Messages in this thread | | | Date | Fri, 09 Jan 2009 14:14:55 +0800 | From | Li Zefan <> | Subject | Re: [RFC][PATCH] NOOP cgroup subsystem |
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KAMEZAWA Hiroyuki wrote: > How about this idea ? Any comments are welcome. > > -Kame > > == > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > > Add an NO OPERATION cgroup subsystem. > > Cgroup itself is providing a feature to attach a task(PID) to some class. > This feature itself is very useful but "no operation" cgroup is not supported > now other than debug cgroup. (But debug cgroup should be for DEBUG. distro > may not configure it.) >
Then how can we make sure distro will configure this noop subsys. :)
Or we can make the debug subsys always configured if CONFIG_CGROUP=y ? The debug system adds no runtime overhead, and it's about 100 lines of code only.
> Motivation: Simply classify Applications by cgroup > When using cgroup for classifying applications, some kind of "control" or > "account" subsys must be used. For flexible use of cgroup's nature of > classifying applications, NOOP is useful. It can be used regardless of > resource accounting unit or name spaces or some controls. > IOW, NOOP cgroup allows users to tie PIDs with some nickname. > > After this, application can be checked whether it's still alive or not by > > mount -t cgroup none /var/apps noop > mkdir /var/apps/mydaemon > echo 0 > /var/apps/mydaemon > /etc/init.d/mydaemon start > exit > > This can be used as the same technique of "recording pid into /var/run/xxx.pid" > and not necessary to remove stale files. If mydaemon dies, tasks file will > be empty and notify_on_release handler can be used. > > I myself want to use this for replacement of "ps -elf | grep" if libcgroup supports > ps under cgroup. > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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