On Monday 23 March 2015, Benjamin Herrenschmidt wrote: > On Mon, 2015-03-23 at 07:04 +0100, Arnd Bergmann wrote: > > > > My guess is that the ARM code so far has been concerned mainly with > > getting things to work in the first place, but scalability problems > > will only be seen when there are faster CPU cores become available. > > In any case, I think this is mostly a non-issue. The complexity of the > ARM code is in various areas related to making shit work (handling > coherent allocations mostly) but only remotely related to the actual > iommu DMA space allocator (iova in ARM as far as I understand the code) > which is pretty standard. Ok, got it. Thanks for explaining tht part. > The work Sowmini is doing is about specifically the allocator. Making > our (powerpc) allocator generic since it has some nice scalability > features. > > In fact, what Aik and I have been pushing and Sowmini is close to > achieving is to mostly disconnect that allocator from the rest of the > iommu management (the caller). > > So in the end, the allocator itself should be splitable into something > separate that resides in lib/ or similar, which ARM can chose to use as > well. Yes, this sounds like a good idea. I'm currently at ELC and will bring this up with the people working on ARM IOMMU support. Arnd -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
