Messages in this thread | | | Date | Wed, 12 Oct 2011 11:35:50 +0400 | From | Glauber Costa <> | Subject | Re: [PATCH 05/10] Make total_forks per-cgroup |
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On 10/12/2011 03:45 AM, Frederic Weisbecker wrote: > On Wed, Oct 05, 2011 at 04:12:00PM +0400, Glauber Costa wrote: >> On 10/05/2011 01:05 PM, Peter Zijlstra wrote: >>> On Sun, 2011-10-02 at 23:21 +0400, Glauber Costa wrote: >>>> This patch counts the total number of forks per-cgroup. >>>> The information is propagated to the parent, so the total >>>> number of forks in the system, is the parent cgroup's one. >>>> >>>> To achieve that, total_forks is made per-cpu. There is no >>>> particular reason to do that, but by doing this, we are >>>> able to bundle it inside the cpustat structure already >>>> present. >>> >>> I think fweisbec is also doing something with forks and cgroups. >> >> I am all ears... >> >> Frederic, does it conflict with what you're doing ? > > I don't know if that really conflicts but I'm working > on a cgroup subsystem that is able to control the number > of tasks running in a subsystem. > > It consists in two new files added: > > * tasks.usage > * tasks.limit > > The subsystem rejects any new fork or migration into the > cgroup when tasks.usage> tasks.limit > > So tasks.usage can inform you about the number of tasks > running into the cgroup. It's not strictly the number > of forks because it also counts the tasks that have been > attached to the cgroup. > > But something like a tasks.fork file could be implemented > in that subsystem as well. > > It depends on what you need.
So the specific piece I am working on, is to display /proc/stat information per-cgroup. One of the many fields it has, is total_forks. (it is actually just a small part of the series) So instead of tracking how many forks the system has in total, I'll track it per-cpucgroup.
So I don't think we conflict at all. At the very least, IIUC, you are planning to account and check *before* a fork happens, right? This particular stat is incremented after it already succeeded.
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