Spark数据本地性

putBlockInfo.synchronized {
      var marked = false
      try {
        if (level.useMemory) {
          // Save it just to memory first, even if it also has useDisk set to true; we will
          // drop it to disk later if the memory store can‘t hold it.
          val res = data match {
        ...
        }
          size = res.size
          res.data match {
            case Right(newBytes) => bytesAfterPut = newBytes
            case Left(newIterator) => valuesAfterPut = newIterator
          }
          // Keep track of which blocks are dropped from memory
          res.droppedBlocks.foreach { block => updatedBlocks += block }
        }
......