On Mon, May 07, 2018 at 12:19:01AM +0300, Dmitry Osipenko wrote: > Probably the best variant would be to give an explicit control over syncing to a > user of the IOMMU API, like for example device driver may perform multiple > mappings / unmappings and then sync/flush in the end. I'm not sure that it's > really worth the hassle to shuffle the API right now, maybe we can implement it > later if needed. Joerg, do you have objections to a 'compound page' approach? Have you measured the performance difference on both variants? The compound-page approach only works for cases when the physical memory you map contiguous and correctly aligned. If it is really needed I would prefer a separate iotlb_sync_map() call-back that is just NULL when not needed. This way all users that don't need it only get a minimal penalty in the mapping path and you don't have any requirements on the physical memory you map to get good performance. Joerg -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
