Re: [RFC] [PATCH 2/2] cgroups: make procs file writable

[Paul Menage]

On Wed, Jun 2, 2010 at 1:20 PM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
>
> Yes sure. The main thread can exit via sys_exit(), this doesn't affect
> the thread group. Of course, I am not saying this is common practice,
> perhaps no "important" app does this.

This check has been in cgroups for quite a while and no-one's
complained so far...

> But I still can't understand why we can't just remove it. Both
> cgroup_attach_task() and cgroup_attach_proc() should handle the
> possible races correctly anyway.

The "it" that you're proposing to remove is in fact the code that
handles those races.

Anyway, I think this issue is orthogonal to the movability of entire
processes - with Ben's patch, an exited-but-not-reaped group leader is
immovable either via "tasks" or "cgroup.procs". Changing the race
condition handling to allow such movement would be a separate issue.

Paul

Paul
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