diff --git a/photon-api/src/main/scala/com/linkedin/photon/ml/SparkSessionConfiguration.scala b/photon-api/src/main/scala/com/linkedin/photon/ml/SparkSessionConfiguration.scala
index b8f1be57..d51a8d19 100644
--- a/photon-api/src/main/scala/com/linkedin/photon/ml/SparkSessionConfiguration.scala
+++ b/photon-api/src/main/scala/com/linkedin/photon/ml/SparkSessionConfiguration.scala
@@ -21,9 +21,9 @@ import org.apache.spark.serializer.KryoSerializer
 import org.apache.spark.sql.SparkSession
 import org.apache.spark.SparkConf
 
+import com.linkedin.photon.ml.aggregators._
 import com.linkedin.photon.ml.data.{GameDatum, LabeledPoint, LocalDataset}
 import com.linkedin.photon.ml.function._
-import com.linkedin.photon.ml.function.glm.{HessianVectorAggregator, ValueAndGradientAggregator}
 import com.linkedin.photon.ml.model.Coefficients
 import com.linkedin.photon.ml.normalization.NormalizationContext
 import com.linkedin.photon.ml.optimization._
@@ -52,6 +52,8 @@ object SparkSessionConfiguration {
     classOf[GeneralizedLinearModel],
     classOf[GeneralizedLinearOptimizationProblem[_]],
     classOf[GLMOptimizationConfiguration],
+    classOf[HessianDiagonalAggregator],
+    classOf[HessianMatrixAggregator],
     classOf[HessianVectorAggregator],
     classOf[LinearSubspaceProjector],
     classOf[LabeledPoint],
diff --git a/photon-api/src/main/scala/com/linkedin/photon/ml/function/DistributedObjectiveFunction.scala b/photon-api/src/main/scala/com/linkedin/photon/ml/function/DistributedObjectiveFunction.scala
index 78b5bcf2..42fe3ec5 100644
--- a/photon-api/src/main/scala/com/linkedin/photon/ml/function/DistributedObjectiveFunction.scala
+++ b/photon-api/src/main/scala/com/linkedin/photon/ml/function/DistributedObjectiveFunction.scala
@@ -17,8 +17,9 @@ package com.linkedin.photon.ml.function
 import breeze.linalg.{DenseMatrix, Vector}
 import org.apache.spark.rdd.RDD
 
+import com.linkedin.photon.ml.aggregators._
 import com.linkedin.photon.ml.data.LabeledPoint
-import com.linkedin.photon.ml.function.glm.{HessianDiagonalAggregator, HessianMatrixAggregator, HessianVectorAggregator, PointwiseLossFunction, ValueAndGradientAggregator}
+import com.linkedin.photon.ml.function.glm.PointwiseLossFunction
 import com.linkedin.photon.ml.model.{Coefficients => ModelCoefficients}
 import com.linkedin.photon.ml.normalization.NormalizationContext
 import com.linkedin.photon.ml.optimization.RegularizationType
diff --git a/photon-api/src/main/scala/com/linkedin/photon/ml/function/SingleNodeObjectiveFunction.scala b/photon-api/src/main/scala/com/linkedin/photon/ml/function/SingleNodeObjectiveFunction.scala
index 2433c2f8..5f88c992 100644
--- a/photon-api/src/main/scala/com/linkedin/photon/ml/function/SingleNodeObjectiveFunction.scala
+++ b/photon-api/src/main/scala/com/linkedin/photon/ml/function/SingleNodeObjectiveFunction.scala
@@ -16,8 +16,9 @@ package com.linkedin.photon.ml.function
 
 import breeze.linalg.{DenseMatrix, Vector}
 
+import com.linkedin.photon.ml.aggregators._
 import com.linkedin.photon.ml.data.LabeledPoint
-import com.linkedin.photon.ml.function.glm.{HessianDiagonalAggregator, HessianMatrixAggregator, HessianVectorAggregator, PointwiseLossFunction, ValueAndGradientAggregator}
+import com.linkedin.photon.ml.function.glm.PointwiseLossFunction
 import com.linkedin.photon.ml.model.{Coefficients => ModelCoefficients}
 import com.linkedin.photon.ml.normalization.NormalizationContext
 import com.linkedin.photon.ml.optimization.RegularizationType
diff --git a/photon-lib/src/main/scala/com/linkedin/photon/ml/function/glm/HessianDiagonalAggregator.scala b/photon-lib/src/main/scala/com/linkedin/photon/ml/aggregators/HessianDiagonalAggregator.scala
similarity index 98%
rename from photon-lib/src/main/scala/com/linkedin/photon/ml/function/glm/HessianDiagonalAggregator.scala
rename to photon-lib/src/main/scala/com/linkedin/photon/ml/aggregators/HessianDiagonalAggregator.scala
index 0d7767f9..71225864 100644
--- a/photon-lib/src/main/scala/com/linkedin/photon/ml/function/glm/HessianDiagonalAggregator.scala
+++ b/photon-lib/src/main/scala/com/linkedin/photon/ml/aggregators/HessianDiagonalAggregator.scala
@@ -12,12 +12,13 @@
  * License for the specific language governing permissions and limitations
  * under the License.
  */
-package com.linkedin.photon.ml.function.glm
+package com.linkedin.photon.ml.aggregators
 
 import breeze.linalg._
 import org.apache.spark.rdd.RDD
 
 import com.linkedin.photon.ml.data.LabeledPoint
+import com.linkedin.photon.ml.function.glm.PointwiseLossFunction
 import com.linkedin.photon.ml.util.{BroadcastWrapper, PhotonBroadcast, PhotonNonBroadcast}
 
 /**
diff --git a/photon-lib/src/main/scala/com/linkedin/photon/ml/function/glm/HessianMatrixAggregator.scala b/photon-lib/src/main/scala/com/linkedin/photon/ml/aggregators/HessianMatrixAggregator.scala
similarity index 98%
rename from photon-lib/src/main/scala/com/linkedin/photon/ml/function/glm/HessianMatrixAggregator.scala
rename to photon-lib/src/main/scala/com/linkedin/photon/ml/aggregators/HessianMatrixAggregator.scala
index 16eb1f49..0f9ac06c 100644
--- a/photon-lib/src/main/scala/com/linkedin/photon/ml/function/glm/HessianMatrixAggregator.scala
+++ b/photon-lib/src/main/scala/com/linkedin/photon/ml/aggregators/HessianMatrixAggregator.scala
@@ -12,12 +12,13 @@
  * License for the specific language governing permissions and limitations
  * under the License.
  */
-package com.linkedin.photon.ml.function.glm
+package com.linkedin.photon.ml.aggregators
 
 import breeze.linalg._
 import org.apache.spark.rdd.RDD
 
 import com.linkedin.photon.ml.data.LabeledPoint
+import com.linkedin.photon.ml.function.glm.PointwiseLossFunction
 import com.linkedin.photon.ml.util.{BroadcastWrapper, PhotonBroadcast, PhotonNonBroadcast}
 
 /**
diff --git a/photon-lib/src/main/scala/com/linkedin/photon/ml/function/glm/HessianVectorAggregator.scala b/photon-lib/src/main/scala/com/linkedin/photon/ml/aggregators/HessianVectorAggregator.scala
similarity index 98%
rename from photon-lib/src/main/scala/com/linkedin/photon/ml/function/glm/HessianVectorAggregator.scala
rename to photon-lib/src/main/scala/com/linkedin/photon/ml/aggregators/HessianVectorAggregator.scala
index 4038541d..2464ad5f 100644
--- a/photon-lib/src/main/scala/com/linkedin/photon/ml/function/glm/HessianVectorAggregator.scala
+++ b/photon-lib/src/main/scala/com/linkedin/photon/ml/aggregators/HessianVectorAggregator.scala
@@ -12,12 +12,13 @@
  * License for the specific language governing permissions and limitations
  * under the License.
  */
-package com.linkedin.photon.ml.function.glm
+package com.linkedin.photon.ml.aggregators
 
 import breeze.linalg.{Vector, axpy}
 import org.apache.spark.rdd.RDD
 
 import com.linkedin.photon.ml.data.LabeledPoint
+import com.linkedin.photon.ml.function.glm.PointwiseLossFunction
 import com.linkedin.photon.ml.normalization.NormalizationContext
 import com.linkedin.photon.ml.util.{BroadcastWrapper, PhotonBroadcast, PhotonNonBroadcast}
 
diff --git a/photon-lib/src/main/scala/com/linkedin/photon/ml/function/glm/ValueAndGradientAggregator.scala b/photon-lib/src/main/scala/com/linkedin/photon/ml/aggregators/ValueAndGradientAggregator.scala
similarity index 99%
rename from photon-lib/src/main/scala/com/linkedin/photon/ml/function/glm/ValueAndGradientAggregator.scala
rename to photon-lib/src/main/scala/com/linkedin/photon/ml/aggregators/ValueAndGradientAggregator.scala
index b8344d26..4166f44e 100644
--- a/photon-lib/src/main/scala/com/linkedin/photon/ml/function/glm/ValueAndGradientAggregator.scala
+++ b/photon-lib/src/main/scala/com/linkedin/photon/ml/aggregators/ValueAndGradientAggregator.scala
@@ -12,12 +12,13 @@
  * License for the specific language governing permissions and limitations
  * under the License.
  */
-package com.linkedin.photon.ml.function.glm
+package com.linkedin.photon.ml.aggregators
 
 import breeze.linalg.{DenseVector, Vector, axpy}
 import org.apache.spark.rdd.RDD
 
 import com.linkedin.photon.ml.data.LabeledPoint
+import com.linkedin.photon.ml.function.glm.PointwiseLossFunction
 import com.linkedin.photon.ml.normalization.NormalizationContext
 import com.linkedin.photon.ml.util.{BroadcastWrapper, PhotonBroadcast, PhotonNonBroadcast}