CPU < -> GPU的消息队列

cuQU is a simple shared-memory queue for messaging between CPU and GPU, coded in CUDA. Working on proof-of-concept test program, I ended up coding a cuqu::queue template class, backed by a CPU pinned-memory area, used as a circular buffer, where: 1. The CPU is able to push() a chunk of data if space is available. 1. The GPU is able to retrive a chunk of data with a blocking and globally synchronizing pop() primitive. Main limitation is the GPU global synchronization[1], which imposes a limit on the grid of thread blocks, in such a way to avoid a deadlock. This is due to the NVidia scheduler not preempting the thread blocks. I thought it could be useful to a broader audience, so I"m committing it here under the Apache License 2.0, to be compatible with Thrust and the other wonderful libraries available in the CUDA ecosystem. I have a numbe