Re: [RFC PATCH 0/3] Memory Controller eBPF support

[hui . zhu]

2025年11月25日 20:55, "Michal Hocko" <mhocko@xxxxxxxx mailto:mhocko@xxxxxxxx?to=%22Michal%20Hocko%22%20%3Cmhocko%40suse.com%3E > 写到:


> 
> On Tue 25-11-25 12:39:11, hui.zhu@xxxxxxxxx wrote:
> 
> > 
> > My goal is implement dynamic memory reclamation for memcgs without limits,
> >  triggered by specific conditions.
> >  
> >  For instance, with memcg A and memcg B both unlimited, when memcg A faces
> >  high PSI pressure, ebpf control memcg B do some memory reclaim work when
> >  it try charge.
> > 
> Understood. Please also think whether this is already possible with
> existing interfaces and if not what are roadblocks in that direction.

I think it's possible to implement a userspace program using the existing
PSI userspace interfaces and the control interfaces provided by memcg to
accomplish this task.
However, this approach has several limitations:
the entire process depends on the continuous execution of the userspace
program, response latency is higher, and we cannot perform fine-grained
operations on target memcg.

Now that Roman has provided PSI eBPF functionality at
https://lore.kernel.org/lkml/20251027231727.472628-1-roman.gushchin@xxxxxxxxx/
Maybe we could add eBPF support to memcg as well, allowing us to implement
the entire functionality directly in the kernel through eBPF.

Best,
Hui

> 
> Thanks!
> -- 
> Michal Hocko
> SUSE Labs
>