On Tue, Dec 20, 2016 at 11:33:27AM +0000, Chris Wilson wrote: > On Tue, Dec 20, 2016 at 11:13:43AM +0000, Tvrtko Ursulin wrote: > > How much is the cost of freeing and re-acquiring pages in the fall > > back case? It could be avoidable by using the table and adding > > something like sgt = i915_sg_copy(sgt, table_max_segment). But it > > depends on how likely is this path to be hit on swiotlb platforms. I > > have no idea. Our datasets are much bigger than the swiotlb space - > > if that is true on such platforms? > > It's below my level of care (atm). Platforms hitting this are using > swiotlb *bounce* buffers. They will not be able to support a full gfx > workload and be going through a copy. We could avoid the additional > work, the sg_table is large enough for a 1:1 copy if we do it before the > trim, but more importantly we need a simple fix for 4.10. Pushed this pair as I think this is the safe course of action. Creating i915_sg_expand() is a job for a rainy day. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
