Repository: spark Updated Branches: refs/heads/master 7c8d12322 -> 8867cd0bc
SPARK-1097: Do not introduce deadlock while fixing concurrency bug We recently added this lock on 'conf' in order to prevent concurrent creation. However, it turns out that this can introduce a deadlock because Hadoop also synchronizes on the Configuration objects when creating new Configurations (and they do so via a static REGISTRY which contains all created Configurations). This fix forces all Spark initialization of Configuration objects to occur serially by using a static lock that we control, and thus also prevents introducing the deadlock. Author: Aaron Davidson <aa...@databricks.com> Closes #1409 from aarondav/1054 and squashes the following commits: 7d1b769 [Aaron Davidson] SPARK-1097: Do not introduce deadlock while fixing concurrency bug Project: http://git-wip-us.apache.org/repos/asf/spark/repo Commit: http://git-wip-us.apache.org/repos/asf/spark/commit/8867cd0b Tree: http://git-wip-us.apache.org/repos/asf/spark/tree/8867cd0b Diff: http://git-wip-us.apache.org/repos/asf/spark/diff/8867cd0b Branch: refs/heads/master Commit: 8867cd0bc2961fefed84901b8b14e9676ae6ab18 Parents: 7c8d123 Author: Aaron Davidson <aa...@databricks.com> Authored: Wed Jul 16 14:10:17 2014 -0700 Committer: Patrick Wendell <pwend...@gmail.com> Committed: Wed Jul 16 14:10:17 2014 -0700 ---------------------------------------------------------------------- core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/spark/blob/8867cd0b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala ---------------------------------------------------------------------- diff --git a/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala index 0410285..e521612 100644 --- a/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala +++ b/core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala @@ -140,8 +140,8 @@ class HadoopRDD[K, V]( // Create a JobConf that will be cached and used across this RDD's getJobConf() calls in the // local process. The local cache is accessed through HadoopRDD.putCachedMetadata(). // The caching helps minimize GC, since a JobConf can contain ~10KB of temporary objects. - // synchronize to prevent ConcurrentModificationException (Spark-1097, Hadoop-10456) - conf.synchronized { + // Synchronize to prevent ConcurrentModificationException (Spark-1097, Hadoop-10456). + HadoopRDD.CONFIGURATION_INSTANTIATION_LOCK.synchronized { val newJobConf = new JobConf(conf) initLocalJobConfFuncOpt.map(f => f(newJobConf)) HadoopRDD.putCachedMetadata(jobConfCacheKey, newJobConf) @@ -246,6 +246,9 @@ class HadoopRDD[K, V]( } private[spark] object HadoopRDD { + /** Constructing Configuration objects is not threadsafe, use this lock to serialize. */ + val CONFIGURATION_INSTANTIATION_LOCK = new Object() + /** * The three methods below are helpers for accessing the local map, a property of the SparkEnv of * the local process.
