On Wed, Feb 23, 2022 at 08:18:08PM +0100, Heiko Carstens wrote: > > The long term goal is to remove ZONE_DMA entirely at least for > > architectures that only use the small 16MB ISA-style one. It can > > then be replaced with for example a CMA area and fall into a movable > > zone. I'd have to prototype this first and see how it applies to the > > s390 case. It might not be worth it and maybe we should replace > > ZONE_DMA and ZONE_DMA32 with a ZONE_LIMITED for those use cases as > > the amount covered tends to not be totally out of line for what we > > built the zone infrastructure. > > So probably I'm missing something; but for small systems where we > would only have ZONE_DMA, how would a CMA area within this zone > improve things? It would not, but more importantly we would not need it at all. The thinking here is really about the nasty 16MB ISA-style zone DMA. a 31-bit something rather different.
