Make a separate uploader for long lived vs streaming data
Some SURFACE_STATEs we expect to live for a long time. Others are streamed out. We may want to make a separate u_upload_mgr for each kind of thing. That way, BOs containing data that has a sort life span will refcount to 0 at approximately the same time, while longer lived stuff will stick around together.
This may reduce the number of BOs used by batches, which reduces CPU overhead.