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From: Jonathan Corbet <corbet@lwn.net>
To: Christian Brauner <brauner@kernel.org>, Tejun Heo <tj@kernel.org>, Roman
 Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>, Zefan Li <lizefan.x@bytedance.com>,
 Johannes Weiner <hannes@cmpxchg.org>, cgroups@vger.kernel.org,
 containers@lists.linux.dev, Christian Brauner
 <christian.brauner@ubuntu.com>, Serge Hallyn <serge@hallyn.com>
Subject: Re: [PATCH v3 1/5] cgroup: introduce cgroup.kill
In-Reply-To: <20210508121542.1269256-1-brauner@kernel.org>
References: <20210508121542.1269256-1-brauner@kernel.org>
Date: Mon, 10 May 2021 09:39:02 -0600
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Christian Brauner <brauner@kernel.org> writes:

> Introduce the cgroup.kill file. It does what it says on the tin and
> allows a caller to kill a cgroup by writing "1" into cgroup.kill.
> The file is available in non-root cgroups.

So I feel like I'm missing something fundamental here...perhaps somebody
can supply a suitable cluebat.  It seems inevitable to me that, sooner
or later, somebody will surely wish that this mechanism could send a
signal other than SIGKILL, but this interface won't allow that.  Even if
you won't want to implement an arbitrary signal now, it seems like
defining the interface to require writing "9" rather than "1" would
avoid closing that option off in the future.

I assume there's some reason why you don't want to do that, but I'm to
slow to figure out what it is...?

Thanks,

jon