On Thu, Jul 11, 2013 at 12:59:32PM -0400, Steven Rostedt wrote: > On Thu, 2013-07-11 at 12:55 -0400, Steven Rostedt wrote: > > > > > > > Other than that, a function tracer environment that is safer to use might be > > > useful for other people as well. > > > > Not sure how to make the environment safe, as the main purpose of the > > function trace is to debug those hard to debug locations, like NMIs, > > RCU, dynamic ticks, etc. To ensure a "safe" environment, it would > > cripple the tracer. > > > > Hmm, what would you state as a safe environment? How can we detect if > > the environment is safe to trace or not? > > Maybe I misunderstood you. You mean to have this environment be > something for not just perf, and have the macro be: > > NONSAFE_TRACE(__local_bh_enable); > > ? > > Then, any ftrace user could set a flag in the registering of its ops to > 'safe_only_functions'. And it will ignore all of these locations. > There's really not many of them, so it may not be too hard to weed out. Yah, like that. But that doesn't invalidate your question as to what 'safe' would encompass. I think RCU/lockdep would be the big thing for perf, not sure it should be wider than that. -- To unsubscribe from this list: send the line "unsubscribe trinity" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
