----- Original Message ----- > From: "Mathieu Desnoyers" <[email protected]> > To: "Steven Rostedt" <[email protected]> > Cc: "Frank Ch. Eigler" <[email protected]>, [email protected], "Ingo > Molnar" <[email protected]>, "Frederic > Weisbecker" <[email protected]>, "Andrew Morton" > <[email protected]>, "Johannes Berg" > <[email protected]>, "Linus Torvalds" <[email protected]>, > "Peter Zijlstra" > <[email protected]>, "Thomas Gleixner" <[email protected]>, "Greg > Kroah-Hartman" <[email protected]>, > "lttng-dev" <[email protected]>, "Rusty Russell" > <[email protected]>, "Andi Kleen" <[email protected]> > Sent: Wednesday, March 12, 2014 11:10:53 PM > Subject: Re: [for-next][PATCH 08/20] tracing: Warn if a tracepoint is not set > via debugfs > > ----- Original Message ----- > > From: "Steven Rostedt" <[email protected]> > > To: "Mathieu Desnoyers" <[email protected]> > > Cc: "Frank Ch. Eigler" <[email protected]>, [email protected], > > "Ingo Molnar" <[email protected]>, "Frederic > > Weisbecker" <[email protected]>, "Andrew Morton" > > <[email protected]>, "Johannes Berg" > > <[email protected]>, "Linus Torvalds" > > <[email protected]>, "Peter Zijlstra" > > <[email protected]>, "Thomas Gleixner" <[email protected]>, "Greg > > Kroah-Hartman" <[email protected]>, > > "lttng-dev" <[email protected]>, "Rusty Russell" > > <[email protected]>, "Andi Kleen" <[email protected]> > > Sent: Wednesday, March 12, 2014 8:49:07 PM > > Subject: Re: [for-next][PATCH 08/20] tracing: Warn if a tracepoint is not > > set via debugfs > > > > On Wed, 12 Mar 2014 19:51:01 +0000 (UTC) > > Mathieu Desnoyers <[email protected]> wrote: > > > > > This only leaves tracepoints in header files and the impact of LTO as > > > requirements for having tracepoint callsites with the same name across > > > modules. > > > > The only thing that needs to be unique is the struct tracepoint > > __tracepoint_##name. There should not be any duplicates of those. I > > can't see how the LTO would duplicate a data structure without screwing > > everything (not just tracepoints) up. > > > > We can still have more than one trace_##name() called, as that is > > handled by the static key. > > Hrm, I seem to have mixed up the concerns regarding compiler > optimisations between the static keys with those related to tracepoints > (including that their predecessors "kernel markers" worked more like > static keys than tracepoint). I did work in both area pretty much at the > same time back in 2007-2008. > > Having gotten my head back up straight, I now see the point in your > proposal. Thanks for bearing with me. > > Even if we ever want to have tracepoints within header files, as long > as we have the DECLARE_TRACE() within the header, and a DEFINE_TRACE() > in one location in the loaded kernel image (or a loaded module we depend > on), it should be possible too. All tracepoint.c cares about is the site > defined by DEFINE_TRACE().
I just prepared a patch implementing your idea. I will post it as RFC very soon. The callers will still need to be adapted, so this is just to show the tracepoint.c/h modifications. Thanks! Mathieu > > > > > Note, I'm scrambling to get ready for my trip tomorrow. Thus, I'm not > > as much at the computer. I may work on some patches in my 6 hour > > layover though. > > Allright. Have a good trip! > > Thanks, > > Mathieu > > > > > -- Steve > > > > -- > Mathieu Desnoyers > EfficiOS Inc. > http://www.efficios.com > -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
