[BUG] Fix reserve slots failed due to take buffer stuck (#283)

* [BUG] Fix reserve slots failed due to take buffer stuck

server-worker/src/main/java/com/aliyun/emr/rss/service/deploy/worker/FileWriter.java

@@ -317,7 +317,7 @@ private void takeBuffer() {
     }
 
     // real action
-    flushBuffer = flusher.takeBuffer(timeoutMs, flushWorkerIndex);
+    flushBuffer = flusher.takeBuffer(timeoutMs);
 
     // metrics end
     if (source.samplePerfCritical()) {
@@ -341,7 +341,7 @@ private void addTask(FlushTask task) throws IOException {
 
   private synchronized void returnBuffer() {
     if (flushBuffer != null) {
-      flusher.returnBuffer(flushBuffer, flushWorkerIndex);
+      flusher.returnBuffer(flushBuffer);
       flushBuffer = null;
     }
   }

server-worker/src/main/scala/com/aliyun/emr/rss/service/deploy/worker/LocalStorageManager.scala

@@ -54,7 +54,7 @@ private[worker] final class DiskFlusher(
   val threadCount: Int) extends DeviceObserver with Logging {
   private lazy val diskFlusherId = System.identityHashCode(this)
   private val workingQueues = new Array[LinkedBlockingQueue[FlushTask]](threadCount)
-  private val bufferQueues = new Array[LinkedBlockingQueue[CompositeByteBuf]](threadCount)
+  private val bufferQueue = new LinkedBlockingQueue[CompositeByteBuf](queueCapacity)
   private val workers = new Array[Thread](threadCount)
   private val nextWorkerIndex = new AtomicInteger()
 
@@ -68,14 +68,11 @@ private[worker] final class DiskFlusher(
   init()
 
   private def init(): Unit = {
-    val actualQueueSize = queueCapacity / threadCount + 1
+    for (_ <- 0 until queueCapacity) {
+      bufferQueue.put(Unpooled.compositeBuffer(256))
+    }
     for (index <- 0 until (threadCount)) {
-      workingQueues(index) = new LinkedBlockingQueue[FlushTask](actualQueueSize)
-      bufferQueues(index) = new LinkedBlockingQueue[CompositeByteBuf](actualQueueSize)
-      for (_ <- 0 until actualQueueSize) {
-        bufferQueues(index).put(Unpooled.compositeBuffer(256))
-      }
-
+      workingQueues(index) = new LinkedBlockingQueue[FlushTask](queueCapacity)
       workers(index) = new Thread(s"$this-$index") {
         override def run(): Unit = {
           while (!stopFlag.get()) {
@@ -96,7 +93,7 @@ private[worker] final class DiskFlusher(
                 }
                 lastBeginFlushTime = -1
               }
-              returnBuffer(task.buffer, index)
+              returnBuffer(task.buffer)
               task.notifier.numPendingFlushes.decrementAndGet()
             }
           }
@@ -122,16 +119,16 @@ private[worker] final class DiskFlusher(
     nextIndex % threadCount
   }
 
-  def takeBuffer(timeoutMs: Long, workerIndex: Int): CompositeByteBuf = {
-    bufferQueues(workerIndex).poll(timeoutMs, TimeUnit.MILLISECONDS)
+  def takeBuffer(timeoutMs: Long): CompositeByteBuf = {
+    bufferQueue.poll(timeoutMs, TimeUnit.MILLISECONDS)
   }
 
-  def returnBuffer(buffer: CompositeByteBuf, workerIndex: Int): Unit = {
+  def returnBuffer(buffer: CompositeByteBuf): Unit = {
     MemoryTracker.instance().releaseDiskBuffer(buffer.readableBytes())
     buffer.removeComponents(0, buffer.numComponents())
     buffer.clear()
 
-    bufferQueues(workerIndex).put(buffer)
+    bufferQueue.put(buffer)
   }
 
   def addTask(task: FlushTask, timeoutMs: Long, workerIndex: Int): Boolean = {
@@ -162,7 +159,7 @@ private[worker] final class DiskFlusher(
     deviceMonitor.reportDeviceError(workingDir, e, deviceErrorType)
   }
 
-  def bufferQueueInfo(): String = s"$this used buffers: ${bufferQueues.map(_.size()).toList}"
+  def bufferQueueInfo(): String = s"$this used buffers: ${bufferQueue.size()}"
 
   override def hashCode(): Int = {
     workingDir.hashCode()