IOException, ClassNotFoundException {
 
-        // Read in size, and any hidden stuff
         s.defaultReadObject();
 
         // bind to new lock

src/share/classes/java/util/concurrent/ForkJoinPool.java

@@ -526,7 +526,7 @@ public class ForkJoinPool extends AbstractExecutorService {
     private volatile long eventWaiters;
 
     private static final int EVENT_COUNT_SHIFT = 32;
-    private static final long WAITER_ID_MASK    = (1L << 16) - 1L;
+    private static final int WAITER_ID_MASK    = (1 << 16) - 1;
 
     /**
      * A counter for events that may wake up worker threads:
@@ -615,7 +615,7 @@ public class ForkJoinPool extends AbstractExecutorService {
     // are usually manually inlined by callers
 
     /**
-     * Increments running count part of workerCounts
+     * Increments running count part of workerCounts.
      */
     final void incrementRunningCount() {
         int c;
@@ -625,7 +625,17 @@ public class ForkJoinPool extends AbstractExecutorService {
     }
 
     /**
-     * Tries to decrement running count unless already zero
+     * Tries to increment running count part of workerCounts.
+     */
+    final boolean tryIncrementRunningCount() {
+        int c;
+        return UNSAFE.compareAndSwapInt(this, workerCountsOffset,
+                                        c = workerCounts,
+                                        c + ONE_RUNNING);
+    }
+
+    /**
+     * Tries to decrement running count unless already zero.
      */
     final boolean tryDecrementRunningCount() {
         int wc = workerCounts;
@@ -698,10 +708,11 @@ public class ForkJoinPool extends AbstractExecutorService {
                 for (k = 0; k < n && ws[k] != null; ++k)
                     ;
                 if (k == n)
-                    ws = Arrays.copyOf(ws, n << 1);
+                    ws = workers = Arrays.copyOf(ws, n << 1);
             }
             ws[k] = w;
-            workers = ws; // volatile array write ensures slot visibility
+            int c = eventCount; // advance event count to ensure visibility
+            UNSAFE.compareAndSwapInt(this, eventCountOffset, c, c+1);
         } finally {
             lock.unlock();
         }
@@ -734,7 +745,7 @@ public class ForkJoinPool extends AbstractExecutorService {
      */
     final void workerTerminated(ForkJoinWorkerThread w) {
         forgetWorker(w);
-        decrementWorkerCounts(w.isTrimmed()? 0 : ONE_RUNNING, ONE_TOTAL);
+        decrementWorkerCounts(w.isTrimmed() ? 0 : ONE_RUNNING, ONE_TOTAL);
         while (w.stealCount != 0) // collect final count
             tryAccumulateStealCount(w);
         tryTerminate(false);
@@ -746,24 +757,23 @@ public class ForkJoinPool extends AbstractExecutorService {
      * Releases workers blocked on a count not equal to current count.
      * Normally called after precheck that eventWaiters isn't zero to
      * avoid wasted array checks. Gives up upon a change in count or
-     * upon releasing two workers, letting others take over.
+     * upon releasing four workers, letting others take over.
      */
     private void releaseEventWaiters() {
         ForkJoinWorkerThread[] ws = workers;
         int n = ws.length;
         long h = eventWaiters;
         int ec = eventCount;
-        boolean releasedOne = false;
+        int releases = 4;
         ForkJoinWorkerThread w; int id;
-        while ((id = ((int)(h & WAITER_ID_MASK)) - 1) >= 0 &&
+        while ((id = (((int)h) & WAITER_ID_MASK) - 1) >= 0 &&
                (int)(h >>> EVENT_COUNT_SHIFT) != ec &&
                id < n && (w = ws[id]) != null) {
             if (UNSAFE.compareAndSwapLong(this, eventWaitersOffset,
                                           h,  w.nextWaiter)) {
                 LockSupport.unpark(w);
-                if (releasedOne) // exit on second release
+                if (--releases == 0)
                     break;
-                releasedOne = true;
             }
             if (eventCount != ec)
                 break;
@@ -793,7 +803,7 @@ public class ForkJoinPool extends AbstractExecutorService {
         long nh = (((long)ec) << EVENT_COUNT_SHIFT) | ((long)(w.poolIndex+1));
         long h;
         while ((runState < SHUTDOWN || !tryTerminate(false)) &&
-               (((int)((h = eventWaiters) & WAITER_ID_MASK)) == 0 ||
+               (((int)(h = eventWaiters) & WAITER_ID_MASK) == 0 ||
                 (int)(h >>> EVENT_COUNT_SHIFT) == ec) &&
                eventCount == ec) {
             if (UNSAFE.compareAndSwapLong(this, eventWaitersOffset,
@@ -820,9 +830,9 @@ public class ForkJoinPool extends AbstractExecutorService {
             if (tryAccumulateStealCount(w)) { // transfer while idle
                 boolean untimed = (w.nextWaiter != 0L ||
                                    (workerCounts & RUNNING_COUNT_MASK) <= 1);
-                long startTime = untimed? 0 : System.nanoTime();
+                long startTime = untimed ? 0 : System.nanoTime();
                 Thread.interrupted();         // clear/ignore interrupt
-                if (eventCount != ec || w.isTerminating())
+                if (w.isTerminating() || eventCount != ec)
                     break;                    // recheck after clear
                 if (untimed)
                     LockSupport.park(w);
@@ -860,7 +870,8 @@ public class ForkJoinPool extends AbstractExecutorService {
         if ((sw = spareWaiters) != 0 &&
             (id = (sw & SPARE_ID_MASK) - 1) >= 0 &&
             id < n && (w = ws[id]) != null &&
-            (workerCounts & RUNNING_COUNT_MASK) < parallelism &&
+            (runState >= TERMINATING ||
+             (workerCounts & RUNNING_COUNT_MASK) < parallelism) &&
             spareWaiters == sw &&
             UNSAFE.compareAndSwapInt(this, spareWaitersOffset,
                                      sw, w.nextSpare)) {
@@ -914,14 +925,10 @@ public class ForkJoinPool extends AbstractExecutorService {
                     break;
                 }
                 w.start(recordWorker(w), ueh);
-                if ((workerCounts >>> TOTAL_COUNT_SHIFT) >= pc) {
-                    int c; // advance event count
-                    UNSAFE.compareAndSwapInt(this, eventCountOffset,
-                                             c = eventCount, c+1);
+                if ((workerCounts >>> TOTAL_COUNT_SHIFT) >= pc)
                     break; // add at most one unless total below target
             }
         }
-        }
         if (eventWaiters != 0L)
             releaseEventWaiters();
     }
@@ -955,7 +962,7 @@ public class ForkJoinPool extends AbstractExecutorService {
             }
             else if ((h = eventWaiters) != 0L) {
                 long nh;
-                int id = ((int)(h & WAITER_ID_MASK)) - 1;
+                int id = (((int)h) & WAITER_ID_MASK) - 1;
                 if (id >= 0 && id < n && (w = ws[id]) != null &&
                     (nh = w.nextWaiter) != 0L && // keep at least one worker
                     UNSAFE.compareAndSwapLong(this, eventWaitersOffset, h, nh))
@@ -1008,19 +1015,26 @@ public class ForkJoinPool extends AbstractExecutorService {
                 break;
             }
             if ((inactivate || (active && (rs & ACTIVE_COUNT_MASK) >= pc)) &&
-                UNSAFE.compareAndSwapInt(this, runStateOffset, rs, rs - 1))
+                UNSAFE.compareAndSwapInt(this, runStateOffset, rs, --rs)) {
                 inactivate = active = w.active = false;
-            int wc = workerCounts;
+                if (rs == SHUTDOWN) {          // all inactive and shut down
+                    tryTerminate(false);
+                    continue;
+                }
+            }
+            int wc = workerCounts;             // try to suspend as spare
             if ((wc & RUNNING_COUNT_MASK) > pc) {
                 if (!(inactivate |= active) && // must inactivate to suspend
-                    workerCounts == wc &&      // try to suspend as spare
+                    workerCounts == wc &&
                     UNSAFE.compareAndSwapInt(this, workerCountsOffset,
                                              wc, wc - ONE_RUNNING))
                     w.suspendAsSpare();
             }
             else if ((wc >>> TOTAL_COUNT_SHIFT) < pc)
                 helpMaintainParallelism();     // not enough workers
-            else if (!ran) {
+            else if (ran)
+                break;
+            else {
                 long h = eventWaiters;
                 int ec = eventCount;
                 if (h != 0L && (int)(h >>> EVENT_COUNT_SHIFT) != ec)
@@ -1032,8 +1046,6 @@ public class ForkJoinPool extends AbstractExecutorService {
                 else if (!(inactivate |= active))
                     eventSync(w, wec);         // must inactivate before sync
             }
-            else
-                break;
         }
     }
 
@@ -1043,35 +1055,67 @@ public class ForkJoinPool extends AbstractExecutorService {
      *
      * @param joinMe the task to join
      * @param worker the current worker thread
+     * @param timed true if wait should time out
+     * @param nanos timeout value if timed
      */
-    final void awaitJoin(ForkJoinTask<?> joinMe, ForkJoinWorkerThread worker) {
+    final void awaitJoin(ForkJoinTask<?> joinMe, ForkJoinWorkerThread worker,
+                         boolean timed, long nanos) {
+        long startTime = timed ? System.nanoTime() : 0L;
         int retries = 2 + (parallelism >> 2); // #helpJoins before blocking
+        boolean running = true;               // false when count decremented
         while (joinMe.status >= 0) {
-            int wc;
-            worker.helpJoinTask(joinMe);
+            if (runState >= TERMINATING) {
+                joinMe.cancelIgnoringExceptions();
+                break;
+            }
+            running = worker.helpJoinTask(joinMe, running);
             if (joinMe.status < 0)
                 break;
-            else if (retries > 0)
+            if (retries > 0) {
                 --retries;
-            else if (((wc = workerCounts) & RUNNING_COUNT_MASK) != 0 &&
-                     UNSAFE.compareAndSwapInt(this, workerCountsOffset,
-                                              wc, wc - ONE_RUNNING)) {
-                int stat, c; long h;
-                while ((stat = joinMe.status) >= 0 &&
-                       (h = eventWaiters) != 0L && // help release others
-                       (int)(h >>> EVENT_COUNT_SHIFT) != eventCount)
+                continue;
+            }
+            int wc = workerCounts;
+            if ((wc & RUNNING_COUNT_MASK) != 0) {
+                if (running) {
+                    if (!UNSAFE.compareAndSwapInt(this, workerCountsOffset,
+                                                  wc, wc - ONE_RUNNING))
+                        continue;
+                    running = false;
+                }
+                long h = eventWaiters;
+                if (h != 0L && (int)(h >>> EVENT_COUNT_SHIFT) != eventCount)
                     releaseEventWaiters();
-                if (stat >= 0 &&
-                    ((workerCounts & RUNNING_COUNT_MASK) == 0 ||
-                     (stat =
-                      joinMe.internalAwaitDone(JOIN_TIMEOUT_MILLIS)) >= 0))
-                    helpMaintainParallelism(); // timeout or no running workers
+                if ((workerCounts & RUNNING_COUNT_MASK) != 0) {
+                    long ms; int ns;
+                    if (!timed) {
+                        ms = JOIN_TIMEOUT_MILLIS;
+                        ns = 0;
+                    }
+                    else { // at most JOIN_TIMEOUT_MILLIS per wait
+                        long nt = nanos - (System.nanoTime() - startTime);
+                        if (nt <= 0L)
+                            break;
+                        ms = nt / 1000000;
+                        if (ms > JOIN_TIMEOUT_MILLIS) {
+                            ms = JOIN_TIMEOUT_MILLIS;
+                            ns = 0;
+                        }
+                        else
+                            ns = (int) (nt % 1000000);
+                    }
+                    joinMe.internalAwaitDone(ms, ns);
+                }
+                if (joinMe.status < 0)
+                    break;
+            }
+            helpMaintainParallelism();
+        }
+        if (!running) {
+            int c;
             do {} while (!UNSAFE.compareAndSwapInt
                          (this, workerCountsOffset,
                           c = workerCounts, c + ONE_RUNNING));
-                if (stat < 0)
-                    break;   // else restart
-            }
         }
     }
 
@@ -1082,8 +1126,9 @@ public class ForkJoinPool extends AbstractExecutorService {
         throws InterruptedException {
         while (!blocker.isReleasable()) {
             int wc = workerCounts;
-            if ((wc & RUNNING_COUNT_MASK) != 0 &&
-                UNSAFE.compareAndSwapInt(this, workerCountsOffset,
+            if ((wc & RUNNING_COUNT_MASK) == 0)
+                helpMaintainParallelism();
+            else if (UNSAFE.compareAndSwapInt(this, workerCountsOffset,
                                               wc, wc - ONE_RUNNING)) {
                 try {
                     while (!blocker.isReleasable()) {
@@ -1129,12 +1174,11 @@ public class ForkJoinPool extends AbstractExecutorService {
         // Finish now if all threads terminated; else in some subsequent call
         if ((workerCounts >>> TOTAL_COUNT_SHIFT) == 0) {
             advanceRunLevel(TERMINATED);
-            termination.arrive();
+            termination.forceTermination();
         }
         return true;
     }
 
-
     /**
      * Actions on transition to TERMINATING
      *
@@ -1325,17 +1369,13 @@ public class ForkJoinPool extends AbstractExecutorService {
     // Execution methods
 
     /**
-     * Common code for execute, invoke and submit
+     * Submits task and creates, starts, or resumes some workers if necessary
      */
     private <T> void doSubmit(ForkJoinTask<T> task) {
-        if (task == null)
-            throw new NullPointerException();
-        if (runState >= SHUTDOWN)
-            throw new RejectedExecutionException();
         submissionQueue.offer(task);
         int c; // try to increment event count -- CAS failure OK
         UNSAFE.compareAndSwapInt(this, eventCountOffset, c = eventCount, c+1);
-        helpMaintainParallelism(); // create, start, or resume some workers
+        helpMaintainParallelism();
     }
 
     /**
@@ -1348,9 +1388,34 @@ public class ForkJoinPool extends AbstractExecutorService {
      *         scheduled for execution
      */
     public <T> T invoke(ForkJoinTask<T> task) {
+        if (task == null)
+            throw new NullPointerException();
+        if (runState >= SHUTDOWN)
+            throw new RejectedExecutionException();
+        Thread t = Thread.currentThread();
+        if ((t instanceof ForkJoinWorkerThread) &&
+            ((ForkJoinWorkerThread)t).pool == this)
+            return task.invoke();  // bypass submit if in same pool
+        else {
             doSubmit(task);
             return task.join();
         }
+    }
+
+    /**
+     * Unless terminating, forks task if within an ongoing FJ
+     * computation in the current pool, else submits as external task.
+     */
+    private <T> void forkOrSubmit(ForkJoinTask<T> task) {
+        if (runState >= SHUTDOWN)
+            throw new RejectedExecutionException();
+        Thread t = Thread.currentThread();
+        if ((t instanceof ForkJoinWorkerThread) &&
+            ((ForkJoinWorkerThread)t).pool == this)
+            task.fork();
+        else
+            doSubmit(task);
+    }
 
     /**
      * Arranges for (asynchronous) execution of the given task.
@@ -1361,7 +1426,9 @@ public class ForkJoinPool extends AbstractExecutorService {
      *         scheduled for execution
      */
     public void execute(ForkJoinTask<?> task) {
-        doSubmit(task);
+        if (task == null)
+            throw new NullPointerException();
+        forkOrSubmit(task);
     }
 
     // AbstractExecutorService methods
@@ -1372,12 +1439,14 @@ public class ForkJoinPool extends AbstractExecutorService {
      *         scheduled for execution
      */
     public void execute(Runnable task) {
+        if (task == null)
+            throw new NullPointerException();
         ForkJoinTask<?> job;
         if (task instanceof ForkJoinTask<?>) // avoid re-wrap
             job = (ForkJoinTask<?>) task;
         else
             job = ForkJoinTask.adapt(task, null);
-        doSubmit(job);
+        forkOrSubmit(job);
     }
 
     /**
@@ -1390,7 +1459,9 @@ public class ForkJoinPool extends AbstractExecutorService {
      *         scheduled for execution
      */
     public <T> ForkJoinTask<T> submit(ForkJoinTask<T> task) {
-        doSubmit(task);
+        if (task == null)
+            throw new NullPointerException();
+        forkOrSubmit(task);
         return task;
     }
 
@@ -1400,8 +1471,10 @@ public class ForkJoinPool extends AbstractExecutorService {
      *         scheduled for execution
      */
     public <T> ForkJoinTask<T> submit(Callable<T> task) {
+        if (task == null)
+            throw new NullPointerException();
         ForkJoinTask<T> job = ForkJoinTask.adapt(task);
-        doSubmit(job);
+        forkOrSubmit(job);
         return job;
     }
 
@@ -1411,8 +1484,10 @@ public class ForkJoinPool extends AbstractExecutorService {
      *         scheduled for execution
      */
     public <T> ForkJoinTask<T> submit(Runnable task, T result) {
+        if (task == null)
+            throw new NullPointerException();
         ForkJoinTask<T> job = ForkJoinTask.adapt(task, result);
-        doSubmit(job);
+        forkOrSubmit(job);
         return job;
     }
 
@@ -1422,12 +1497,14 @@ public class ForkJoinPool extends AbstractExecutorService {
      *         scheduled for execution
      */
     public ForkJoinTask<?> submit(Runnable task) {
+        if (task == null)
+            throw new NullPointerException();
         ForkJoinTask<?> job;
         if (task instanceof ForkJoinTask<?>) // avoid re-wrap
             job = (ForkJoinTask<?>) task;
         else
             job = ForkJoinTask.adapt(task, null);
-        doSubmit(job);
+        forkOrSubmit(job);
         return job;
     }
 
@@ -1725,8 +1802,11 @@ public class ForkJoinPool extends AbstractExecutorService {
      * commenced but not yet completed.  This method may be useful for
      * debugging. A return of {@code true} reported a sufficient
      * period after shutdown may indicate that submitted tasks have
-     * ignored or suppressed interruption, causing this executor not
-     * to properly terminate.
+     * ignored or suppressed interruption, or are waiting for IO,
+     * causing this executor not to properly terminate. (See the
+     * advisory notes for class {@link ForkJoinTask} stating that
+     * tasks should not normally entail blocking operations.  But if
+     * they do, they must abort them on interrupt.)
      *
      * @return {@code true} if terminating but not yet terminated
      */
@@ -1764,10 +1844,11 @@ public class ForkJoinPool extends AbstractExecutorService {
     public boolean awaitTermination(long timeout, TimeUnit unit)
         throws InterruptedException {
         try {
-            return termination.awaitAdvanceInterruptibly(0, timeout, unit) > 0;
+            termination.awaitAdvanceInterruptibly(0, timeout, unit);
         } catch (TimeoutException ex) {
             return false;
         }
+        return true;
     }
 
     /**

src/share/classes/java/util/concurrent/ForkJoinWorkerThread.java

@@ -38,16 +38,18 @@ package java.util.concurrent;
 import java.util.Random;
 import java.util.Collection;
 import java.util.concurrent.locks.LockSupport;
+import java.util.concurrent.RejectedExecutionException;
 
 /**
- * A thread managed by a {@link ForkJoinPool}.  This class is
- * subclassable solely for the sake of adding functionality -- there
- * are no overridable methods dealing with scheduling or execution.
- * However, you can override initialization and termination methods
- * surrounding the main task processing loop.  If you do create such a
- * subclass, you will also need to supply a custom {@link
- * ForkJoinPool.ForkJoinWorkerThreadFactory} to use it in a {@code
- * ForkJoinPool}.
+ * A thread managed by a {@link ForkJoinPool}, which executes
+ * {@link ForkJoinTask}s.
+ * This class is subclassable solely for the sake of adding
+ * functionality -- there are no overridable methods dealing with
+ * scheduling or execution.  However, you can override initialization
+ * and termination methods surrounding the main task processing loop.
+ * If you do create such a subclass, you will also need to supply a
+ * custom {@link ForkJoinPool.ForkJoinWorkerThreadFactory} to use it
+ * in a {@code ForkJoinPool}.
  *
  * @since 1.7
  * @author Doug Lea
@@ -376,7 +378,7 @@ public class ForkJoinWorkerThread extends Thread {
     /**
      * Initializes internal state after construction but before
      * processing any tasks. If you override this method, you must
-     * invoke @code{super.onStart()} at the beginning of the method.
+     * invoke {@code super.onStart()} at the beginning of the method.
      * Initialization requires care: Most fields must have legal
      * default values, to ensure that attempted accesses from other
      * threads work correctly even before this thread starts
@@ -384,7 +386,7 @@ public class ForkJoinWorkerThread extends Thread {
      */
     protected void onStart() {
         int rs = seedGenerator.nextInt();
-        seed = rs == 0? 1 : rs; // seed must be nonzero
+        seed = (rs == 0) ? 1 : rs; // seed must be nonzero
 
         // Allocate name string and arrays in this thread
         String pid = Integer.toString(pool.getPoolNumber());
@@ -426,7 +428,7 @@ public class ForkJoinWorkerThread extends Thread {
     /**
      * This method is required to be public, but should never be
      * called explicitly. It performs the main run loop to execute
-     * ForkJoinTasks.
+     * {@link ForkJoinTask}s.
      */
     public void run() {
         Throwable exception = null;
@@ -628,6 +630,19 @@ public class ForkJoinWorkerThread extends Thread {
                 if (t == null)   // lost to stealer
                     break;
                 if (UNSAFE.compareAndSwapObject(q, u, t, null)) {
+                    /*
+                     * Note: here and in related methods, as a
+                     * performance (not correctness) issue, we'd like
+                     * to encourage compiler not to arbitrarily
+                     * postpone setting sp after successful CAS.
+                     * Currently there is no intrinsic for arranging
+                     * this, but using Unsafe putOrderedInt may be a
+                     * preferable strategy on some compilers even
+                     * though its main effect is a pre-, not post-
+                     * fence. To simplify possible changes, the option
+                     * is left in comments next to the associated
+                     * assignments.
+                     */
                     sp = s; // putOrderedInt may encourage more timely write
                     // UNSAFE.putOrderedInt(this, spOffset, s);
                     return t;
@@ -884,8 +899,7 @@ public class ForkJoinWorkerThread extends Thread {
      */
     final void cancelTasks() {
         ForkJoinTask<?> cj = currentJoin; // try to cancel ongoing tasks
-        if (cj != null) {
-            currentJoin = null;
+        if (cj != null && cj.status >= 0) {
             cj.cancelIgnoringExceptions();
             try {
                 this.interrupt(); // awaken wait
@@ -893,10 +907,8 @@ public class ForkJoinWorkerThread extends Thread {
             }
         }
         ForkJoinTask<?> cs = currentSteal;
-        if (cs != null) {
-            currentSteal = null;
+        if (cs != null && cs.status >= 0)
             cs.cancelIgnoringExceptions();
-        }
         while (base != sp) {
             ForkJoinTask<?> t = deqTask();
             if (t != null)
@@ -959,57 +971,23 @@ public class ForkJoinWorkerThread extends Thread {
      * Possibly runs some tasks and/or blocks, until task is done.
      *
      * @param joinMe the task to join
+     * @param timed true if use timed wait
+     * @param nanos wait time if timed
      */
-    final void joinTask(ForkJoinTask<?> joinMe) {
+    final void joinTask(ForkJoinTask<?> joinMe, boolean timed, long nanos) {
         // currentJoin only written by this thread; only need ordered store
         ForkJoinTask<?> prevJoin = currentJoin;
         UNSAFE.putOrderedObject(this, currentJoinOffset, joinMe);
-        if (sp != base)
-            localHelpJoinTask(joinMe);
-        if (joinMe.status >= 0)
-            pool.awaitJoin(joinMe, this);
+        pool.awaitJoin(joinMe, this, timed, nanos);
         UNSAFE.putOrderedObject(this, currentJoinOffset, prevJoin);
     }
 
     /**
-     * Run tasks in local queue until given task is done.
-     *
-     * @param joinMe the task to join
-     */
-    private void localHelpJoinTask(ForkJoinTask<?> joinMe) {
-        int s;
-        ForkJoinTask<?>[] q;
-        while (joinMe.status >= 0 && (s = sp) != base && (q = queue) != null) {
-            int i = (q.length - 1) & --s;
-            long u = (i << qShift) + qBase; // raw offset
-            ForkJoinTask<?> t = q[i];
-            if (t == null)  // lost to a stealer
-                break;
-            if (UNSAFE.compareAndSwapObject(q, u, t, null)) {
-                /*
-                 * This recheck (and similarly in helpJoinTask)
-                 * handles cases where joinMe is independently
-                 * cancelled or forced even though there is other work
-                 * available. Back out of the pop by putting t back
-                 * into slot before we commit by writing sp.
-                 */
-                if (joinMe.status < 0) {
-                    UNSAFE.putObjectVolatile(q, u, t);
-                    break;
-                }
-                sp = s;
-                // UNSAFE.putOrderedInt(this, spOffset, s);
-                t.quietlyExec();
-            }
-        }
-    }
-
-    /**
-     * Unless terminating, tries to locate and help perform tasks for
-     * a stealer of the given task, or in turn one of its stealers.
-     * Traces currentSteal->currentJoin links looking for a thread
-     * working on a descendant of the given task and with a non-empty
-     * queue to steal back and execute tasks from.
+     * Tries to locate and help perform tasks for a stealer of the
+     * given task, or in turn one of its stealers.  Traces
+     * currentSteal->currentJoin links looking for a thread working on
+     * a descendant of the given task and with a non-empty queue to
+     * steal back and execute tasks from.
      *
      * The implementation is very branchy to cope with potential
      * inconsistencies or loops encountering chains that are stale,
@@ -1019,22 +997,54 @@ public class ForkJoinWorkerThread extends Thread {
      * don't work out.
      *
      * @param joinMe the task to join
+     * @param running if false, then must update pool count upon
+     *  running a task
+     * @return value of running on exit
      */
-    final void helpJoinTask(ForkJoinTask<?> joinMe) {
-        ForkJoinWorkerThread[] ws;
-        int n;
-        if (joinMe.status < 0)                // already done
-            return;
-        if ((runState & TERMINATING) != 0) {  // cancel if shutting down
+    final boolean helpJoinTask(ForkJoinTask<?> joinMe, boolean running) {
+        /*
+         * Initial checks to (1) abort if terminating; (2) clean out
+         * old cancelled tasks from local queue; (3) if joinMe is next
+         * task, run it; (4) omit scan if local queue nonempty (since
+         * it may contain non-descendents of joinMe).
+         */
+        ForkJoinPool p = pool;
+        for (;;) {
+            ForkJoinTask<?>[] q;
+            int s;
+            if (joinMe.status < 0)
+                return running;
+            else if ((runState & TERMINATING) != 0) {
                 joinMe.cancelIgnoringExceptions();
-            return;
+                return running;
+            }
+            else if ((s = sp) == base || (q = queue) == null)
+                break;                            // queue empty
+            else {
+                int i = (q.length - 1) & --s;
+                long u = (i << qShift) + qBase;   // raw offset
+                ForkJoinTask<?> t = q[i];
+                if (t == null)
+                    break;                        // lost to a stealer
+                else if (t != joinMe && t.status >= 0)
+                    return running;               // cannot safely help
+                else if ((running ||
+                          (running = p.tryIncrementRunningCount())) &&
+                         UNSAFE.compareAndSwapObject(q, u, t, null)) {
+                    sp = s; // putOrderedInt may encourage more timely write
+                    // UNSAFE.putOrderedInt(this, spOffset, s);
+                    t.quietlyExec();
+                }
+            }
         }
-        if ((ws = pool.workers) == null || (n = ws.length) <= 1)
-            return;                           // need at least 2 workers
 
+        int n;                                    // worker array size
+        ForkJoinWorkerThread[] ws = p.workers;
+        if (ws != null && (n = ws.length) > 1) {  // need at least 2 workers
             ForkJoinTask<?> task = joinMe;        // base of chain
             ForkJoinWorkerThread thread = this;   // thread with stolen task
-        for (int d = 0; d < MAX_HELP_DEPTH; ++d) { // chain length
+
+            outer:for (int d = 0; d < MAX_HELP_DEPTH; ++d) { // chain length
                 // Try to find v, the stealer of task, by first using hint
                 ForkJoinWorkerThread v = ws[thread.stealHint & (n - 1)];
                 if (v == null || v.currentSteal != task) {
@@ -1043,54 +1053,72 @@ public class ForkJoinWorkerThread extends Thread {
                             ForkJoinTask<?> vs;
                             if ((v = ws[j]) != null &&
                                 (vs = v.currentSteal) != null) {
-                            if (joinMe.status < 0 || task.status < 0)
-                                return;       // stale or done
+                                if (joinMe.status < 0)
+                                    break outer;
                                 if (vs == task) {
+                                    if (task.status < 0)
+                                        break outer; // stale
                                     thread.stealHint = j;
                                     break;        // save hint for next time
                                 }
                             }
                         }
                         else
-                        return;               // no stealer
+                            break outer;          // no stealer
                     }
                 }
-            for (;;) { // Try to help v, using specialized form of deqTask
+
+                // Try to help v, using specialized form of deqTask
+                for (;;) {
                     if (joinMe.status < 0)
-                    return;
+                        break outer;
                     int b = v.base;
                     ForkJoinTask<?>[] q = v.queue;
                     if (b == v.sp || q == null)
-                    break;
+                        break;                    // empty
                     int i = (q.length - 1) & b;
                     long u = (i << qShift) + qBase;
                     ForkJoinTask<?> t = q[i];
-                int pid = poolIndex;
-                ForkJoinTask<?> ps = currentSteal;
                     if (task.status < 0)
-                    return;                   // stale or done
-                if (t != null && v.base == b++ &&
+                        break outer;              // stale
+                    if (t != null &&
+                        (running ||
+                         (running = p.tryIncrementRunningCount())) &&
+                        v.base == b++ &&
                         UNSAFE.compareAndSwapObject(q, u, t, null)) {
-                    if (joinMe.status < 0) {
+                        if (t != joinMe && joinMe.status < 0) {
                             UNSAFE.putObjectVolatile(q, u, t);
-                        return;               // back out on cancel
+                            break outer;          // joinMe cancelled; back out
                         }
                         v.base = b;
+                        if (t.status >= 0) {
+                            ForkJoinTask<?> ps = currentSteal;
+                            int pid = poolIndex;
                             v.stealHint = pid;
-                    UNSAFE.putOrderedObject(this, currentStealOffset, t);
+                            UNSAFE.putOrderedObject(this,
+                                                    currentStealOffset, t);
                             t.quietlyExec();
-                    UNSAFE.putOrderedObject(this, currentStealOffset, ps);
+                            UNSAFE.putOrderedObject(this,
+                                                    currentStealOffset, ps);
+                        }
+                    }
+                    else if ((runState & TERMINATING) != 0) {
+                        joinMe.cancelIgnoringExceptions();
+                        break outer;
                     }
                 }
+
                 // Try to descend to find v's stealer
                 ForkJoinTask<?> next = v.currentJoin;
                 if (task.status < 0 || next == null || next == task ||
                     joinMe.status < 0)
-                return;
+                    break;                 // done, stale, dead-end, or cyclic
                 task = next;
                 thread = v;
             }
         }
+        return running;
+    }
 
     /**
      * Implements ForkJoinTask.getSurplusQueuedTaskCount().

src/share/classes/java/util/concurrent/LinkedBlockingDeque.java

@@ -1029,6 +1029,8 @@ public class LinkedBlockingDeque<E>
      * elements as they existed upon construction of the iterator, and
      * may (but is not guaranteed to) reflect any modifications
      * subsequent to construction.
+     *
+     * @return an iterator over the elements in this deque in reverse order
      */
     public Iterator<E> descendingIterator() {
         return new DescendingItr();

src/share/classes/java/util/concurrent/LinkedBlockingQueue.java

@@ -189,14 +189,14 @@ public class LinkedBlockingQueue<E> extends AbstractQueue<E>
     }
 
     /**
-     * Creates a node and links it at end of queue.
+     * Links node at end of queue.
      *
-     * @param x the item
+     * @param node the node
      */
-    private void enqueue(E x) {
+    private void enqueue(Node<E> node) {
         // assert putLock.isHeldByCurrentThread();
         // assert last.next == null;
-        last = last.next = new Node<E>(x);
+        last = last.next = node;
     }
 
     /**
@@ -282,7 +282,7 @@ public class LinkedBlockingQueue<E> extends AbstractQueue<E>
                     throw new NullPointerException();
                 if (n == capacity)
                     throw new IllegalStateException("Queue full");
-                enqueue(e);
+                enqueue(new Node<E>(e));
                 ++n;
             }
             count.set(n);
@@ -332,6 +332,7 @@ public class LinkedBlockingQueue<E> extends AbstractQueue<E>
         // Note: convention in all put/take/etc is to preset local var
         // holding count negative to indicate failure unless set.
         int c = -1;
+        Node<E> node = new Node(e);
         final ReentrantLock putLock = this.putLock;
         final AtomicInteger count = this.count;
         putLock.lockInterruptibly();
@@ -347,7 +348,7 @@ public class LinkedBlockingQueue<E> extends AbstractQueue<E>
             while (count.get() == capacity) {
                 notFull.await();
             }
-            enqueue(e);
+            enqueue(node);
             c = count.getAndIncrement();
             if (c + 1 < capacity)
                 notFull.signal();
@@ -382,7 +383,7 @@ public class LinkedBlockingQueue<E> extends AbstractQueue<E>
                     return false;
                 nanos = notFull.awaitNanos(nanos);
             }
-            enqueue(e);
+            enqueue(new Node<E>(e));
             c = count.getAndIncrement();
             if (c + 1 < capacity)
                 notFull.signal();
@@ -411,11 +412,12 @@ public class LinkedBlockingQueue<E> extends AbstractQueue<E>
         if (count.get() == capacity)
             return false;
         int c = -1;
+        Node<E> node = new Node(e);
         final ReentrantLock putLock = this.putLock;
         putLock.lock();
         try {
             if (count.get() < capacity) {
-                enqueue(e);
+                enqueue(node);
                 c = count.getAndIncrement();
                 if (c + 1 < capacity)
                     notFull.signal();
@@ -559,6 +561,27 @@ public class LinkedBlockingQueue<E> extends AbstractQueue<E>
         }
     }
 
+    /**
+     * Returns {@code true} if this queue contains the specified element.
+     * More formally, returns {@code true} if and only if this queue contains
+     * at least one element {@code e} such that {@code o.equals(e)}.
+     *
+     * @param o object to be checked for containment in this queue
+     * @return {@code true} if this queue contains the specified element
+     */
+    public boolean contains(Object o) {
+        if (o == null) return false;
+        fullyLock();
+        try {
+            for (Node<E> p = head.next; p != null; p = p.next)
+                if (o.equals(p.item))
+                    return true;
+            return false;
+        } finally {
+            fullyUnlock();
+        }
+    }
+
     /**
      * Returns an array containing all of the elements in this queue, in
      * proper sequence.
@@ -645,7 +668,20 @@ public class LinkedBlockingQueue<E> extends AbstractQueue<E>
     public String toString() {
         fullyLock();
         try {
-            return super.toString();
+            Node<E> p = head.next;
+            if (p == null)
+                return "[]";
+
+            StringBuilder sb = new StringBuilder();
+            sb.append('[');
+            for (;;) {
+                E e = p.item;
+                sb.append(e == this ? "(this Collection)" : e);
+                p = p.next;
+                if (p == null)
+                    return sb.append(']').toString();
+                sb.append(',').append(' ');
+            }
         } finally {
             fullyUnlock();
         }
@@ -727,12 +763,14 @@ public class LinkedBlockingQueue<E> extends AbstractQueue<E>
 
     /**
      * Returns an iterator over the elements in this queue in proper sequence.
-     * The returned {@code Iterator} is a "weakly consistent" iterator that
+     * The elements will be returned in order from first (head) to last (tail).
+     *
+     * <p>The returned iterator is a "weakly consistent" iterator that
      * will never throw {@link java.util.ConcurrentModificationException
-     * ConcurrentModificationException},
-     * and guarantees to traverse elements as they existed upon
-     * construction of the iterator, and may (but is not guaranteed to)
-     * reflect any modifications subsequent to construction.
+     * ConcurrentModificationException}, and guarantees to traverse
+     * elements as they existed upon construction of the iterator, and
+     * may (but is not guaranteed to) reflect any modifications
+     * subsequent to construction.
      *
      * @return an iterator over the elements in this queue in proper sequence
      */

src/share/classes/java/util/concurrent/LinkedTransferQueue.java

@@ -37,10 +37,10 @@ package java.util.concurrent;
 
 import java.util.AbstractQueue;
 import java.util.Collection;
-import java.util.ConcurrentModificationException;
 import java.util.Iterator;
 import java.util.NoSuchElementException;
 import java.util.Queue;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.LockSupport;
 
 /**
@@ -588,7 +588,8 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
             throw new NullPointerException();
         Node s = null;                        // the node to append, if needed
 
-        retry: for (;;) {                     // restart on append race
+        retry:
+        for (;;) {                            // restart on append race
 
             for (Node h = head, p = h; p != null;) { // find & match first node
                 boolean isData = p.isData;
@@ -599,7 +600,7 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
                     if (p.casItem(item, e)) { // match
                         for (Node q = p; q != h;) {
                             Node n = q.next;  // update by 2 unless singleton
-                            if (head == h && casHead(h, n == null? q : n)) {
+                            if (head == h && casHead(h, n == null ? q : n)) {
                                 h.forgetNext();
                                 break;
                             }                 // advance and retry
@@ -809,22 +810,61 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
          * Moves to next node after prev, or first node if prev null.
          */
         private void advance(Node prev) {
-            lastPred = lastRet;
-            lastRet = prev;
-            for (Node p = (prev == null) ? head : succ(prev);
-                 p != null; p = succ(p)) {
-                Object item = p.item;
-                if (p.isData) {
-                    if (item != null && item != p) {
-                        nextItem = LinkedTransferQueue.this.<E>cast(item);
-                        nextNode = p;
+            /*
+             * To track and avoid buildup of deleted nodes in the face
+             * of calls to both Queue.remove and Itr.remove, we must
+             * include variants of unsplice and sweep upon each
+             * advance: Upon Itr.remove, we may need to catch up links
+             * from lastPred, and upon other removes, we might need to
+             * skip ahead from stale nodes and unsplice deleted ones
+             * found while advancing.
+             */
+
+            Node r, b; // reset lastPred upon possible deletion of lastRet
+            if ((r = lastRet) != null && !r.isMatched())
+                lastPred = r;    // next lastPred is old lastRet
+            else if ((b = lastPred) == null || b.isMatched())
+                lastPred = null; // at start of list
+            else {
+                Node s, n;       // help with removal of lastPred.next
+                while ((s = b.next) != null &&
+                       s != b && s.isMatched() &&
+                       (n = s.next) != null && n != s)
+                    b.casNext(s, n);
+            }
+
+            this.lastRet = prev;
+
+            for (Node p = prev, s, n;;) {
+                s = (p == null) ? head : p.next;
+                if (s == null)
+                    break;
+                else if (s == p) {
+                    p = null;
+                    continue;
+                }
+                Object item = s.item;
+                if (s.isData) {
+                    if (item != null && item != s) {
+                        nextItem = LinkedTransferQueue.<E>cast(item);
+                        nextNode = s;
                         return;
                     }
                 }
                 else if (item == null)
                     break;
+                // assert s.isMatched();
+                if (p == null)
+                    p = s;
+                else if ((n = s.next) == null)
+                    break;
+                else if (s == n)
+                    p = null;
+                else
+                    p.casNext(s, n);
             }
             nextNode = null;
+            nextItem = null;
         }
 
         Itr() {
@@ -844,10 +884,12 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
         }
 
         public final void remove() {
-            Node p = lastRet;
-            if (p == null) throw new IllegalStateException();
-            if (p.tryMatchData())
-                unsplice(lastPred, p);
+            final Node lastRet = this.lastRet;
+            if (lastRet == null)
+                throw new IllegalStateException();
+            this.lastRet = null;
+            if (lastRet.tryMatchData())
+                unsplice(lastPred, lastRet);
         }
     }
 
@@ -997,8 +1039,7 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
      * Inserts the specified element at the tail of this queue.
      * As the queue is unbounded, this method will never return {@code false}.
      *
-     * @return {@code true} (as specified by
-     *         {@link BlockingQueue#offer(Object) BlockingQueue.offer})
+     * @return {@code true} (as specified by {@link Queue#offer})
      * @throws NullPointerException if the specified element is null
      */
     public boolean offer(E e) {
@@ -1130,15 +1171,15 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
     }
 
     /**
-     * Returns an iterator over the elements in this queue in proper
-     * sequence, from head to tail.
+     * Returns an iterator over the elements in this queue in proper sequence.
+     * The elements will be returned in order from first (head) to last (tail).
      *
      * <p>The returned iterator is a "weakly consistent" iterator that
-     * will never throw
-     * {@link ConcurrentModificationException ConcurrentModificationException},
-     * and guarantees to traverse elements as they existed upon
-     * construction of the iterator, and may (but is not guaranteed
-     * to) reflect any modifications subsequent to construction.
+     * will never throw {@link java.util.ConcurrentModificationException
+     * ConcurrentModificationException}, and guarantees to traverse
+     * elements as they existed upon construction of the iterator, and
+     * may (but is not guaranteed to) reflect any modifications
+     * subsequent to construction.
      *
      * @return an iterator over the elements in this queue in proper sequence
      */
@@ -1202,6 +1243,28 @@ public class LinkedTransferQueue<E> extends AbstractQueue<E>
         return findAndRemove(o);
     }
 
+    /**
+     * Returns {@code true} if this queue contains the specified element.
+     * More formally, returns {@code true} if and only if this queue contains
+     * at least one element {@code e} such that {@code o.equals(e)}.
+     *
+     * @param o object to be checked for containment in this queue
+     * @return {@code true} if this queue contains the specified element
+     */
+    public boolean contains(Object o) {
+        if (o == null) return false;
+        for (Node p = head; p != null; p = succ(p)) {
+            Object item = p.item;
+            if (p.isData) {
+                if (item != null && item != p && o.equals(item))
+                    return true;
+            }
+            else if (item == null)
+                break;
+        }
+        return false;
+    }
+
     /**
      * Always returns {@code Integer.MAX_VALUE} because a
      * {@code LinkedTransferQueue} is not capacity constrained.

src/share/classes/java/util/concurrent/ScheduledThreadPoolExecutor.java

@@ -360,8 +360,12 @@ public class ScheduledThreadPoolExecutor
             getExecuteExistingDelayedTasksAfterShutdownPolicy();
         boolean keepPeriodic =
             getContinueExistingPeriodicTasksAfterShutdownPolicy();
-        if (!keepDelayed && !keepPeriodic)
+        if (!keepDelayed && !keepPeriodic) {
+            for (Object e : q.toArray())
+                if (e instanceof RunnableScheduledFuture<?>)
+                    ((RunnableScheduledFuture<?>) e).cancel(false);
             q.clear();
+        }
         else {
             // Traverse snapshot to avoid iterator exceptions
             for (Object e : q.toArray()) {

src/share/classes/java/util/concurrent/SynchronousQueue.java

@@ -163,7 +163,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
     /**
      * Shared internal API for dual stacks and queues.
      */
-    static abstract class Transferer {
+    abstract static class Transferer {
         /**
          * Performs a put or take.
          *
@@ -190,7 +190,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
      * seems not to vary with number of CPUs (beyond 2) so is just
      * a constant.
      */
-    static final int maxTimedSpins = (NCPUS < 2)? 0 : 32;
+    static final int maxTimedSpins = (NCPUS < 2) ? 0 : 32;
 
     /**
      * The number of times to spin before blocking in untimed waits.
@@ -241,19 +241,11 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
                 this.item = item;
             }
 
-            static final AtomicReferenceFieldUpdater<SNode, SNode>
-                nextUpdater = AtomicReferenceFieldUpdater.newUpdater
-                (SNode.class, SNode.class, "next");
-
             boolean casNext(SNode cmp, SNode val) {
-                return (cmp == next &&
-                        nextUpdater.compareAndSet(this, cmp, val));
+                return cmp == next &&
+                    UNSAFE.compareAndSwapObject(this, nextOffset, cmp, val);
             }
 
-            static final AtomicReferenceFieldUpdater<SNode, SNode>
-                matchUpdater = AtomicReferenceFieldUpdater.newUpdater
-                (SNode.class, SNode.class, "match");
-
             /**
              * Tries to match node s to this node, if so, waking up thread.
              * Fulfillers call tryMatch to identify their waiters.
@@ -264,7 +256,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
              */
             boolean tryMatch(SNode s) {
                 if (match == null &&
-                    matchUpdater.compareAndSet(this, null, s)) {
+                    UNSAFE.compareAndSwapObject(this, matchOffset, null, s)) {
                     Thread w = waiter;
                     if (w != null) {    // waiters need at most one unpark
                         waiter = null;
@@ -279,23 +271,28 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
              * Tries to cancel a wait by matching node to itself.
              */
             void tryCancel() {
-                matchUpdater.compareAndSet(this, null, this);
+                UNSAFE.compareAndSwapObject(this, matchOffset, null, this);
             }
 
             boolean isCancelled() {
                 return match == this;
             }
+
+            // Unsafe mechanics
+            private static final sun.misc.Unsafe UNSAFE = sun.misc.Unsafe.getUnsafe();
+            private static final long nextOffset =
+                objectFieldOffset(UNSAFE, "next", SNode.class);
+            private static final long matchOffset =
+                objectFieldOffset(UNSAFE, "match", SNode.class);
+
         }
 
         /** The head (top) of the stack */
         volatile SNode head;
 
-        static final AtomicReferenceFieldUpdater<TransferStack, SNode>
-            headUpdater = AtomicReferenceFieldUpdater.newUpdater
-            (TransferStack.class,  SNode.class, "head");
-
         boolean casHead(SNode h, SNode nh) {
-            return h == head && headUpdater.compareAndSet(this, h, nh);
+            return h == head &&
+                UNSAFE.compareAndSwapObject(this, headOffset, h, nh);
         }
 
         /**
@@ -338,7 +335,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
              */
 
             SNode s = null; // constructed/reused as needed
-            int mode = (e == null)? REQUEST : DATA;
+            int mode = (e == null) ? REQUEST : DATA;
 
             for (;;) {
                 SNode h = head;
@@ -356,7 +353,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
                         }
                         if ((h = head) != null && h.next == s)
                             casHead(h, s.next);     // help s's fulfiller
-                        return mode == REQUEST? m.item : s.item;
+                        return (mode == REQUEST) ? m.item : s.item;
                     }
                 } else if (!isFulfilling(h.mode)) { // try to fulfill
                     if (h.isCancelled())            // already cancelled
@@ -372,7 +369,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
                             SNode mn = m.next;
                             if (m.tryMatch(s)) {
                                 casHead(s, mn);     // pop both s and m
-                                return (mode == REQUEST)? m.item : s.item;
+                                return (mode == REQUEST) ? m.item : s.item;
                             } else                  // lost match
                                 s.casNext(m, mn);   // help unlink
                         }
@@ -423,11 +420,11 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
              * and don't wait at all, so are trapped in transfer
              * method rather than calling awaitFulfill.
              */
-            long lastTime = (timed)? System.nanoTime() : 0;
+            long lastTime = timed ? System.nanoTime() : 0;
             Thread w = Thread.currentThread();
             SNode h = head;
-            int spins = (shouldSpin(s)?
-                         (timed? maxTimedSpins : maxUntimedSpins) : 0);
+            int spins = (shouldSpin(s) ?
+                         (timed ? maxTimedSpins : maxUntimedSpins) : 0);
             for (;;) {
                 if (w.isInterrupted())
                     s.tryCancel();
@@ -444,7 +441,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
                     }
                 }
                 if (spins > 0)
-                    spins = shouldSpin(s)? (spins-1) : 0;
+                    spins = shouldSpin(s) ? (spins-1) : 0;
                 else if (s.waiter == null)
                     s.waiter = w; // establish waiter so can park next iter
                 else if (!timed)
@@ -499,6 +496,12 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
                     p = n;
             }
         }
+
+        // Unsafe mechanics
+        private static final sun.misc.Unsafe UNSAFE = sun.misc.Unsafe.getUnsafe();
+        private static final long headOffset =
+            objectFieldOffset(UNSAFE, "head", TransferStack.class);
+
     }
 
     /** Dual Queue */
@@ -524,29 +527,21 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
                 this.isData = isData;
             }
 
-            static final AtomicReferenceFieldUpdater<QNode, QNode>
-                nextUpdater = AtomicReferenceFieldUpdater.newUpdater
-                (QNode.class, QNode.class, "next");
-
             boolean casNext(QNode cmp, QNode val) {
-                return (next == cmp &&
-                        nextUpdater.compareAndSet(this, cmp, val));
+                return next == cmp &&
+                    UNSAFE.compareAndSwapObject(this, nextOffset, cmp, val);
             }
 
-            static final AtomicReferenceFieldUpdater<QNode, Object>
-                itemUpdater = AtomicReferenceFieldUpdater.newUpdater
-                (QNode.class, Object.class, "item");
-
             boolean casItem(Object cmp, Object val) {
-                return (item == cmp &&
-                        itemUpdater.compareAndSet(this, cmp, val));
+                return item == cmp &&
+                    UNSAFE.compareAndSwapObject(this, itemOffset, cmp, val);
             }
 
             /**
              * Tries to cancel by CAS'ing ref to this as item.
              */
             void tryCancel(Object cmp) {
-                itemUpdater.compareAndSet(this, cmp, this);
+                UNSAFE.compareAndSwapObject(this, itemOffset, cmp, this);
             }
 
             boolean isCancelled() {
@@ -561,6 +556,13 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
             boolean isOffList() {
                 return next == this;
             }
+
+            // Unsafe mechanics
+            private static final sun.misc.Unsafe UNSAFE = sun.misc.Unsafe.getUnsafe();
+            private static final long nextOffset =
+                objectFieldOffset(UNSAFE, "next", QNode.class);
+            private static final long itemOffset =
+                objectFieldOffset(UNSAFE, "item", QNode.class);
         }
 
         /** Head of queue */
@@ -580,41 +582,30 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
             tail = h;
         }
 
-        static final AtomicReferenceFieldUpdater<TransferQueue, QNode>
-            headUpdater = AtomicReferenceFieldUpdater.newUpdater
-            (TransferQueue.class,  QNode.class, "head");
-
         /**
          * Tries to cas nh as new head; if successful, unlink
          * old head's next node to avoid garbage retention.
          */
         void advanceHead(QNode h, QNode nh) {
-            if (h == head && headUpdater.compareAndSet(this, h, nh))
+            if (h == head &&
+                UNSAFE.compareAndSwapObject(this, headOffset, h, nh))
                 h.next = h; // forget old next
         }
 
-        static final AtomicReferenceFieldUpdater<TransferQueue, QNode>
-            tailUpdater = AtomicReferenceFieldUpdater.newUpdater
-            (TransferQueue.class, QNode.class, "tail");
-
         /**
          * Tries to cas nt as new tail.
          */
         void advanceTail(QNode t, QNode nt) {
             if (tail == t)
-                tailUpdater.compareAndSet(this, t, nt);
+                UNSAFE.compareAndSwapObject(this, tailOffset, t, nt);
         }
 
-        static final AtomicReferenceFieldUpdater<TransferQueue, QNode>
-            cleanMeUpdater = AtomicReferenceFieldUpdater.newUpdater
-            (TransferQueue.class, QNode.class, "cleanMe");
-
         /**
          * Tries to CAS cleanMe slot.
          */
         boolean casCleanMe(QNode cmp, QNode val) {
-            return (cleanMe == cmp &&
-                    cleanMeUpdater.compareAndSet(this, cmp, val));
+            return cleanMe == cmp &&
+                UNSAFE.compareAndSwapObject(this, cleanMeOffset, cmp, val);
         }
 
         /**
@@ -683,7 +674,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
                             s.item = s;
                         s.waiter = null;
                     }
-                    return (x != null)? x : e;
+                    return (x != null) ? x : e;
 
                 } else {                            // complementary-mode
                     QNode m = h.next;               // node to fulfill
@@ -700,7 +691,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
 
                     advanceHead(h, m);              // successfully fulfilled
                     LockSupport.unpark(m.waiter);
-                    return (x != null)? x : e;
+                    return (x != null) ? x : e;
                 }
             }
         }
@@ -716,10 +707,10 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
          */
         Object awaitFulfill(QNode s, Object e, boolean timed, long nanos) {
             /* Same idea as TransferStack.awaitFulfill */
-            long lastTime = (timed)? System.nanoTime() : 0;
+            long lastTime = timed ? System.nanoTime() : 0;
             Thread w = Thread.currentThread();
             int spins = ((head.next == s) ?
-                         (timed? maxTimedSpins : maxUntimedSpins) : 0);
+                         (timed ? maxTimedSpins : maxUntimedSpins) : 0);
             for (;;) {
                 if (w.isInterrupted())
                     s.tryCancel(e);
@@ -799,6 +790,16 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
                     return;          // Postpone cleaning s
             }
         }
+
+        // unsafe mechanics
+        private static final sun.misc.Unsafe UNSAFE = sun.misc.Unsafe.getUnsafe();
+        private static final long headOffset =
+            objectFieldOffset(UNSAFE, "head", TransferQueue.class);
+        private static final long tailOffset =
+            objectFieldOffset(UNSAFE, "tail", TransferQueue.class);
+        private static final long cleanMeOffset =
+            objectFieldOffset(UNSAFE, "cleanMe", TransferQueue.class);
+
     }
 
     /**
@@ -824,7 +825,7 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
      *        access; otherwise the order is unspecified.
      */
     public SynchronousQueue(boolean fair) {
-        transferer = (fair)? new TransferQueue() : new TransferStack();
+        transferer = fair ? new TransferQueue() : new TransferStack();
     }
 
     /**
@@ -1141,4 +1142,17 @@ public class SynchronousQueue<E> extends AbstractQueue<E>
             transferer = new TransferStack();
     }
 
+    // Unsafe mechanics
+    static long objectFieldOffset(sun.misc.Unsafe UNSAFE,
+                                  String field, Class<?> klazz) {
+        try {
+            return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));
+        } catch (NoSuchFieldException e) {
+            // Convert Exception to corresponding Error
+            NoSuchFieldError error = new NoSuchFieldError(field);
+            error.initCause(e);
+            throw error;
+        }
+    }
+
 }

src/share/classes/java/util/concurrent/ThreadPoolExecutor.java

@@ -1841,6 +1841,43 @@ public class ThreadPoolExecutor extends AbstractExecutorService {
         }
     }
 
+    /**
+     * Returns a string identifying this pool, as well as its state,
+     * including indications of run state and estimated worker and
+     * task counts.
+     *
+     * @return a string identifying this pool, as well as its state
+     */
+    public String toString() {
+        long ncompleted;
+        int nworkers, nactive;
+        final ReentrantLock mainLock = this.mainLock;
+        mainLock.lock();
+        try {
+            ncompleted = completedTaskCount;
+            nactive = 0;
+            nworkers = workers.size();
+            for (Worker w : workers) {
+                ncompleted += w.completedTasks;
+                if (w.isLocked())
+                    ++nactive;
+            }
+        } finally {
+            mainLock.unlock();
+        }
+        int c = ctl.get();
+        String rs = (runStateLessThan(c, SHUTDOWN) ? "Running" :
+                     (runStateAtLeast(c, TERMINATED) ? "Terminated" :
+                      "Shutting down"));
+        return super.toString() +
+            "[" + rs +
+            ", pool size = " + nworkers +
+            ", active threads = " + nactive +
+            ", queued tasks = " + workQueue.size() +
+            ", completed tasks = " + ncompleted +
+            "]";
+    }
+
     /* Extension hooks */
 
     /**
@@ -1961,7 +1998,9 @@ public class ThreadPoolExecutor extends AbstractExecutorService {
          * @throws RejectedExecutionException always.
          */
         public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
-            throw new RejectedExecutionException();
+            throw new RejectedExecutionException("Task " + r.toString() +
+                                                 " rejected from " +
+                                                 e.toString());
         }
     }
 

src/share/classes/java/util/concurrent/atomic/AtomicIntegerArray.java

@@ -48,28 +48,37 @@ import java.util.*;
 public class AtomicIntegerArray implements java.io.Serializable {
     private static final long serialVersionUID = 2862133569453604235L;
 
-   // setup to use Unsafe.compareAndSwapInt for updates
     private static final Unsafe unsafe = Unsafe.getUnsafe();
     private static final int base = unsafe.arrayBaseOffset(int[].class);
-    private static final int scale = unsafe.arrayIndexScale(int[].class);
+    private static final int shift;
     private final int[] array;
 
-    private long rawIndex(int i) {
+    static {
+        int scale = unsafe.arrayIndexScale(int[].class);
+        if ((scale & (scale - 1)) != 0)
+            throw new Error("data type scale not a power of two");
+        shift = 31 - Integer.numberOfLeadingZeros(scale);
+    }
+
+    private long checkedByteOffset(int i) {
         if (i < 0 || i >= array.length)
             throw new IndexOutOfBoundsException("index " + i);
-        return base + (long) i * scale;
+
+        return byteOffset(i);
+    }
+
+    private static long byteOffset(int i) {
+        return ((long) i << shift) + base;
     }
 
     /**
-     * Creates a new AtomicIntegerArray of given length.
+     * Creates a new AtomicIntegerArray of the given length, with all
+     * elements initially zero.
      *
      * @param length the length of the array
      */
     public AtomicIntegerArray(int length) {
         array = new int[length];
-        // must perform at least one volatile write to conform to JMM
-        if (length > 0)
-            unsafe.putIntVolatile(array, rawIndex(0), 0);
     }
 
     /**
@@ -80,17 +89,8 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * @throws NullPointerException if array is null
      */
     public AtomicIntegerArray(int[] array) {
-        if (array == null)
-            throw new NullPointerException();
-        int length = array.length;
-        this.array = new int[length];
-        if (length > 0) {
-            int last = length-1;
-            for (int i = 0; i < last; ++i)
-                this.array[i] = array[i];
-            // Do the last write as volatile
-            unsafe.putIntVolatile(this.array, rawIndex(last), array[last]);
-        }
+        // Visibility guaranteed by final field guarantees
+        this.array = array.clone();
     }
 
     /**
@@ -109,7 +109,11 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * @return the current value
      */
     public final int get(int i) {
-        return unsafe.getIntVolatile(array, rawIndex(i));
+        return getRaw(checkedByteOffset(i));
+    }
+
+    private int getRaw(long offset) {
+        return unsafe.getIntVolatile(array, offset);
     }
 
     /**
@@ -119,7 +123,7 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * @param newValue the new value
      */
     public final void set(int i, int newValue) {
-        unsafe.putIntVolatile(array, rawIndex(i), newValue);
+        unsafe.putIntVolatile(array, checkedByteOffset(i), newValue);
     }
 
     /**
@@ -130,7 +134,7 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * @since 1.6
      */
     public final void lazySet(int i, int newValue) {
-        unsafe.putOrderedInt(array, rawIndex(i), newValue);
+        unsafe.putOrderedInt(array, checkedByteOffset(i), newValue);
     }
 
     /**
@@ -142,9 +146,10 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * @return the previous value
      */
     public final int getAndSet(int i, int newValue) {
+        long offset = checkedByteOffset(i);
         while (true) {
-            int current = get(i);
-            if (compareAndSet(i, current, newValue))
+            int current = getRaw(offset);
+            if (compareAndSetRaw(offset, current, newValue))
                 return current;
         }
     }
@@ -160,8 +165,11 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * the actual value was not equal to the expected value.
      */
     public final boolean compareAndSet(int i, int expect, int update) {
-        return unsafe.compareAndSwapInt(array, rawIndex(i),
-                                        expect, update);
+        return compareAndSetRaw(checkedByteOffset(i), expect, update);
+    }
+
+    private boolean compareAndSetRaw(long offset, int expect, int update) {
+        return unsafe.compareAndSwapInt(array, offset, expect, update);
     }
 
     /**
@@ -188,12 +196,7 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * @return the previous value
      */
     public final int getAndIncrement(int i) {
-        while (true) {
-            int current = get(i);
-            int next = current + 1;
-            if (compareAndSet(i, current, next))
-                return current;
-        }
+        return getAndAdd(i, 1);
     }
 
     /**
@@ -203,12 +206,7 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * @return the previous value
      */
     public final int getAndDecrement(int i) {
-        while (true) {
-            int current = get(i);
-            int next = current - 1;
-            if (compareAndSet(i, current, next))
-                return current;
-        }
+        return getAndAdd(i, -1);
     }
 
     /**
@@ -219,10 +217,10 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * @return the previous value
      */
     public final int getAndAdd(int i, int delta) {
+        long offset = checkedByteOffset(i);
         while (true) {
-            int current = get(i);
-            int next = current + delta;
-            if (compareAndSet(i, current, next))
+            int current = getRaw(offset);
+            if (compareAndSetRaw(offset, current, current + delta))
                 return current;
         }
     }
@@ -234,12 +232,7 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * @return the updated value
      */
     public final int incrementAndGet(int i) {
-        while (true) {
-            int current = get(i);
-            int next = current + 1;
-            if (compareAndSet(i, current, next))
-                return next;
-        }
+        return addAndGet(i, 1);
     }
 
     /**
@@ -249,12 +242,7 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * @return the updated value
      */
     public final int decrementAndGet(int i) {
-        while (true) {
-            int current = get(i);
-            int next = current - 1;
-            if (compareAndSet(i, current, next))
-                return next;
-        }
+        return addAndGet(i, -1);
     }
 
     /**
@@ -265,22 +253,32 @@ public class AtomicIntegerArray implements java.io.Serializable {
      * @return the updated value
      */
     public final int addAndGet(int i, int delta) {
+        long offset = checkedByteOffset(i);
         while (true) {
-            int current = get(i);
+            int current = getRaw(offset);
             int next = current + delta;
-            if (compareAndSet(i, current, next))
+            if (compareAndSetRaw(offset, current, next))
                 return next;
         }
     }
 
     /**
      * Returns the String representation of the current values of array.
-     * @return the String representation of the current values of array.
+     * @return the String representation of the current values of array
      */
     public String toString() {
-        if (array.length > 0) // force volatile read
-            get(0);
-        return Arrays.toString(array);
+        int iMax = array.length - 1;
+        if (iMax == -1)
+            return "[]";
+
+        StringBuilder b = new StringBuilder();
+        b.append('[');
+        for (int i = 0; ; i++) {
+            b.append(getRaw(byteOffset(i)));
+            if (i == iMax)
+                return b.append(']').toString();
+            b.append(',').append(' ');
+        }
     }
 
 }

src/share/classes/java/util/concurrent/atomic/AtomicMarkableReference.java

@@ -38,8 +38,8 @@ package java.util.concurrent.atomic;
 /**
  * An {@code AtomicMarkableReference} maintains an object reference
  * along with a mark bit, that can be updated atomically.
- * <p>
- * <p> Implementation note. This implementation maintains markable
+ *
+ * <p>Implementation note: This implementation maintains markable
  * references by creating internal objects representing "boxed"
  * [reference, boolean] pairs.
  *
@@ -49,15 +49,19 @@ package java.util.concurrent.atomic;
  */
 public class AtomicMarkableReference<V> {
 
-    private static class ReferenceBooleanPair<T> {
-        private final T reference;
-        private final boolean bit;
-        ReferenceBooleanPair(T r, boolean i) {
-            reference = r; bit = i;
+    private static class Pair<T> {
+        final T reference;
+        final boolean mark;
+        private Pair(T reference, boolean mark) {
+            this.reference = reference;
+            this.mark = mark;
+        }
+        static <T> Pair<T> of(T reference, boolean mark) {
+            return new Pair<T>(reference, mark);
         }
     }
 
-    private final AtomicReference<ReferenceBooleanPair<V>>  atomicRef;
+    private volatile Pair<V> pair;
 
     /**
      * Creates a new {@code AtomicMarkableReference} with the given
@@ -67,7 +71,7 @@ public class AtomicMarkableReference<V>  {
      * @param initialMark the initial mark
      */
     public AtomicMarkableReference(V initialRef, boolean initialMark) {
-        atomicRef = new AtomicReference<ReferenceBooleanPair<V>> (new ReferenceBooleanPair<V>(initialRef, initialMark));
+        pair = Pair.of(initialRef, initialMark);
     }
 
     /**
@@ -76,7 +80,7 @@ public class AtomicMarkableReference<V>  {
      * @return the current value of the reference
      */
     public V getReference() {
-        return atomicRef.get().reference;
+        return pair.reference;
     }
 
     /**
@@ -85,7 +89,7 @@ public class AtomicMarkableReference<V>  {
      * @return the current value of the mark
      */
     public boolean isMarked() {
-        return atomicRef.get().bit;
+        return pair.mark;
     }
 
     /**
@@ -97,9 +101,9 @@ public class AtomicMarkableReference<V>  {
      * @return the current value of the reference
      */
     public V get(boolean[] markHolder) {
-        ReferenceBooleanPair<V> p = atomicRef.get();
-        markHolder[0] = p.bit;
-        return p.reference;
+        Pair<V> pair = this.pair;
+        markHolder[0] = pair.mark;
+        return pair.reference;
     }
 
     /**
@@ -122,13 +126,8 @@ public class AtomicMarkableReference<V>  {
                                      V       newReference,
                                      boolean expectedMark,
                                      boolean newMark) {
-        ReferenceBooleanPair<V> current = atomicRef.get();
-        return  expectedReference == current.reference &&
-            expectedMark == current.bit &&
-            ((newReference == current.reference && newMark == current.bit) ||
-             atomicRef.weakCompareAndSet(current,
-                                     new ReferenceBooleanPair<V>(newReference,
-                                                              newMark)));
+        return compareAndSet(expectedReference, newReference,
+                             expectedMark, newMark);
     }
 
     /**
@@ -147,13 +146,13 @@ public class AtomicMarkableReference<V>  {
                                  V       newReference,
                                  boolean expectedMark,
                                  boolean newMark) {
-        ReferenceBooleanPair<V> current = atomicRef.get();
-        return  expectedReference == current.reference &&
-            expectedMark == current.bit &&
-            ((newReference == current.reference && newMark == current.bit) ||
-             atomicRef.compareAndSet(current,
-                                     new ReferenceBooleanPair<V>(newReference,
-                                                              newMark)));
+        Pair<V> current = pair;
+        return
+            expectedReference == current.reference &&
+            expectedMark == current.mark &&
+            ((newReference == current.reference &&
+              newMark == current.mark) ||
+             casPair(current, Pair.of(newReference, newMark)));
     }
 
     /**
@@ -163,9 +162,9 @@ public class AtomicMarkableReference<V>  {
      * @param newMark the new value for the mark
      */
     public void set(V newReference, boolean newMark) {
-        ReferenceBooleanPair<V> current = atomicRef.get();
-        if (newReference != current.reference || newMark != current.bit)
-            atomicRef.set(new ReferenceBooleanPair<V>(newReference, newMark));
+        Pair<V> current = pair;
+        if (newReference != current.reference || newMark != current.mark)
+            this.pair = Pair.of(newReference, newMark);
     }
 
     /**
@@ -182,11 +181,32 @@ public class AtomicMarkableReference<V>  {
      * @return true if successful
      */
     public boolean attemptMark(V expectedReference, boolean newMark) {
-        ReferenceBooleanPair<V> current = atomicRef.get();
-        return  expectedReference == current.reference &&
-            (newMark == current.bit ||
-             atomicRef.compareAndSet
-             (current, new ReferenceBooleanPair<V>(expectedReference,
-                                                newMark)));
+        Pair<V> current = pair;
+        return
+            expectedReference == current.reference &&
+            (newMark == current.mark ||
+             casPair(current, Pair.of(expectedReference, newMark)));
+    }
+
+    // Unsafe mechanics
+
+    private static final sun.misc.Unsafe UNSAFE = sun.misc.Unsafe.getUnsafe();
+    private static final long pairOffset =
+        objectFieldOffset(UNSAFE, "pair", AtomicMarkableReference.class);
+
+    private boolean casPair(Pair<V> cmp, Pair<V> val) {
+        return UNSAFE.compareAndSwapObject(this, pairOffset, cmp, val);
+    }
+
+    static long objectFieldOffset(sun.misc.Unsafe UNSAFE,
+                                  String field, Class<?> klazz) {
+        try {
+            return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));
+        } catch (NoSuchFieldException e) {
+            // Convert Exception to corresponding Error
+            NoSuchFieldError error = new NoSuchFieldError(field);
+            error.initCause(e);
+            throw error;
+        }
     }
 }

test/ProblemList.txt

@@ -734,8 +734,8 @@ java/util/concurrent/locks/Lock/TimedAcquireLeak.java		generic-all
 # Fails on solaris-sparc -server (Set not equal to copy. 1)
 java/util/EnumSet/EnumSetBash.java			 	solaris-sparc
 
-# Need to be marked othervm, or changed to be samevm safe
-java/util/WeakHashMap/GCDuringIteration.java			generic-all
+# Fails on solaris-sparc, see 7011857
+java/util/concurrent/Phaser/FickleRegister.java			solaris-sparc
 
 ############################################################################
 

test/java/util/concurrent/ConcurrentQueues/IteratorWeakConsistency.java

@@ -53,7 +53,9 @@ public class IteratorWeakConsistency {
         test(new LinkedTransferQueue());
         // Other concurrent queues (e.g. ArrayBlockingQueue) do not
         // currently have weakly consistent iterators.
-        // test(new ArrayBlockingQueue(20));
+        // As of 2010-09, ArrayBlockingQueue passes this test, but
+        // does not fully implement weak consistency.
+        test(new ArrayBlockingQueue(20));
     }
 
     void test(Queue q) {

test/java/util/concurrent/Executors/AutoShutdown.java

@@ -24,6 +24,7 @@
 /*
  * @test
  * @bug 6399443
+ * @run main/othervm AutoShutdown
  * @summary Check for auto-shutdown and gc of singleThreadExecutors
  * @author Martin Buchholz
  */