linux-kernel - Re: [tip:perf/core] tracing: Add DEFINE_EVENT(), DEFINE_SINGLE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20091202162715.GB9710@Krystal>
Date:	Wed, 2 Dec 2009 11:27:15 -0500
From:	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Ingo Molnar <mingo@...e.hu>, mingo@...hat.com, hpa@...or.com,
	linux-kernel@...r.kernel.org, randy.dunlap@...cle.com,
	wcohen@...hat.com, fweisbec@...il.com, tglx@...utronix.de,
	jbaron@...hat.com, mhiramat@...hat.com,
	linux-tip-commits@...r.kernel.org, Christoph Hellwig <hch@....de>
Subject: Re: [tip:perf/core] tracing: Add DEFINE_EVENT(),
	DEFINE_SINGLE_EVENT() support to docbook

* Steven Rostedt (rostedt@...dmis.org) wrote:
> On Wed, 2009-12-02 at 15:43 +0100, Ingo Molnar wrote:
> > * Steven Rostedt <rostedt@...dmis.org> wrote:
> > 
> > > On Wed, 2009-12-02 at 15:01 +0100, Ingo Molnar wrote:
> > > 
> > > > >  DECLARE_CLASS_AND_DEFINE_EVENT()
> > > > 
> > > > Hm, that's a bit too long. How about 'DEFINE_CLASS_EVENT()' as a 
> > > > compromise? It's similarly short-ish to TRACE_EVENT(), and it also 
> > > > conveys the fact that we create both a class and an event there.
> > > > 
> > > > The full series would thus be:
> > > > 
> > > > 	DECLARE_EVENT_CLASS
> > > > 	DEFINE_EVENT
> > > > 	DEFINE_CLASS_EVENT
> > > > 
> > > > hm?
> > > 
> > > I thought about that too, but it actually makes it more confusing. 
> > > Because, looking at this with a fresh POV, I would think that after I 
> > > declare a class, I would use DEFINE_CLASS_EVENT with that class.
> > 
> > yeah. Hence was my second-best choice 'DEFINE_STANDALONE_EVENT' or 
> > 'DEFINE_SINGLE_EVENT' - to stress the special nature it, and to actually 
> > nudge people towards creating classes of events instead of doing 
> > separate, standalone points. (which are a waste in the majority of 
> > cases)
> 
> But the current TRACE_EVENT is still defining a class. Thus, you could
> create a TRACE_EVENT (or whatever it is called) and then create
> DEFINE_EVENTs based on the TRACE_EVENT.
> 
> That's why I want a name that describes this.
> 
> DEFINE_EVENT_CLASS?
> 
> Perhaps that's the best.
> 
> DECLARE_EVENT_CLASS - only creates a class
> DEFINE_EVENT - defines an event based off of a class
> DEFINE_EVENT_CLASS - creates a class and defines an event by the same name
> 
> Perhaps this is best in keeping with linux kernel naming conventions?

Hi Steve,

A few questions about the semantic:

Is "declare" here always only used as a declaration ? (e.g. only in
headers, never impacted by CREATE_TRACE_POINT ?)

Is "define" here always mapping to a definition ? (e.g. to be used in a
C file to define the class or event handling stub)

I feel that your DEFINE_EVENT_CLASS might actually be doing a bit more
than just "defining", it would actually also perform the declaration.
Same goes for "DEFINE_EVENT". So can you tell us a bit more about that
is the context of templates ?

Thanks,

Mathieu

> 
> -- Steve
> 
> 

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/