Quoting Tvrtko Ursulin (2021-01-21 11:00:25) > > On 20/01/2021 20:59, Chris Wilson wrote: > > Quoting Chris Wilson (2021-01-20 18:06:08) > >> Quoting Matthew Auld (2021-01-20 17:46:10) > >>> On Wed, 20 Jan 2021 at 15:40, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote: > >>>> > >>>> If we import a shmemfs object between devices, for example from > >>>> Tigerlake to DG1, we can simply reuse the native object and its backing > >>>> store. > >>> > >>> Hmmm interesting, so does that include re-using the actual sg mapping > >>> for the backing pages? Does that work out-of-the-box between different > >>> devices assuming we have iommu enabled? > >> > >> Indeed interesting; the dma_addr_t are supposed to be local to a device. > > > > On reflection, we are expected to use cross-device dma_addr_t with > > dma-buf. It's the exporter who assigns the dma_addr_t for the importer > > to use, and they are always given from the original device. > > > > Maybe not so bad. Definitely needs testing to see what happens in > > practice. > > What about object migration? I did not spot anything preventing it once > object was exported like this so owning device could move it to device > memory afterwards which would probably be bad. Depends on how you do your migration, but your migration should be checking that it is allowed to migrate the object first. -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
