Messages in this thread | | | Date | Fri, 4 Apr 2008 09:11:06 -0500 | From | "Serge E. Hallyn" <> | Subject | Re: [Devel] [RFC PATCH 0/4] Container Freezer: Reuse Suspend Freezer |
| |
Quoting Paul Menage (menage@google.com): > On Thu, Apr 3, 2008 at 2:03 PM, <matthltc@us.ibm.com> wrote: > > > > * "freezer.kill" > > > > writing <n> will send signal number <n> to all tasks > > > > My first thought (not having looked at the code yet) is that sending a > signal doesn't really have anything to do with freezing, so it > shouldn't be in the same subsystem. Maybe a separate subsystem called > "signal"? > > And more than that, it's not something that requires any particular > per-process state, so there's no reason that the subsystem that > provides the "kill" functionality shouldn't be able to be mounted in > multiple hierarchies. > > How about if I added support for stateless subsystems, that could > potentially be mounted in multiple hierarchies at once? They wouldn't > need an entry in the css set, since they have no state. > > > * Usage : > > > > # mkdir /containers/freezer > > # mount -t container -ofreezer freezer /containers/freezer > > # mkdir /containers/freezer/0 > > # echo $some_pid > /containers/freezer/0/tasks > > > > to get status of the freezer subsystem : > > > > # cat /containers/freezer/0/freezer.freeze > > RUNNING > > > > to freeze all tasks in the container : > > > > # echo 1 > /containers/freezer/0/freezer.freeze > > # cat /containers/freezer/0/freezer.freeze > > FREEZING > > # cat /containers/freezer/0/freezer.freeze > > FROZEN > > Could we separate this out into two files? One called "freeze" that's > a 0/1 for whether we're intending to freeze the subsystem, and one > called "frozen" that indicates whether it is frozen? And maybe a > "state" file to report the RUNNING/FREEZING/FROZEN distinction in a > human-readable way?
One thing Oren had mentioned for checkpoint/restart was having more states - i.e. restoring, checkpointing... So then (assuming we used this subsys for that) we'd have more than the two files. Which is probably fine, just wanted to point that out.
-serge
| |