On Tue, Mar 19, 2019 at 12:05 PM Jerome Glisse <jglisse@xxxxxxxxxx> wrote: > > On Tue, Mar 19, 2019 at 11:42:00AM -0700, Dan Williams wrote: > > On Tue, Mar 19, 2019 at 10:45 AM Jerome Glisse <jglisse@xxxxxxxxxx> wrote: > > > > > > On Tue, Mar 19, 2019 at 10:33:57AM -0700, Dan Williams wrote: > > > > On Tue, Mar 19, 2019 at 10:19 AM Jerome Glisse <jglisse@xxxxxxxxxx> wrote: > > > > > > > > > > On Tue, Mar 19, 2019 at 10:12:49AM -0700, Andrew Morton wrote: > > > > > > On Tue, 19 Mar 2019 12:58:02 -0400 Jerome Glisse <jglisse@xxxxxxxxxx> wrote: > > > > [..] > > > > > > Also, the discussion regarding [07/10] is substantial and is ongoing so > > > > > > please let's push along wth that. > > > > > > > > > > I can move it as last patch in the serie but it is needed for ODP RDMA > > > > > convertion too. Otherwise i will just move that code into the ODP RDMA > > > > > code and will have to move it again into HMM code once i am done with > > > > > the nouveau changes and in the meantime i expect other driver will want > > > > > to use this 2 helpers too. > > > > > > > > I still hold out hope that we can find a way to have productive > > > > discussions about the implementation of this infrastructure. > > > > Threatening to move the code elsewhere to bypass the feedback is not > > > > productive. > > > > > > I am not threatening anything that code is in ODP _today_ with that > > > patchset i was factering it out so that i could also use it in nouveau. > > > nouveau is built in such way that right now i can not use it directly. > > > But i wanted to factor out now in hope that i can get the nouveau > > > changes in 5.2 and then convert nouveau in 5.3. > > > > > > So when i said that code will be in ODP it just means that instead of > > > removing it from ODP i will keep it there and it will just delay more > > > code sharing for everyone. > > > > The point I'm trying to make is that the code sharing for everyone is > > moving the implementation closer to canonical kernel code and use > > existing infrastructure. For example, I look at 'struct hmm_range' and > > see nothing hmm specific in it. I think we can make that generic and > > not build up more apis and data structures in the "hmm" namespace. > > Right now i am trying to unify driver for device that have can support > the mmu notifier approach through HMM. Unify to a superset of driver > that can not abide by mmu notifier is on my todo list like i said but > it comes after. I do not want to make the big jump in just one go. So > i doing thing under HMM and thus in HMM namespace, but once i tackle > the larger set i will move to generic namespace what make sense. > > This exact approach did happen several time already in the kernel. In > the GPU sub-system we did it several time. First do something for couple > devices that are very similar then grow to a bigger set of devices and > generalise along the way. > > So i do not see what is the problem of me repeating that same pattern > here again. Do something for a smaller set before tackling it on for > a bigger set. All of that is fine, but when I asked about the ultimate trajectory that replaces hmm_range_dma_map() with an updated / HMM-aware GUP implementation, the response was that hmm_range_dma_map() is here to stay. The issue is not with forking off a small side effort, it's the plan to absorb that capability into a common implementation across non-HMM drivers where possible.
