On Wed, Sep 6, 2017 at 3:36 AM, Jerome Glisse <jglisse@xxxxxxxxxx> wrote: > On Thu, Jul 20, 2017 at 08:48:20PM -0700, Dan Williams wrote: >> On Thu, Jul 20, 2017 at 6:41 PM, Jerome Glisse <jglisse@xxxxxxxxxx> wrote: >> > On Fri, Jul 21, 2017 at 09:15:29AM +0800, Bob Liu wrote: >> >> On 2017/7/20 23:03, Jerome Glisse wrote: >> >> > On Wed, Jul 19, 2017 at 05:09:04PM +0800, Bob Liu wrote: >> >> >> On 2017/7/19 10:25, Jerome Glisse wrote: >> >> >>> On Wed, Jul 19, 2017 at 09:46:10AM +0800, Bob Liu wrote: >> >> >>>> On 2017/7/18 23:38, Jerome Glisse wrote: >> >> >>>>> On Tue, Jul 18, 2017 at 11:26:51AM +0800, Bob Liu wrote: >> >> >>>>>> On 2017/7/14 5:15, Jérôme Glisse wrote: > > [...] > >> >> > Second device driver are not integrated that closely within mm and the >> >> > scheduler kernel code to allow to efficiently plug in device access >> >> > notification to page (ie to update struct page so that numa worker >> >> > thread can migrate memory base on accurate informations). >> >> > >> >> > Third it can be hard to decide who win between CPU and device access >> >> > when it comes to updating thing like last CPU id. >> >> > >> >> > Fourth there is no such thing like device id ie equivalent of CPU id. >> >> > If we were to add something the CPU id field in flags of struct page >> >> > would not be big enough so this can have repercusion on struct page >> >> > size. This is not an easy sell. >> >> > >> >> > They are other issues i can't think of right now. I think for now it >> >> >> >> My opinion is most of the issues are the same no matter use CDM or HMM-CDM. >> >> I just care about a more complete solution no matter CDM,HMM-CDM or other ways. >> >> HMM or HMM-CDM depends on device driver, but haven't see a public/full driver to >> >> demonstrate the whole solution works fine. >> > >> > I am working with NVidia close source driver team to make sure that it works >> > well for them. I am also working on nouveau open source driver for same NVidia >> > hardware thought it will be of less use as what is missing there is a solid >> > open source userspace to leverage this. Nonetheless open source driver are in >> > the work. >> >> Can you point to the nouveau patches? I still find these HMM patches >> un-reviewable without an upstream consumer. > > So i pushed a branch with WIP for nouveau to use HMM: > > https://cgit.freedesktop.org/~glisse/linux/log/?h=hmm-nouveau > Nice to see that. Btw, do you have any plan for a CDM-HMM driver? CPU can write to Device memory directly without extra copy. -- Thanks, Bob Liu > Top 16 patches are HMM related (implementic logic inside the driver to use > HMM). The next 16 patches are hardware specific patches and some nouveau > changes needed to allow page fault. > > It is enough to have simple malloc test case working: > > https://cgit.freedesktop.org/~glisse/compote > > There is 2 program here the old one is existing way you use GPU for compute > task while the new one is what HMM allow to achieve ie use malloc memory > directly. > > > I haven't added yet the device memory support it is in work and i will push > update to this branch and repo for that. Probably next week if no pressing > bug preempt my time. > > > So there is a lot of ugliness in all this and i don't expect this to be what > end up upstream. Right now there is a large rework of nouveau vm (virtual > memory) code happening to rework completely how we do address space management > within nouveau. This work is prerequisite for a clean implementation for HMM > inside nouveau (it will also lift the 40bits address space limitation that > exist today inside nouveau driver). Once that work land i will work on clean > upstreamable implementation for nouveau to use HMM as well as userspace to > leverage it (this is requirement for upstream GPU driver to have open source > userspace that make use of features). All this is a lot of work and there is > not many people working on this. > > > They are other initiatives under way related to this that i can not talk about > publicly but if they bare fruit they might help to speedup all this. > > Jérôme > -- 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
