That's why the author says "theoretically" I guess ;) Yes in practice you probably wouldn't want your GPU compute engines to do such direct accesses and stall f

That's why the author says "theoretically" I guess ;) Yes in practice you probably wouldn't want your GPU compute engines to do such direct accesses and stall for a long time on each access, even for a one-shot streaming processing. Then even to avoid using the GPU main memory one would likely use DMA copies to a local working memory and do the processing there by chunks. But the direct mapping can still be convenient: a local DMA engine (or any HW coprocessor) can access host or GPU memory in the same way.