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

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Message-ID: <87af0c7a8fc35cd96519a4e3f09d39918bdb7370@linux.dev>
Date: Wed, 26 Nov 2025 03:05:32 +0000
From: hui.zhu@...ux.dev
To: "Michal Hocko" <mhocko@...e.com>
Cc: "Roman Gushchin" <roman.gushchin@...ux.dev>, "Andrew Morton"
 <akpm@...ux-foundation.org>, "Johannes Weiner" <hannes@...xchg.org>,
 "Shakeel Butt" <shakeel.butt@...ux.dev>, "Muchun Song"
 <muchun.song@...ux.dev>, "Alexei Starovoitov" <ast@...nel.org>, "Daniel
 Borkmann" <daniel@...earbox.net>, "Andrii Nakryiko" <andrii@...nel.org>,
 "Martin KaFai Lau" <martin.lau@...ux.dev>, "Eduard Zingerman"
 <eddyz87@...il.com>, "Song Liu" <song@...nel.org>, "Yonghong Song"
 <yonghong.song@...ux.dev>, "John Fastabend" <john.fastabend@...il.com>,
 "KP Singh" <kpsingh@...nel.org>, "Stanislav Fomichev" <sdf@...ichev.me>,
 "Hao Luo" <haoluo@...gle.com>, "Jiri Olsa" <jolsa@...nel.org>, "Shuah
 Khan" <shuah@...nel.org>, "Peter Zijlstra" <peterz@...radead.org>,
 "Miguel Ojeda" <ojeda@...nel.org>, "Nathan Chancellor"
 <nathan@...nel.org>, "Kees Cook" <kees@...nel.org>, "Tejun Heo"
 <tj@...nel.org>, "Jeff Xu" <jeffxu@...omium.org>, mkoutny@...e.com, "Jan
 Hendrik Farr" <kernel@...rr.cc>, "Christian Brauner"
 <brauner@...nel.org>, "Randy Dunlap" <rdunlap@...radead.org>, "Brian
 Gerst" <brgerst@...il.com>, "Masahiro Yamada" <masahiroy@...nel.org>,
 linux-kernel@...r.kernel.org, linux-mm@...ck.org,
 cgroups@...r.kernel.org, bpf@...r.kernel.org,
 linux-kselftest@...r.kernel.org, "Hui Zhu" <zhuhui@...inos.cn>
Subject: Re: [RFC PATCH 0/3] Memory Controller eBPF support

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


> 
> On Tue 25-11-25 12:39:11, hui.zhu@...ux.dev 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@linux.dev/
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
>