On 01/11/2017 09:52 AM, John Hubbard wrote: > Hi, > > I would like to attend this topic that Jerome has proposed. Studying the > kernel is a deep personal interest in addition to my career focus, and it > would be a rare privilege to work directly with some of you to converge > on some nice, clean designs for the kernel and these "new" > (page-fault-capable) devices that we have now. Here's what I can bring to > the discussion: > > a) An NVIDIA perspective on, and experience with, using the HMM patchset, > versions 1-15, at the device driver level. In addition to working on the > nvidia-uvm.ko driver (which handles CPU and GPU page faulting) since its > inception, I've also helped develop and maintain various facets of our GPU > device driver for Linux, for the last 9 years. > > As a semi-relevant aside, our company is allocating engineering time, > including mine, for long-term kernel projects such as this one. We want to > participate in maintaining and improving the kernel. I find that highly > encouraging and I hope others do, too. Times really are changing. > > b) Some thoughts about the dividing line between core kernel and drivers. > Our device drivers are starting to push the limits of what drivers should > really do (we are heading perhaps too deeply into memory management), and > of course I want to avoid going too far. For example, I've seen > recent comments on linux-mm that drivers shouldn't even take mmap_sem, > which is intriguing. We need to provide...something for that, though. > > c) Some thoughts about dealing with both HMM and ATS in the same driver > (our devices have to support both--although, not at the same time). > > -- > > For this discussion track, I'm especially interested in simultaneously > considering: > > 1. HMM (Jerome's Heterogeneous Memory Management patchset): this solves a > similar problem as ATS (Address Translation Services: unified CPU and > Device page tables), but without the need for specialized hardware. There > is a bit of overlap between the HMM and ATS+NUMA patchsets, as has been > discussed here before. > > 2. IBM's ATS+NUMA patchset. > > 3. Page-fault-capable devices in general. Initially thought there would be a single common discussion TOPIC for all of the "device memory management infrastructure" but seems like its getting split into multiple TOPICs. Hence I am trying to sign up for all them individually. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>