getting an error about: java.lang.OutOfMemoryError: Direct buffer memory

[Vytenis Silgalis]

kafka version - 0.9.0.0
JVM flags:
-Xmx1G -Xms1G -server -XX:+UseG1GC -XX:MaxGCPauseMillis=20
-XX:InitiatingHeapOccupancyPercent=35 -XX:+DisableExplicitGC
-Djava.awt.headless=true

It's not easily reproducible but has caused some issues for us, any insight
would be appreciated.

Full stack:
[2016-11-15 07:27:47,850] ERROR [Replica Manager on Broker 2]: Error
processing append operation on partition [fancy_topic_name,1]
(kafka.server.ReplicaManager)
java.lang.OutOfMemoryError: Direct buffer memory
        at java.nio.Bits.reserveMemory(Bits.java:631)
        at java.nio.DirectByteBuffer.<init>(DirectByteBuffer.java:123)
        at java.nio.ByteBuffer.allocateDirect(ByteBuffer.java:306)
        at sun.nio.ch.Util.getTemporaryDirectBuffer(Util.java:174)
        at sun.nio.ch.IOUtil.write(IOUtil.java:58)
        at sun.nio.ch.FileChannelImpl.write(FileChannelImpl.java:205)
        at
kafka.message.ByteBufferMessageSet.writeTo(ByteBufferMessageSet.scala:160)
        at kafka.log.FileMessageSet.append(FileMessageSet.scala:229)
        at kafka.log.LogSegment.append(LogSegment.scala:85)
        at kafka.log.Log.append(Log.scala:360)
        at kafka.cluster.Partition$$anonfun$9.apply(Partition.scala:442)
        at kafka.cluster.Partition$$anonfun$9.apply(Partition.scala:428)
        at kafka.utils.CoreUtils$.inLock(CoreUtils.scala:262)
        at kafka.utils.CoreUtils$.inReadLock(CoreUtils.scala:268)
        at
kafka.cluster.Partition.appendMessagesToLeader(Partition.scala:428)
        at
kafka.server.ReplicaManager$$anonfun$appendToLocalLog$2.apply(ReplicaManager.scala:401)
        at
kafka.server.ReplicaManager$$anonfun$appendToLocalLog$2.apply(ReplicaManager.scala:386)
        at
scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245)
        at
scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245)
        at
scala.collection.mutable.HashMap$$anonfun$foreach$1.apply(HashMap.scala:99)
        at
scala.collection.mutable.HashMap$$anonfun$foreach$1.apply(HashMap.scala:99)
        at
scala.collection.mutable.HashTable$class.foreachEntry(HashTable.scala:230)
        at scala.collection.mutable.HashMap.foreachEntry(HashMap.scala:40)
        at scala.collection.mutable.HashMap.foreach(HashMap.scala:99)
        at
scala.collection.TraversableLike$class.map(TraversableLike.scala:245)
        at scala.collection.AbstractTraversable.map(Traversable.scala:104)
        at
kafka.server.ReplicaManager.appendToLocalLog(ReplicaManager.scala:386)
        at
kafka.server.ReplicaManager.appendMessages(ReplicaManager.scala:322)
        at kafka.server.KafkaApis.handleProducerRequest(KafkaApis.scala:366)
        at kafka.server.KafkaApis.handle(KafkaApis.scala:68)
        at
kafka.server.KafkaRequestHandler.run(KafkaRequestHandler.scala:60)
        at java.lang.Thread.run(Thread.java:745)

Thanks,
Vytenis