Re: [PATCH 13/14] staging: android: ion: Do not sync CPU cache on map/unmap

[Laura Abbott]

On 1/24/19 8:44 AM, Brian Starkey wrote:
> On Thu, Jan 24, 2019 at 10:04:46AM -0600, Andrew F. Davis wrote:
> > On 1/23/19 11:11 AM, Brian Starkey wrote:
>
> [snip]
>
> > I'm very new to all this, so any pointers to history in this area are
> > appreciated.
>
> [snip]
>
> > > In case you didn't come across it already, the effort which seems to
> > > have gained the most "air-time" recently is
> > > https://github.com/cubanismo/allocator, which is still a userspace
> > > module (perhaps some concepts from there could go into the kernel?),
> > > but makes some attempts at generic constraint solving. It's also not
> > > really moving anywhere at the moment.
> >
> > Very interesting, I'm going to have to stare at this for a bit.
>
> In which case, some reading material that might be of interest :-)
>
> https://www.x.org/wiki/Events/XDC2016/Program/Unix_Device_Memory_Allocation.pdf
> https://www.x.org/wiki/Events/XDC2017/jones_allocator.pdf
> https://lists.freedesktop.org/archives/mesa-dev/2017-November/177632.html
>
> -Brian

In some respects this is more a question of "what is the purpose
of Ion". Once upon a time, Ion was going to do constraint solving
but that never really happened and I figured Ion would get deprecated.
People keep coming out of the woodwork with new uses for Ion so
its stuck around. This is why I've primarily focused on Ion as a
framework for exposing available memory types to userspace and leave
the constraint solving to someone else, since that's what most
users seem to want out of Ion ("I know I want memory type X please
give it to me"). That's not to say that this was a perfect or
even the correct approach, just what made the most sense based
on users.

Thanks,
Laura