>> If so, could you share little more insight on how that time measure >> outside of the cpu's cgroup cycles? Just so that its helpful to wider >> audience. > > Well, there are a number of things that I can think of that the kernel does > on behalf of processes that can consume processor time that isn't trivial to > account: > * Updating timers on behalf of userspace processes (itimers or similar). > * Sending certain kernel generated signals to processes (that is, stuff > generated by the kernel like SIGFPE, SIGSEGV, and so forth). > * Queuing events from dnotify/inotify/fanotify. > * TLB misses, page faults, and swapping. > * Setting up new processes prior to them actually running. > * Scheduling. > All of these are things that fork-bombs can and (other than TLB misses) do > exploit to bring a system down, and the cpu cgroup is by no means a magic > bullet to handle this. I feel like these are backed by different resources, and we should work on limiting those *at the source* in the context of a controller rather than just patching up the symptoms (too many forks causing issues), because these are symptoms of a larger issue IMO. -- Aleksa Sarai (cyphar) www.cyphar.com -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
