From 3b030731a066a06c8374327975771b60b7cfc6f0 Mon Sep 17 00:00:00 2001
From: Kihwal Lee <kihwal@apache.org>
Date: Thu, 29 Jan 2015 12:37:34 -0600
Subject: [PATCH] HDFS-7603. The background replication queue initialization
 may not let others run. Contributed by Kihwal Lee. (cherry picked from commit
 89b07490f8354bb83a67b7ffc917bfe99708e615)

---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt                  | 3 +++
 .../hadoop/hdfs/server/blockmanagement/BlockManager.java     | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 18b4fea06e2..efe7b492ccf 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -275,6 +275,9 @@ Release 2.7.0 - UNRELEASED
 
     HDFS-7675. Remove unused member DFSClient#spanReceiverHost (cmccabe)
 
+    HDFS-7603. The background replication queue initialization may not let
+    others run (kihwal)
+
   OPTIMIZATIONS
 
     HDFS-7454. Reduce memory footprint for AclEntries in NameNode.
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java
index 4ac04ec8c62..ec085d75896 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java
@@ -2615,6 +2615,9 @@ public class BlockManager {
     long totalBlocks = blocksMap.size();
     replicationQueuesInitProgress = 0;
     long totalProcessed = 0;
+    long sleepDuration =
+        Math.max(1, Math.min(numBlocksPerIteration/1000, 10000));
+
     while (namesystem.isRunning() && !Thread.currentThread().isInterrupted()) {
       int processed = 0;
       namesystem.writeLockInterruptibly();
@@ -2671,6 +2674,8 @@ public class BlockManager {
         }
       } finally {
         namesystem.writeUnlock();
+        // Make sure it is out of the write lock for sufficiently long time.
+        Thread.sleep(sleepDuration);
       }
     }
     if (Thread.currentThread().isInterrupted()) {