Re: [PATCH v3] ftrace: add a tracepoint for __raise_softirq_irqoff()

From: Steven Rostedt <rostedt@goodmis.org>
To: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>,
	linux-kernel@vger.kernel.org, mingo@elte.hu, fweisbec@gmail.com,
	zhaolei@cn.fujitsu.com, laijs@cn.fujitsu.com,
	Li Zefan <lizf@cn.fujitsu.com>
Subject: Re: [PATCH v3] ftrace: add a tracepoint for __raise_softirq_irqoff()
Date: Mon, 11 May 2009 10:09:04 -0400 (EDT)	[thread overview]
Message-ID: <alpine.DEB.2.00.0905111003280.14976@gandalf.stny.rr.com> (raw)
In-Reply-To: <20090511134019.GB10932@Krystal>

On Mon, 11 May 2009, Mathieu Desnoyers wrote:
> 
> Yes, we should try to fix TRACE_EVENT, but we should fix it _before_ we
> start using it widely. Circular header dependencies is a real problem
> with TRACE_EVENT right now.
> 
> Until we fix this, I will be tempted to stay with a known-good solution,
> which is DECLARE/DEFINE_TRACE.

The majority of tracepoints happen is C files. Those few cases where they 
are used in headers is where the issues arise.

But...

I did not want to uglify all trace event headers with:

#ifdef CREATE_FOO_TRACE_POINTS
#undef CREATE_FOO_TRACE_POINTS
#include <trace/define_trace.h>
#endif

We would only need to do that for those trace points that need to be 
included in header files. Then the declaration C file would need to define 
both CREATE_FOO_TRACE_POINTS and CREATE_TRACE_POINTS

#define CREATE_FOO_TRACE_POINTS
#define CRATE_TRACE_POINTS
#include <trace/events/foo.h>

But this is pretty trivial to solve, and I do not consider it a show 
stopper or a major header dependency problem.

-- Steve