Hello, Michal. On Thu, Jan 24, 2019 at 09:22:52AM +0100, Michal Hocko wrote: > I do not think we can do that for two reasons. It breaks the existing > semantic userspace might depend on and more importantly this is not a > correct behavior IMO. This is a valid concern but I'll come back to this later. > You have to realize that stats are hierarchical because that is how we > account. Events represent a way to inform that something has happened at > the specific level of the tree though. If you do not setup low/high/max This isn't true. e.g. cgroup.events's populated event is hierarchical. Everything in cgroup should be hierarchical by default. > limit then you simply cannot expect to be informed those get hit because > they cannot by definition. Or put it other way, if you are waiting for > those events you really want to know the (sub)tree they happened and if > you propagate the event up the hierarchy you have hard time to tell that > (you would basically have to exclude all but the lowest one and that is > an awkward semantic at best. I don't think it's a good idea to argue this for each piece of information. Again, everything should be hierarchical unless there are clear and strong reasons against; otherwise, we end up with random mix of hierarchical and flat behaviors, something that we want to avoid the most - remember .use_hierarchy?. > Maybe we want to document this better but I do not see we are going to > change the behavior. I beg you to reconsider. This was a clear oversight and the cgroup2 usage is still relatively limited. We sure can add local-specific counters if needed but must not mix local and hierarchical counters without a clear way to tell what's what. Thanks. -- tejun
