Messages in this thread | | | Date | Tue, 14 Jul 2015 17:31:48 -0400 | From | Tejun Heo <> | Subject | Re: [PATCH v14 4/4] cgroup: implement the PIDs subsystem |
| |
On Wed, Jun 10, 2015 at 01:53:04PM +0900, Tejun Heo wrote: > On Tue, Jun 09, 2015 at 09:32:10PM +1000, Aleksa Sarai wrote: > > Adds a new single-purpose PIDs subsystem to limit the number of > > tasks that can be forked inside a cgroup. Essentially this is an > > implementation of RLIMIT_NPROC that applies to a cgroup rather than a > > process tree. > > > > However, it should be noted that organisational operations (adding and > > removing tasks from a PIDs hierarchy) will *not* be prevented. Rather, > > the number of tasks in the hierarchy cannot exceed the limit through > > forking. This is due to the fact that, in the unified hierarchy, attach > > cannot fail (and it is not possible for a task to overcome its PIDs > > cgroup policy limit by attaching to a child cgroup -- even if migrating > > mid-fork it must be able to fork in the parent first). > > > > PIDs are fundamentally a global resource, and it is possible to reach > > PID exhaustion inside a cgroup without hitting any reasonable kmemcg > > policy. Once you've hit PID exhaustion, you're only in a marginally > > better state than OOM. This subsystem allows PID exhaustion inside a > > cgroup to be prevented. > > Patches 3-4 look good to me. Will apply once v4.3 dev window opens.
Applied 3-4 to cgroup/for-4.3.
Thanks.
-- tejun
| |