Re: [PATCH v2 2/2] cgroup/dmem: add dmem.memcg control file for double-charging to memcg

[Tejun Heo]

Hello,

On Fri, May 22, 2026 at 05:26:16PM +0200, Michal Koutný wrote:
> Hello Eric.
> 
> On Tue, May 19, 2026 at 11:59:02AM -0400, Eric Chanudet <echanude@xxxxxxxxxx> wrote:
> > Add a root-only cgroupfs file "dmem.memcg" that lets an administrator
> > configure whether allocations in a dmem region should also be charged to
> > the memory controller.
> 
> This kinda makes sense as it is not unlike io.cost.* device
> configurators.
> 
> Just for my better understanding -- will there be a space for userspace
> to switch this? (No charged dmem allocations happen before responsible
> userspace runs, so that the attribute remains unlocked.)
> 
> (I'm rather indifferent about the actual double charging/non-charging
> matter.)

I wonder whether this would make more sense as a mount flag? What's the use
case for e.g. having different config for different devices? Wouldn't that
be really confusing?

Thanks.

-- 
tejun