NioServerSocketChannelFactory needs the maximum number of worker thre…

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Summary: The worker thread factory had enough maximum threads, but netty assumes number of cores * 2.  This is likely not adequate for our clusters.

Test Plan: Passed all corona unittests.

Reviewers: dms, rvadali, pyang

Reviewed By: rvadali

CC: mattwkelly

Task ID: 1152668

src/core/org/apache/hadoop/http/NettyMapOutputHttpServer.java

@@ -91,9 +91,11 @@ public synchronized void init(Configuration conf) {
     } catch (ClassCastException e) {
       LOG.warn("Netty worker thread pool is not of type ThreadPoolExecutor", e);
     }
+    LOG.info("Netty starting up with a maximum of " + maximumPoolSize +
+        " worker threads");
     channelFactory = new NioServerSocketChannelFactory(
         Executors.newCachedThreadPool(bossFactory),
-        workerThreadPool);
+        workerThreadPool, maximumPoolSize);
   }
 
   public synchronized int start(ChannelPipelineFactory pipelineFactory) {