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From: Tejun Heo <tj@kernel.org>
To: Djalal Harouni <tixxdz@gmail.com>
Cc: 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>,
	linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
	bpf@vger.kernel.org, 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 07:22:05 -1000	[thread overview]
Message-ID: <ZgWnPZtwBYfHEFzf@slm.duckdns.org> (raw)
In-Reply-To: <20240327225334.58474-1-tixxdz@gmail.com>

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()?

Thanks.

-- 
tejun

  parent reply	other threads:[~2024-03-28 17:22 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   ` Tejun Heo [this message]
2024-03-28 17:32     ` [RFC PATCH bpf-next 0/3] bpf: freeze a task cgroup from bpf Alexei Starovoitov
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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