Re: [PATCH v7 3/6] cgroup/dmem: Add reclaim callback for lowering max below current usage

[Thomas Hellström]

Hi,

On Mon, 2026-07-06 at 09:25 -1000, Tejun Heo wrote:
> Hello,
> 
> On Fri, Jul 03, 2026 at 03:05:38PM +0200, Thomas Hellström wrote:
> > Also honor O_NONBLOCK so that if that flag is set during the
> > max value write, no reclaim is initiated. The idea is to avoid
> > charging the reclaim cost to the writer of the max value.
> 
> Is this really necessary? I'm not necessarily against it but this is
> trivial
> to work around from userspace and feels like a gratuitous addition.
> What's
> the use case?

This was something that was added at the request of Maarten. The idea
is to mimic the memcg behaviour. For memcg, the use-case was to avoid
having the reclaim cost (I assume in terms of cpu time) land on the
next allocator instead of the process writing the new max value.

I think there are more details in the memcg commit history, but the
presence here is solely to mimic memcg WRT this.

Thanks,
Thomas 

> 
> Thanks.