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Date:   Wed, 29 Aug 2018 14:13:49 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Vince Weaver <vincent.weaver@maine.edu>
Cc:     linux-kernel@vger.kernel.org, Josh Poimboeuf <jpoimboe@redhat.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Stephane Eranian <eranian@google.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>
Subject: Re: [perf] perf_event.h ABI visibility question
Message-ID: <20180829121349.GT24124@hirez.programming.kicks-ass.net>
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On Tue, Aug 28, 2018 at 01:51:29PM -0400, Vince Weaver wrote:
> On Mon, 27 Aug 2018, Peter Zijlstra wrote:
> 
> > Something like so then?
> > 
> > diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
> > index eeb787b1c53c..f35eb72739c0 100644
> > --- a/include/uapi/linux/perf_event.h
> > +++ b/include/uapi/linux/perf_event.h
> > @@ -144,7 +144,7 @@ enum perf_event_sample_format {
> >  
> >  	PERF_SAMPLE_MAX = 1U << 20,		/* non-ABI */
> >  
> > -	__PERF_SAMPLE_CALLCHAIN_EARLY		= 1ULL << 63,
> > +	__PERF_SAMPLE_CALLCHAIN_EARLY		= 1ULL << 63, /* non-ABI; internal use */
> >  };
> 
> yes, something like that would be fine.
> 
> I am being difficult about this, but from experience when trying to keep 
> the manpage updated, what seems obvious now will not be so obvious 6 
> months from now and trying to dig through the git logs / mailing list 
> archives to verify the purpose of an addition can be a lot of work 
> sometimes.

Yeah, no worries. I appreciate you paying attention to these things.