Messages in this thread | | | Date | Sat, 22 Oct 2011 17:28:41 +0200 | From | Lennart Poettering <> | Subject | Re: A Plumber’ s Wish List for Linux |
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On Sat, 22.10.11 12:21, Frederic Weisbecker (fweisbec@gmail.com) wrote:
> If you really need to stop any forks in a cgroup, then a cgroup core feature > handling that very single purpose would be better and more efficient.
We'd be happy with that and this is what we originally suggested actually.
> That said I'm not really sure why you're using cgroups in Systemd.
We want to reliably label processes in a hierarchial way, so that this is inherited by all child processes, cannot be overriden by unprivileged code (subject to some classic Unix access control handling) and get notifications when such a label stops referring to any process. We use that for sticking the service name on a process, so that all CGI processes of Apache are automatically assigned the same service as apache itself. And we want a notification when all of apache's processes die. And we also want to be able to kill Apache compeltely by killing all its processes.
cgroups provides us with all of that, though the last two items only in a suboptimal way: notification of cgroups running empty is ugly, since it is done by spawning a usermode helper (we'd prefer a netlink msg or so), and the process killing is a bit racy.
Lennart
-- Lennart Poettering - Red Hat, Inc.
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