Re: [PATCH 0/7] kernel/cgroups: Add "dev" memory accounting cgroup.

[Tejun Heo <tj@kernel.org>]

Hello,

On Wed, Oct 23, 2024 at 09:52:53AM +0200, Maarten Lankhorst wrote:
> New submission!
> I've added documentation for each call, and integrated the renaming from
> drm cgroup to dev cgroup, based on maxime ripard's work.
> 
> Maxime has been testing this with dma-buf heaps and v4l2 too, and it seems to work.
> In the initial submission, I've decided to only add the smallest enablement possible,
> to have less chance of breaking things.
> 
> The API has been changed slightly, from "$name region.$regionname=$limit" in a file called
> dev.min/low/max to "$subsystem/$name $regionname=$limit" in a file called dev.region.min/low/max.
> 
> This hopefully allows us to perhaps extend the API later on with the possibility to
> set scheduler weights on the device, like in
> 
> https://blogs.igalia.com/tursulin/drm-scheduling-cgroup-controller/
> 
> Maarten Lankhorst (5):
>   kernel/cgroup: Add "dev" memory accounting cgroup

Yeah, let's not use "dev" name for this. As Waiman pointed out, it conflicts
with the devices controller from cgroup1. While cgroup1 is mostly
deprecated, the same features are provided through BPF in systemd using the
same terminologies, so this is going to be really confusing.

What happened with Tvrtko's weighted implementation? I've seen many proposed
patchsets in this area but as far as I could see none could establish
consensus among GPU crowd and that's one of the reasons why nothing ever
landed. Is the aim of this patchset establishing such consensus?

If reaching consensus doesn't seem feasible in a predictable timeframe, my
suggesstion is just extending the misc controller. If the only way forward
here is fragmented vendor(s)-specific implementations, let's throw them into
the misc controller.

Thanks.

-- 
tejun