Messages in this thread | | | Subject | Re: system gets stuck in a lock during boot | From | Peter Zijlstra <> | Date | Mon, 24 Aug 2009 08:55:25 +0200 |
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On Mon, 2009-08-24 at 14:13 +0800, Li Zefan wrote: > Peter Zijlstra wrote: > > On Mon, 2009-08-24 at 10:41 +0800, Li Zefan wrote: > > > >>> @@ -940,7 +940,7 @@ event_create_dir(struct ftrace_event_call *call, struct dentr > >>> entry = trace_create_file("enable", 0644, call->dir, call, > >>> enable); > >>> > >>> - if (call->id) > >>> + if (call->id && call->profile_enable) > >> We do an extra check on ->profile_enable, shouldn't cause bug.. > >> > >>> entry = trace_create_file("id", 0444, call->dir, call, > >>> id); > >> Any way, I don't think this commit does the right thing: > >> > >> - If CONFIG_EVENT_PROFILE=y, we'll create events/<dir>/<event>/id, > >> except events/ftrace/<event>/id. > >> > >> - if CONFIG_EVENT_PROFILE=n, there's no 'id' file at all! > >> > >> I think it's better to skip ftrace/ dir in perf tool code, instead of > >> skipping creating id files in ftrace code. > > > > No, it does do the right thing. Your patch breaks things because not all > > tracepoints are created through TRACE_EVENT() and will thus not have > > their profile_enable/disable hooks set. > > > > By giving them an ID file, there is no way to distinguish good from bad > > tracepoints. > > > > But removing the id file from events/ftrace/ might break some ftrace > binary parsers? > > And this commit makes 'id' file disapeared with CONFIG_EVENT_PROFILE=n.
I introduced the id file for EVENT_PROFILE, tough luck if someone else relies on it.
> > Expempting ftrace is no solid solution, suppose someone else does a > > TRACE_EVENT_FORMAT() tracepoint, how would you know you could use it as > > a profile event source? > > > > Agree. > > > The id files really must stay conditional. > > > > I don't think it's a good idea to connect it with perfcounter > this way. Wouldn't adding a 'profilable' file more intuitive?
its called: id ;-)
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