[GitHub] anirudh2290 closed pull request #11216: Scala inference memory leak fix #11204

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anirudh2290 closed pull request #11216: Scala inference memory leak fix #11204
URL: https://github.com/apache/incubator-mxnet/pull/11216
 
 
   

This is a PR merged from a forked repository.
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diff --git a/scala-package/core/src/main/scala/org/apache/mxnet/FeedForward.scala b/scala-package/core/src/main/scala/org/apache/mxnet/FeedForward.scala
index 7289df19712..87c9bc72be0 100644
--- a/scala-package/core/src/main/scala/org/apache/mxnet/FeedForward.scala
+++ b/scala-package/core/src/main/scala/org/apache/mxnet/FeedForward.scala
@@ -224,13 +224,24 @@ class FeedForward private(
     var i = 0
     while (data.hasNext && i != numBatch) {
       val batch = data.next()
-      i += 1
-      ExecutorManager.loadData(batch, dataArrays)
-      predExec.forward(isTrain = false)
-      val padded = batch.pad
-      val realSize = batchSize - padded
-      for ((list, nd) <- outputs zip predExec.outputs) {
-        list += nd.slice(0, realSize).copy()
+      try {
+        i += 1
+        ExecutorManager.loadData(batch, dataArrays)
+        predExec.forward(isTrain = false)
+        val padded = batch.pad
+        val realSize = batchSize - padded
+        for ((list, nd) <- outputs zip predExec.outputs) {
+          // The slice is being written to a value so that dispose can be called after the copy.
+          // The one liner nd.slice().copy() leads to leaking the memory of the slice.
+          val ndSliced = nd.slice(0, realSize)
+          try {
+            list += ndSliced.copy()
+          } finally {
+            ndSliced.dispose()
+          }
+        }
+      } finally {
+        batch.dispose()
       }
     }
     // TODO(Yizhi): we can use Symbol.concat to do the same thing. Can it be more efficient?


 

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