Re: Data transfers from/to client

I'd just like to comment on a detail of memory mapping:

On Wed, Jan 31, 2018 at 10:54 PM, Ken Russell <kbr@google.com> wrote:
>
> the same mapped memory given back by the GPU. Instead
>

It's actually impossible to do this on any platform unless Kernel/Driver
vendors patch their software. On all platforms the mechanism used to
establish the gpu/cpu memory map uses low-level machine interfaces to
accomplish this goal, bypassing structured memory mapping facilities
provided by the host operating system. Conversely, the permissions on
user-land (as opposed to kernel-land) processes does not allow them to
interface with the MM directly, and so they have to go trough the host
operating system interfaces to establish memory maps. These two methods of
establishing maps cannot interoperate (sadly).

Attempts at doing it by using clever workarounds usually end up with
segfaults (at best) or machine crashes.