On 10/04/2017 04:54 AM, Michal Nazarewicz wrote: > On Tue, Oct 03 2017, Mike Kravetz wrote: >> At Plumbers this year, Guy Shattah and Christoph Lameter gave a presentation >> titled 'User space contiguous memory allocation for DMA' [1]. The slides >> point out the performance benefits of devices that can take advantage of >> larger physically contiguous areas. > > Issue I have is that kind of memory needed may depend on a device. Some > may require contiguous blocks. Some may support scatter-gather. Some > may be behind IO-MMU and not care either way. > > Furthermore, I feel déjà vu. Wasn’t dmabuf supposed to address this > issue? Thanks Michal, I was unaware of dmabuf and am just now looking at capabilities. The question is whether or not the IB driver writers requesting mmap(MAP_CONTIG) functionality could make use of dmabuf. That is out of my are of expertise, so I will let them reply. -- Mike Kravetz -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
