[SPARK-7392] [CORE] bugfix: Kryo buffer size cannot be larger than 2M

Author: Zhang, Liye <liye.zhang@intel.com>

Closes apache#5934 from liyezhang556520/kryoBufSize and squashes the following commits:

5707e04 [Zhang, Liye] fix import order
8693288 [Zhang, Liye] replace multiplier with ByteUnit methods
9bf93e9 [Zhang, Liye] add tests
d91e5ed [Zhang, Liye] change kb to mb

core/src/main/scala/org/apache/spark/serializer/KryoSerializer.scala

@@ -32,6 +32,7 @@ import org.apache.spark._
 import org.apache.spark.api.python.PythonBroadcast
 import org.apache.spark.broadcast.HttpBroadcast
 import org.apache.spark.network.nio.{GetBlock, GotBlock, PutBlock}
+import org.apache.spark.network.util.ByteUnit
 import org.apache.spark.scheduler.{CompressedMapStatus, HighlyCompressedMapStatus}
 import org.apache.spark.storage._
 import org.apache.spark.util.BoundedPriorityQueue
@@ -51,18 +52,18 @@ class KryoSerializer(conf: SparkConf)
 
   private val bufferSizeKb = conf.getSizeAsKb("spark.kryoserializer.buffer", "64k")
 
-  if (bufferSizeKb >= 2048) {
+  if (bufferSizeKb >= ByteUnit.GiB.toKiB(2)) {
     throw new IllegalArgumentException("spark.kryoserializer.buffer must be less than " +
-      s"2048 mb, got: + $bufferSizeKb mb.")
+      s"2048 mb, got: + ${ByteUnit.KiB.toMiB(bufferSizeKb)} mb.")
   }
-  private val bufferSize = (bufferSizeKb * 1024).toInt
+  private val bufferSize = ByteUnit.KiB.toBytes(bufferSizeKb).toInt
 
   val maxBufferSizeMb = conf.getSizeAsMb("spark.kryoserializer.buffer.max", "64m").toInt
-  if (maxBufferSizeMb >= 2048) {
+  if (maxBufferSizeMb >= ByteUnit.GiB.toMiB(2)) {
     throw new IllegalArgumentException("spark.kryoserializer.buffer.max must be less than " +
       s"2048 mb, got: + $maxBufferSizeMb mb.")
   }
-  private val maxBufferSize = maxBufferSizeMb * 1024 * 1024
+  private val maxBufferSize = ByteUnit.MiB.toBytes(maxBufferSizeMb).toInt
 
   private val referenceTracking = conf.getBoolean("spark.kryo.referenceTracking", true)
   private val registrationRequired = conf.getBoolean("spark.kryo.registrationRequired", false)

core/src/test/scala/org/apache/spark/serializer/KryoSerializerSuite.scala

@@ -32,6 +32,36 @@ class KryoSerializerSuite extends FunSuite with SharedSparkContext {
   conf.set("spark.serializer", "org.apache.spark.serializer.KryoSerializer")
   conf.set("spark.kryo.registrator", classOf[MyRegistrator].getName)
 
+  test("configuration limits") {
+    val conf1 = conf.clone()
+    val kryoBufferProperty = "spark.kryoserializer.buffer"
+    val kryoBufferMaxProperty = "spark.kryoserializer.buffer.max"
+    conf1.set(kryoBufferProperty, "64k")
+    conf1.set(kryoBufferMaxProperty, "64m")
+    new KryoSerializer(conf1).newInstance()
+    // 2048m = 2097152k
+    conf1.set(kryoBufferProperty, "2097151k")
+    conf1.set(kryoBufferMaxProperty, "64m")
+    // should not throw exception when kryoBufferMaxProperty < kryoBufferProperty
+    new KryoSerializer(conf1).newInstance()
+    conf1.set(kryoBufferMaxProperty, "2097151k")
+    new KryoSerializer(conf1).newInstance()
+    val conf2 = conf.clone()
+    conf2.set(kryoBufferProperty, "2048m")
+    val thrown1 = intercept[IllegalArgumentException](new KryoSerializer(conf2).newInstance())
+    assert(thrown1.getMessage.contains(kryoBufferProperty))
+    val conf3 = conf.clone()
+    conf3.set(kryoBufferMaxProperty, "2048m")
+    val thrown2 = intercept[IllegalArgumentException](new KryoSerializer(conf3).newInstance())
+    assert(thrown2.getMessage.contains(kryoBufferMaxProperty))
+    val conf4 = conf.clone()
+    conf4.set(kryoBufferProperty, "2g")
+    conf4.set(kryoBufferMaxProperty, "3g")
+    val thrown3 = intercept[IllegalArgumentException](new KryoSerializer(conf4).newInstance())
+    assert(thrown3.getMessage.contains(kryoBufferProperty))
+    assert(!thrown3.getMessage.contains(kryoBufferMaxProperty))
+  }
+
   test("basic types") {
     val ser = new KryoSerializer(conf).newInstance()
     def check[T: ClassTag](t: T) {