Hi Alyssa, > >>>> + /** >>>> + * @DRM_ASAHI_BIND_SINGLE_PAGE: Map a single page of the BO >>>> repeatedly >>>> + * across the VA range. >>>> + * >>>> + * This is useful to fill a VA range with scratch pages or zero >>>> pages. >>>> + * It is intended as a mechanism to accelerate sparse. >>>> + */ >>>> + DRM_ASAHI_BIND_SINGLE_PAGE = (1L << 2), >> >> Does this require the BO to be a single page? If so, does it require >> offset==0? Or does it just take whatever page is at the specified offset? > > I believe the intention is that it takes whatever page is at the > specified offset and just maps that a bunch of times. HK doesn't use > this yet though it probably should (this was added to help reduce > overhead when emulating sparse with scratch/zero pages, which is still > very new functionality in hk). > > Accelerating this properly involves GPUVM patches - although even without > that, moving the loop into the kernel so it's only a single ioctl > (user-kernel roundtrip) seems worth keeping the flag for.
FYI: I will be posting a patch for the GPUVM abstraction soon. — Daniel
