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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: Djalal Harouni <tixxdz@gmail.com>,
	Zefan Li <lizefan.x@bytedance.com>,
	 Johannes Weiner <hannes@cmpxchg.org>,
	Alexei Starovoitov <ast@kernel.org>,
	 Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	 Martin KaFai Lau <martin.lau@linux.dev>,
	Eduard Zingerman <eddyz87@gmail.com>, Song Liu <song@kernel.org>,
	 Yonghong Song <yonghong.song@linux.dev>,
	John Fastabend <john.fastabend@gmail.com>,
	 KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	 Jiri Olsa <jolsa@kernel.org>, Mykola Lysenko <mykolal@fb.com>,
	Shuah Khan <shuah@kernel.org>,
	 LKML <linux-kernel@vger.kernel.org>,
	 "open list:CONTROL GROUP (CGROUP)" <cgroups@vger.kernel.org>,
	bpf <bpf@vger.kernel.org>,
	 "open list:KERNEL SELFTEST FRAMEWORK"
	<linux-kselftest@vger.kernel.org>
Subject: Re: [RFC PATCH bpf-next 0/3] bpf: freeze a task cgroup from bpf
Date: Thu, 28 Mar 2024 10:32:24 -0700	[thread overview]
Message-ID: <CAADnVQK6BUGZFCATD8Ejcfob5sKK-b8HUD_4o8Q6s9FM72L4iQ@mail.gmail.com> (raw)
In-Reply-To: <ZgWnPZtwBYfHEFzf@slm.duckdns.org>

On Thu, Mar 28, 2024 at 10:22 AM Tejun Heo <tj@kernel.org> wrote:
>
> Hello, Djalal.
>
> On Wed, Mar 27, 2024 at 11:53:22PM +0100, Djalal Harouni wrote:
> > This patch series adds support to freeze the task cgroup hierarchy
> > that is on a default cgroup v2 without going through kernfs interface.
> >
> > For some cases we want to freeze the cgroup of a task based on some
> > signals, doing so from bpf is better than user space which could be
> > too late.
> >
> > Planned users of this feature are: tetragon and systemd when freezing
> > a cgroup hierarchy that could be a K8s pod, container, system service
> > or a user session.
> >
> > Patch 1: cgroup: add cgroup_freeze_no_kn() to freeze a cgroup from bpf
> > Patch 2: bpf: add bpf_task_freeze_cgroup() to freeze the cgroup of a task
> > Patch 3: selftests/bpf: add selftest for bpf_task_freeze_cgroup
>
> It bothers me a bit that it's adding a dedicated interface for something
> which already has a defined userspace interface. Would it be better to have
> kfunc wrappers for kernel_read() and kernel_write()?

How would that look ?
prog cannot and shouldn't open a file.
The seq_file would be passed/pinned by user space?

  reply	other threads:[~2024-03-28 17:32 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20240327-ccb56fc7a6e80136db80876c@djalal>
2024-03-27 22:53 ` [RFC PATCH bpf-next 0/3] bpf: freeze a task cgroup from bpf Djalal Harouni
2024-03-27 22:53   ` [RFC PATCH bpf-next 1/3] cgroup: add cgroup_freeze_no_kn() to freeze a " Djalal Harouni
2024-03-27 22:53   ` [RFC PATCH bpf-next 2/3] bpf: add bpf_task_freeze_cgroup() to freeze the cgroup of a task Djalal Harouni
2024-03-27 22:53   ` [RFC PATCH bpf-next 3/3] selftests/bpf: add selftest for bpf_task_freeze_cgroup Djalal Harouni
2024-03-28 17:22   ` [RFC PATCH bpf-next 0/3] bpf: freeze a task cgroup from bpf Tejun Heo
2024-03-28 17:32     ` Alexei Starovoitov [this message]
2024-03-28 17:58       ` Tejun Heo
2024-03-28 19:46         ` Alexei Starovoitov
2024-03-28 20:02           ` Tejun Heo
2024-03-28 20:45             ` Alexei Starovoitov
2024-03-28 21:01               ` Tejun Heo
2024-03-28 21:28                 ` Alexei Starovoitov
2024-03-28 23:23                   ` Tejun Heo
2024-03-29 13:22                 ` Djalal Harouni
2024-03-29 21:39                   ` Tejun Heo
2024-03-29 23:04                     ` Alexei Starovoitov
2024-04-02 17:40                       ` Djalal Harouni
2024-04-02 17:16   ` Michal Koutný
2024-04-02 18:20     ` Djalal Harouni
2024-04-09 15:32       ` Michal Koutný
2024-04-11  0:26         ` Yonghong Song
2024-04-11  8:25           ` Michal Koutný
2024-04-11  8:36         ` Djalal Harouni

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