On Tue, Mar 19, 2019 at 12:13:40PM -0700, Dan Williams wrote: > 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: [snip] > > > > 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. Just to get on the record in this thread. +1 I think having an interface which handles the MMU notifier stuff for drivers is awesome but we need to agree that the trajectory is to help more drivers if possible. Ira
