Re: [RFC]: m2m dec reports the graphics memory requirement

[Sergey Senozhatsky <senozhatsky@chromium.org>]

On (23/07/27 17:17), Tomasz Figa wrote:
> On Fri, Jun 30, 2023 at 7:47 PM Hsia-Jun Li <Randy.Li@synaptics.com> wrote:
> >
> > Hello All
> >
> > This RFC tries to address the following problems:
> >
> > 1. Application may request too many buffers, increasing pressure to
> > system's memory allocator(Thinking about running Android with 8K UHD
> > playback in a system with only 2 GiB memory available);
> >
> 
> Yeah, I think that's something that has to be addressed. It was also
> mentioned recently in the review of the DELETE_BUF series. I think we
> need some kind of accounting of the allocations to the processes, so
> that the per-process limits of memory usage could apply. Let me add
> +Sergey Senozhatsky who often crosses his path with kernel memory
> management.

That's an interesting topic. The usual approach would be memcg: we
create a memory controller, set memory usage limit, then move tasks
under that controller. The last part is problematic, as it implies
a well-behaving user-space. I'm not aware of a simple way (or any
way for that matter) to "automatically enforce" memcg on a process
group.

From what I can tell networking code attempts to "enforce" memcg on its
allocations, and hence has to manually charge memcg. For instance, take
a look at sock_reserve_memory() and corresponding mem_cgroup_charge_skmem()
call.

So I wonder if we can take a closer look at what networking does and
do something similar in vb2.