On Tuesday 14 June 2011 20:58:25 Zach Pfeffer wrote: > I've seen this split bank allocation in Qualcomm and TI SoCs, with > Samsung, that makes 3 major SoC vendors (I would be surprised if > Nvidia didn't also need to do this) - so I think some configurable > method to control allocations is necessarily. The chips can't do > decode without it (and by can't do I mean 1080P and higher decode is > not functionally useful). Far from special, this would appear to be > the default. Thanks for the insight, that's a much better argument than 'something may need it'. Are those all chips without an IOMMU or do we also need to solve the IOMMU case with split bank allocation? I think I'd still prefer to see the support for multiple regions split out into one of the later patches, especially since that would defer the question of how to do the initialization for this case and make sure we first get a generic way. You've convinced me that we need to solve the problem of allocating memory from a specific bank eventually, but separating it from the one at hand (contiguous allocation) should help getting the important groundwork in at first. The possible conflict that I still see with per-bank CMA regions are: * It completely destroys memory power management in cases where that is based on powering down entire memory banks. * We still need to solve the same problem in case of IOMMU mappings at some point, even if today's hardware doesn't have this combination. It would be good to use the same solution for both. Arnd -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>