HDFS-16500. Make asynchronous blocks deletion lock and unlock durtion threshold configurable. (#4061). Contributed by Chengwei Wang.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java

@@ -481,6 +481,17 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
       "dfs.namenode.block.deletion.increment";
   public static final int DFS_NAMENODE_BLOCK_DELETION_INCREMENT_DEFAULT = 1000;
 
+  /** The limit of single lock holding duration.*/
+  public static final String DFS_NAMENODE_BLOCK_DELETION_LOCK_THRESHOLD_MS =
+      "dfs.namenode.block.deletion.lock.threshold.ms";
+  public static final int DFS_NAMENODE_BLOCK_DELETION_LOCK_THRESHOLD_MS_DEFAULT =
+      50;
+  /** The sleep interval for releasing lock.*/
+  public static final String DFS_NAMENODE_BLOCK_DELETION_UNLOCK_INTERVAL_MS =
+      "dfs.namenode.block.deletion.unlock.interval.ms";
+  public static final int DFS_NAMENODE_BLOCK_DELETION_UNLOCK_INTERVAL_MS_DEFAULT =
+      10;
+
   public static final String DFS_NAMENODE_SNAPSHOT_CAPTURE_OPENFILES =
       HdfsClientConfigKeys.DFS_NAMENODE_SNAPSHOT_CAPTURE_OPENFILES;
   public static final boolean DFS_NAMENODE_SNAPSHOT_CAPTURE_OPENFILES_DEFAULT =

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java

@@ -192,8 +192,8 @@ public class BlockManager implements BlockStatsMXBean {
   private volatile long lowRedundancyBlocksCount = 0L;
   private volatile long scheduledReplicationBlocksCount = 0L;
 
-  private final long deleteBlockLockTimeMs = 500;
-  private final long deleteBlockUnlockIntervalTimeMs = 100;
+  private final long deleteBlockLockTimeMs;
+  private final long deleteBlockUnlockIntervalTimeMs;
 
   /** flag indicating whether replication queues have been initialized */
   private boolean initializedReplQueues;
@@ -495,6 +495,12 @@ public class BlockManager implements BlockStatsMXBean {
     startupDelayBlockDeletionInMs = conf.getLong(
         DFSConfigKeys.DFS_NAMENODE_STARTUP_DELAY_BLOCK_DELETION_SEC_KEY,
         DFSConfigKeys.DFS_NAMENODE_STARTUP_DELAY_BLOCK_DELETION_SEC_DEFAULT) * 1000L;
+    deleteBlockLockTimeMs = conf.getLong(
+        DFSConfigKeys.DFS_NAMENODE_BLOCK_DELETION_LOCK_THRESHOLD_MS,
+        DFSConfigKeys.DFS_NAMENODE_BLOCK_DELETION_LOCK_THRESHOLD_MS_DEFAULT);
+    deleteBlockUnlockIntervalTimeMs = conf.getLong(
+        DFSConfigKeys.DFS_NAMENODE_BLOCK_DELETION_UNLOCK_INTERVAL_MS,
+        DFSConfigKeys.DFS_NAMENODE_BLOCK_DELETION_UNLOCK_INTERVAL_MS_DEFAULT);
     invalidateBlocks = new InvalidateBlocks(
         datanodeManager.getBlockInvalidateLimit(),
         startupDelayBlockDeletionInMs,

hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml

@@ -6136,6 +6136,25 @@
     </description>
   </property>
 
+  <property>
+    <name>dfs.namenode.block.deletion.lock.threshold.ms</name>
+    <value>50</value>
+    <description>
+      The limit of single time lock holding duration for the block asynchronous
+      deletion thread.
+    </description>
+  </property>
+
+  <property>
+    <name>dfs.namenode.block.deletion.unlock.interval.ms</name>
+    <value>10</value>
+    <description>
+      The sleep interval for yield lock.
+      When the single time lock holding duration of the block asynchronous deletion
+      thread exceeds limit, sleeping to yield lock.
+    </description>
+  </property>
+
   <property>
     <name>dfs.namenode.rpc-address.auxiliary-ports</name>
     <value></value>