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Date: Thu, 15 Jan 2009 22:49:25 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
       Frederic Weisbecker <fweisbec@gmail.com>,
       Steven Rostedt <srostedt@redhat.com>
Subject: Re: [PATCH 1/6] ftrace: move function tracer functions out of
 trace.c
Message-Id: <20090115224925.6b0e6c24.akpm@linux-foundation.org>
In-Reply-To: <20090116045417.632296101@goodmis.org>
References: <20090116045342.748642160@goodmis.org>
	<20090116045417.632296101@goodmis.org>
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On Thu, 15 Jan 2009 23:53:43 -0500 Steven Rostedt <rostedt@goodmis.org> wrote:

>  static void
> +function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip)
> +{
> +	struct trace_array *tr = func_trace;
> +	struct trace_array_cpu *data;
> +	unsigned long flags;
> +	long disabled;
> +	int cpu, resched;
> +	int pc;
> +
> +	if (unlikely(!ftrace_function_enabled))
> +		return;

We're optimizing for the tracing-is-enabled case.  What's the thinking
here?