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author | Aaron Davidson <aaron@databricks.com> | 2014-07-16 14:10:17 -0700 |
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committer | Patrick Wendell <pwendell@gmail.com> | 2014-07-16 14:10:17 -0700 |
commit | 8867cd0bc2961fefed84901b8b14e9676ae6ab18 (patch) | |
tree | 8abf9ad898a58b6dad65d4ec155c01ed622ec4f4 | |
parent | 7c8d123225bbdcc605642099b107c2d843e87340 (diff) | |
download | spark-8867cd0bc2961fefed84901b8b14e9676ae6ab18.tar.gz spark-8867cd0bc2961fefed84901b8b14e9676ae6ab18.tar.bz2 spark-8867cd0bc2961fefed84901b8b14e9676ae6ab18.zip |
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 <aaron@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
-rw-r--r-- | core/src/main/scala/org/apache/spark/rdd/HadoopRDD.scala | 7 |
1 files changed, 5 insertions, 2 deletions
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 0410285143..e521612ffc 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. |