From 89b07490f8354bb83a67b7ffc917bfe99708e615 Mon Sep 17 00:00:00 2001
From: Kihwal Lee <kihwal@apache.org>
Date: Thu, 29 Jan 2015 12:36:22 -0600
Subject: [PATCH] HDFS-7603. The background replication queue initialization
 may not let others run. Contributed by Kihwal Lee.

---
 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 4932c80dd1d..73f175f5851 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -561,6 +561,9 @@ 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 f240569898f..52bca48b09a 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
@@ -2612,6 +2612,9 @@ private void processMisReplicatesAsync() throws InterruptedException {
     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();
@@ -2668,6 +2671,8 @@ private void processMisReplicatesAsync() throws InterruptedException {
         }
       } finally {
         namesystem.writeUnlock();
+        // Make sure it is out of the write lock for sufficiently long time.
+        Thread.sleep(sleepDuration);
       }
     }
     if (Thread.currentThread().isInterrupted()) {