Messages in this thread | | | Subject | Re: [RFC simple allocator v1 0/2] Simple allocator | From | Laura Abbott <> | Date | Wed, 25 Jan 2017 10:13:05 +0100 |
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On 01/23/2017 09:35 AM, Daniel Vetter wrote: > On Fri, Jan 20, 2017 at 04:32:29PM +0100, Benjamin Gaignard wrote: >> The goal of this RFC is to understand if a common ioctl for specific memory >> regions allocations is needed/welcome. >> >> Obviously it will not replace allocation done in linux kernel frameworks like >> v4l2, drm/kms or others, but offer an alternative when you don't want/need to >> use them for buffer allocation. >> To keep a compatibility with what already exist allocated buffers are exported >> in userland as dmabuf file descriptor (like ION is doing). >> >> "Unix Device Memory Allocator" project [1] wants to create a userland library >> which may allow to select, depending of the devices constraint, the best >> back-end for allocation. With this RFC I would to propose to have common ioctl >> for a maximum of allocators to avoid to duplicated back-ends for this library. >> >> One of the issues that lead me to propose this RFC it is that since the beginning >> it is a problem to allocate contiguous memory (CMA) without using v4l2 or >> drm/kms so the first allocator available in this RFC use CMA memory. >> >> An other question is: do we have others memory regions that could be interested >> by this new framework ? I have in mind that some title memory regions could use >> it or replace ION heaps (system, carveout, etc...). >> Maybe it only solve CMA allocation issue, in this case there is no need to create >> a new framework but only a dedicated ioctl. >> >> Maybe the first thing to do is to change the name and the location of this >> module, suggestions are welcome. >> >> I have testing this code with the following program: > > I'm still maintaining that we should just destage ION (with the todo items > fixed), since that is already an uabi to do this (afaiui at least), and > it's used on a few devices ... Please chat with Laura Abott. > -Daniel >
(I thought I sent this before but apparently it didn't go through. Apologies if this ends up as a repeat for anyone)
I've been reviewing this as well. Even if Ion is used on a number of devices, the model is still a bit clunky. I was hoping to see if it could be re-written from scratch in a framework like this and then either add a shim layer or just coax all devices out there to actually convert to the new framework.
I supposed another option is to destage as you suggested and work on an improved version in parallel.
Thanks, Laura
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