Re: [PATCH] cgroup/dmem: accept only one region per limit write

[Tejun Heo <tj@kernel.org>]

On Sat, Jun 06, 2026 at 11:44:10PM +0200, Maarten Lankhorst wrote:
> > As I see it, we could go down one of two paths:
> > 1. We go ahead with the patch as proposed, and I make sure that the users I know of adapt. Could be a bit icky wrt. "do not break userspace" rules, but since the already use non-merged UAPIs in one place, you can argue that these users kind of have to expect breakage.
> > 2. We use the old handling allowing multiple lines for dmem.min and dmem.low only. This preserves compatibility but uglifies the code by quite a bit.
> > 
> > All things considered, I think I personally would prefer going with 1. and taking the patch as proposed and just having one codepath handling every limit file. Just highlighting this so we don't do it on accident.
> > 
> > [1] https://patchwork.freedesktop.org/series/163183/
> > 
> 
> I prefer option 1 as well, but would like an ack from one of the core cgroup maintainers too,
> and what Maxime's opinion on this as well.

Yeah, if at all possible, please drop the multi region write support if at
all possible. This shouldn't have gotten in and yeah it's on the boundary
but the fact that users need external patches works in our favor - both
qualitatively and quantatively (the usage is likely tiny).

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun