From cdc3980221983a3247c9405831d5bd623b084681 Mon Sep 17 00:00:00 2001
From: Jesse Glick <jglick@cloudbees.com>
Date: Fri, 28 Mar 2014 14:31:29 -0400
Subject: [PATCH] Create a ViewJob.ReloadThread only if and when someone has a
 ViewJob to be reloaded.

---
 .../java/hudson/model/AbstractCIBase.java     |  2 +-
 core/src/main/java/hudson/model/ViewJob.java  | 46 ++++++++++++-------
 2 files changed, 30 insertions(+), 18 deletions(-)

diff --git a/core/src/main/java/hudson/model/AbstractCIBase.java b/core/src/main/java/hudson/model/AbstractCIBase.java
index 19cc8cfbf7..3d8f0858e4 100644
--- a/core/src/main/java/hudson/model/AbstractCIBase.java
+++ b/core/src/main/java/hudson/model/AbstractCIBase.java
@@ -81,7 +81,7 @@ public abstract class AbstractCIBase extends Node implements ItemGroup<TopLevelI
         v.owner = this;
     }
     protected void interruptReloadThread() {
-        ViewJob.reloadThread.interrupt();
+        ViewJob.interruptReloadThread();
     }
 
     protected void killComputer(Computer c) {
diff --git a/core/src/main/java/hudson/model/ViewJob.java b/core/src/main/java/hudson/model/ViewJob.java
index 7b74dbd959..c86abb33e7 100644
--- a/core/src/main/java/hudson/model/ViewJob.java
+++ b/core/src/main/java/hudson/model/ViewJob.java
@@ -23,18 +23,17 @@
  */
 package hudson.model;
 
-import jenkins.model.Jenkins;
-import org.kohsuke.stapler.StaplerRequest;
-import org.kohsuke.stapler.StaplerResponse;
-
-import javax.servlet.ServletException;
+import hudson.model.Descriptor.FormException;
 import java.io.IOException;
 import java.util.LinkedHashSet;
+import java.util.Set;
 import java.util.SortedMap;
-
-import hudson.model.Descriptor.FormException;
 import java.util.logging.Level;
 import java.util.logging.Logger;
+import javax.servlet.ServletException;
+import jenkins.model.Jenkins;
+import org.kohsuke.stapler.StaplerRequest;
+import org.kohsuke.stapler.StaplerResponse;
 
 /**
  * {@link Job} that monitors activities that happen outside Hudson,
@@ -69,16 +68,12 @@ public abstract class ViewJob<JobT extends ViewJob<JobT,RunT>, RunT extends Run<
      */
     private transient volatile boolean reloadingInProgress;
 
-    /**
-     * {@link ExternalJob}s that need to be reloaded.
-     *
-     * This is a set, so no {@link ExternalJob}s are scheduled twice, yet
-     * it's order is predictable, avoiding starvation.
-     */
-    private static final LinkedHashSet<ViewJob> reloadQueue = new LinkedHashSet<ViewJob>();
-    /*package*/ static final Thread reloadThread = new ReloadThread();
-    static {
-        reloadThread.start();
+    private static ReloadThread reloadThread;
+
+    static synchronized void interruptReloadThread() {
+        if (reloadThread != null) {
+            reloadThread.interrupt();
+        }
     }
 
     /**
@@ -120,6 +115,14 @@ public abstract class ViewJob<JobT extends ViewJob<JobT,RunT>, RunT extends Run<
                 // we don't want to block the current thread,
                 // so reloading is done asynchronously.
                 reloadingInProgress = true;
+                Set<ViewJob> reloadQueue;
+                synchronized (ViewJob.class) {
+                    if (reloadThread == null) {
+                        reloadThread = new ReloadThread();
+                        reloadThread.start();
+                    }
+                    reloadQueue = reloadThread.reloadQueue;
+                }
                 synchronized(reloadQueue) {
                     reloadQueue.add(this);
                     reloadQueue.notify();
@@ -164,6 +167,15 @@ public abstract class ViewJob<JobT extends ViewJob<JobT,RunT>, RunT extends Run<
      * Thread that reloads the {@link Run}s.
      */
     private static final class ReloadThread extends Thread {
+
+        /**
+         * {@link ExternalJob}s that need to be reloaded.
+         *
+         * This is a set, so no {@link ExternalJob}s are scheduled twice, yet
+         * it's order is predictable, avoiding starvation.
+         */
+        final Set<ViewJob> reloadQueue = new LinkedHashSet<ViewJob>();
+
         private ReloadThread() {
             setName("ViewJob reload thread");
         }
-- 
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