From 7648fb539e8d3f2c582ec47bb0ac28929d236012 Mon Sep 17 00:00:00 2001
From: ashishk <ashishk@cloudera.com>
Date: Tue, 8 Apr 2025 16:03:44 +0530
Subject: [PATCH 1/2] HDDS-11856. Set StateMachine thread priority higher than
 CommandHandler thread.

---
 .../statemachine/DatanodeStateMachine.java    | 13 ++++++++++++
 .../common/TestDatanodeStateMachine.java      | 20 +++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/statemachine/DatanodeStateMachine.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/statemachine/DatanodeStateMachine.java
index e4d2050e4274..d08a10bebe93 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/statemachine/DatanodeStateMachine.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/statemachine/DatanodeStateMachine.java
@@ -555,6 +555,7 @@ public void startDaemon() {
           ExitUtils.terminate(1, message, ex, LOG);
         })
         .build().newThread(startStateMachineTask);
+    stateMachineThread.setPriority(Thread.MAX_PRIORITY);
     stateMachineThread.start();
   }
 
@@ -678,6 +679,7 @@ private void initCommandHandlerThread(ConfigurationSource config) {
 
     // We will have only one thread for command processing in a datanode.
     cmdProcessThread = getCommandHandlerThread(processCommandQueue);
+    cmdProcessThread.setPriority(Thread.NORM_PRIORITY);
     cmdProcessThread.start();
   }
 
@@ -745,4 +747,15 @@ public DatanodeQueueMetrics getQueueMetrics() {
   public ReconfigurationHandler getReconfigurationHandler() {
     return reconfigurationHandler;
   }
+
+  @VisibleForTesting
+  public Thread getStateMachineThread() {
+    return stateMachineThread;
+  }
+
+  @VisibleForTesting
+  public Thread getCmdProcessThread() {
+    return cmdProcessThread;
+  }
+
 }
diff --git a/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/TestDatanodeStateMachine.java b/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/TestDatanodeStateMachine.java
index 0ee12be72363..064e8424a9e5 100644
--- a/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/TestDatanodeStateMachine.java
+++ b/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/TestDatanodeStateMachine.java
@@ -404,6 +404,26 @@ public void testDatanodeStateMachineWithInvalidConfiguration()
     });
   }
 
+  @Test
+  public void testStateMachineThreadPriority() throws Exception {
+    DatanodeDetails datanodeDetails = getNewDatanodeDetails();
+    DatanodeDetails.Port port = DatanodeDetails.newStandalonePort(
+        OzoneConfigKeys.HDDS_CONTAINER_IPC_PORT_DEFAULT);
+    datanodeDetails.setPort(port);
+    try (DatanodeStateMachine stateMachine =
+             new DatanodeStateMachine(datanodeDetails, conf)) {
+      stateMachine.startDaemon();
+
+      // Wait for CmdProcessThread to initialize
+      GenericTestUtils.waitFor(()
+          ->  stateMachine.getCmdProcessThread() != null, 100, 3000);
+      Thread stateMachineThread = stateMachine.getStateMachineThread();
+      Thread cmdProcessThread = stateMachine.getCmdProcessThread();
+      // stateMachineThread priority is higher than cmdProcessThread
+      assertTrue(stateMachineThread.getPriority() > cmdProcessThread.getPriority());
+    }
+  }
+
   private DatanodeDetails getNewDatanodeDetails() {
     DatanodeDetails.Port containerPort = DatanodeDetails.newStandalonePort(0);
     DatanodeDetails.Port ratisPort = DatanodeDetails.newRatisPort(0);

From e8b9622941618ee74b64c586f3e87a32834545a1 Mon Sep 17 00:00:00 2001
From: ashishk <ashishk@cloudera.com>
Date: Thu, 10 Apr 2025 12:25:44 +0530
Subject: [PATCH 2/2] Fix review comment

---
 .../container/common/statemachine/DatanodeStateMachine.java     | 2 --
 1 file changed, 2 deletions(-)

diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/statemachine/DatanodeStateMachine.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/statemachine/DatanodeStateMachine.java
index d08a10bebe93..f10adecd0ffc 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/statemachine/DatanodeStateMachine.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/statemachine/DatanodeStateMachine.java
@@ -748,12 +748,10 @@ public ReconfigurationHandler getReconfigurationHandler() {
     return reconfigurationHandler;
   }
 
-  @VisibleForTesting
   public Thread getStateMachineThread() {
     return stateMachineThread;
   }
 
-  @VisibleForTesting
   public Thread getCmdProcessThread() {
     return cmdProcessThread;
   }