* Peter Zijlstra <pet...@infradead.org> wrote:
> On Fri, Jul 11, 2014 at 01:56:19PM +0200, Jiri Olsa wrote:
> > From: Jiri Olsa <jo...@redhat.com>
> >
> > When task exits we close:
> > 1) all events that are installed in task
> > 2) all events owned by task (via file descriptor)
> >
> > But we don't close children events of 2) events. Those children
> > events stay until the child task exits and are useless with the
> > parent being gone, because we have no way to get to values any
> > more.
> >
> > Plus if the event stays installed in task even with the owner task
> > gone, it runs the perf callback any time the task forks, for no
> > real reason.
> >
> > Closing all children events events when the owner task of the
> > parent event is closed.
>
> So I _think_ the reason we didn't do this is because this is potentially
> very expensive and keeping them around isn't too much bother, they'll
> die eventually.
>
> But I can't really remember. Ingo any recollections / opinions?
As far as I can remember it's just a historic path dependent
implementation detail, not really a conscious choice: initially we
didn't remove events (because we couldn't), and then it remained so
because it broke nothing.
Thanks,
Ingo
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