better spruious wakeup handling and other simplifications

jetty · Mar 20, 2017 · 1a92015 · 1a92015
1 parent c01a910
commit 1a92015
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Showing 2 changed files with 71 additions and 54 deletions.
diff --git a/jetty-util/src/main/java/org/eclipse/jetty/util/BufferUtil.java b/jetty-util/src/main/java/org/eclipse/jetty/util/BufferUtil.java
@@ -420,11 +420,11 @@ public static int append(ByteBuffer to, ByteBuffer b)
     /* ------------------------------------------------------------ */
     /**
      * Like append, but does not throw {@link BufferOverflowException}
-     * @param to Buffer is flush mode
-     * @param b bytes to fill
-     * @param off offset into byte
+     * @param to Buffer The buffer to fill to. The buffer will be flipped to fill mode and then flipped back to flush mode.
+     * @param b bytes The bytes to fill
+     * @param off offset into bytes
      * @param len length to fill
-     * @return The position of the valid data before the flipped position.
+     * @return the number of bytes taken from the buffer.
      */
     public static int fill(ByteBuffer to, byte[] b, int off, int len)
     {

diff --git a/jetty-util/src/main/java/org/eclipse/jetty/util/thread/strategy/EatWhatYouKill.java b/jetty-util/src/main/java/org/eclipse/jetty/util/thread/strategy/EatWhatYouKill.java
@@ -147,75 +147,72 @@ public void run()
             LOG.debug("{} run", this);
         if (!isRunning())
             return;
-        boolean producing;
+        boolean producing = false;
         try (Lock locked = _locker.lock())
         {
             _pendingProducersDispatched--;
-            producing = pendingProducerWait();
-        }
+            _pendingProducers++;
 
-        if (producing)
-            produceConsume();
-    }
-
-    private boolean pendingProducerWait()
-    {
-        if (_pendingProducers<_pendingProducersMax)
-        {
-            try
+            loop: while (isRunning())
             {
-                _pendingProducers++;
-
-                _produce.await();
-                if (_pendingProducersSignalled==0)
-                {
-                    // spurious wakeup!
-                    if (LOG.isDebugEnabled() && isRunning())
-                        LOG.debug("{} SPURIOUS WAKEUP",this);
-                    _pendingProducers--;
-                } 
-                else
+                try
                 {
+                    _produce.await();
+
+                    if (_pendingProducersSignalled==0)
+                    {
+                        // spurious wakeup!
+                        continue loop;
+                    } 
+
                     _pendingProducersSignalled--;
                     if (_state == State.IDLE)                    
                     {
                         _state = State.PRODUCING;
-                        return true;
+                        producing = true;
                     } 
                 }
-            }
-            catch (InterruptedException e)
-            {
-                LOG.debug(e);
-                _pendingProducers--;
-            }
-        }       
-        return false;
+                catch (InterruptedException e)
+                {
+                    LOG.debug(e);
+                    _pendingProducers--;
+                }
+
+                break loop;
+            }     
+        }
+
+        if (producing)
+            produceConsume();
     }
 
     private void produceConsume()
     {
+        boolean may_block_caller = !Invocable.isNonBlockingInvocation();
         if (LOG.isDebugEnabled())
-            LOG.debug("{} produce enter", this);
+            LOG.debug("{} produce {}", this,may_block_caller?"non-blocking":"blocking");
 
         producing: while (isRunning())
         {
             // If we got here, then we are the thread that is producing.
-            if (LOG.isDebugEnabled())
-                LOG.debug("{} producing", this);
-
             Runnable task = _producer.produce();
 
-            if (LOG.isDebugEnabled())
-                LOG.debug("{} produced {}", this, task);
-
-            boolean may_block_caller = !Invocable.isNonBlockingInvocation();
             boolean new_pending_producer;
             boolean run_task_ourselves;
             boolean keep_producing;
 
+            StringBuilder state = null;
+
             try (Lock locked = _locker.lock())
             {
+                if (LOG.isDebugEnabled())
+                {
+                    state = new StringBuilder();
+                    getString(state);
+                    getState(state);
+                    state.append("->");
+                }
+
                 // Did we produced a task?
                 if (task == null)
                 {
@@ -261,9 +258,19 @@ else if (may_block_caller && (_pendingProducers>0 || _pendingProducersMax==0))
                     if (new_pending_producer)
                         _pendingProducersDispatched++;
                 }
+
+                if (LOG.isDebugEnabled())
+                    getState(state);
+
             }
+
             if (LOG.isDebugEnabled())
-                LOG.debug("{} mbc={} dnp={} run={} kp={}", this,may_block_caller,new_pending_producer,run_task_ourselves,keep_producing);
+            {
+                LOG.debug("{} {} {}",
+                    state,
+                    run_task_ourselves?(new_pending_producer?"EPC!":"PC"):"PEC",
+                    task);
+            }
 
             if (new_pending_producer)
                 // Spawn a new thread to continue production by running the produce loop.
@@ -316,21 +323,31 @@ protected void doStop() throws Exception
     public String toString()
     {
         StringBuilder builder = new StringBuilder();
+        getString(builder);
+        try (Lock locked = _locker.lock())
+        {
+            getState(builder);
+        }
+        return builder.toString();
+    }
+
+    private void getString(StringBuilder builder)
+    {
         builder.append(getClass().getSimpleName());
         builder.append('@');
         builder.append(Integer.toHexString(hashCode()));
         builder.append('/');
         builder.append(_producer);
         builder.append('/');
-        try (Lock locked = _locker.lock())
-        {
-            builder.append(_state);
-            builder.append('/');
-            builder.append(_pendingProducers);
-            builder.append('/');
-            builder.append(_pendingProducersMax);
-        }
-        return builder.toString();
+    }
+
+    private void getState(StringBuilder builder)
+    {
+        builder.append(_state);
+        builder.append('/');
+        builder.append(_pendingProducers);
+        builder.append('/');
+        builder.append(_pendingProducersMax);
     }
 
     private class RunProduce implements Runnable