Part 1 of this series, covered some background on ION, DMA-BUF heaps, the DMA API, and the concept of "ownership" when it comes to handling CPU-cache maintenance, finally ending on a conventional DMA API view of how DMA-BUF cache handling should be done. The article concluded with a discussion of why the traditional DMA APIs can perform poorly on contemporary systems. This article completes the series with an exploration of some of the approaches that DMA-BUF exporters can use to avoid unnecessary cache operations along with some rough proposals for how we might improve things.