Merge pull request alteryx#169 from kayousterhout/mesos_fix

Don't ignore spark.cores.max when using Mesos Coarse mode

totalCoresAcquired is decremented but never incremented, causing Spark to effectively ignore spark.cores.max in coarse grained Mesos mode.

(cherry picked from commit 1a4cfbe)
Signed-off-by: Reynold Xin <[email protected]>

Author: rxin

core/src/main/scala/org/apache/spark/scheduler/cluster/mesos/CoarseMesosSchedulerBackend.scala

@@ -181,6 +181,7 @@ private[spark] class CoarseMesosSchedulerBackend(
             !slaveIdsWithExecutors.contains(slaveId)) {
           // Launch an executor on the slave
           val cpusToUse = math.min(cpus, maxCores - totalCoresAcquired)
+          totalCoresAcquired += cpusToUse
           val taskId = newMesosTaskId()
           taskIdToSlaveId(taskId) = slaveId
           slaveIdsWithExecutors += slaveId