Re: [PATCH] cgroup: add tracepoints to track cgroup events

[Andrea Righi <andrea@betterlinux.com>]

On Thu, Aug 21, 2014 at 07:45:14PM -0400, Steven Rostedt wrote:
> On Thu, 21 Aug 2014 12:07:01 -0500
> Tejun Heo <tj@kernel.org> wrote:
> 
> > Hello, Anrea.
> > 
> > On Thu, Aug 21, 2014 at 11:00:02AM -0600, Andrea Righi wrote:
> > > hmm... am I missing something or we already support directory events?
> > 
> > Ah, right, those mkdir/rmdir and writes automatically generate those
> > events.
> > 
> > > root@Dell:~# grep cgroups /proc/mounts
> > > none /cgroups cgroup rw,relatime,cpuset,cpu,cpuacct,memory,devices,freezer,perf_event,hugetlb 0 0
> > > root@Dell:~# inotifywait -m -r -e modify -e move -e create -e delete /cgroups
> > > Setting up watches.  Beware: since -r was given, this may take a while!
> > > Watches established.
> > > /cgroups/ CREATE,ISDIR test
> > > /cgroups/test/ MODIFY cgroup.procs
> > > /cgroups/test/ MODIFY cgroup.procs
> > > /cgroups/test/ MODIFY cgroup.populated
> > > /cgroups/ MODIFY cgroup.procs
> > > /cgroups/ MODIFY cgroup.procs
> > > /cgroups/test/ MODIFY cgroup.populated
> > > /cgroups/ DELETE,ISDIR test
> > > 
> > > I still need to figure out a smart way to track which PIDs are
> > > added/removed to/from cgroup.procs from userland (inotifywait + git? :)),
> > > but all the other informations provided by my tracepoint patch seem to
> > > be already available via [di]notify.
> > 
> > Hmmm... yeah, determining exactly which pids got added / removed can
> > be cumbersome from just MODIFY events.  That said, what are you trying
> > to do with such information?
> > 
> 
> OK, is this patch not being pushed then? I have a lot of comments to
> make about it, but if this patch is being dropped for another way of
> doing things I wont waste my time on it.
> 
> Thanks,
> 
> -- Steve

Comments are always welcome, but at this point I'd say we can drop this
patch, so don't waste your time on it. I can find an alternative way to
get the same informations from user-space.

Thanks,
-Andrea