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Date: Thu, 18 Dec 2014 16:10:20 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Jiri Olsa <jolsa@redhat.com>
Cc: mingo@kernel.org, linux-kernel@vger.kernel.org,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] perf ftrace: Factor regs retrieval for function tracer
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On Thu, Dec 18, 2014 at 03:28:27PM +0100, Jiri Olsa wrote:
> > Would not something like:
> > 
> > 	struct pt_regs *regs;
> > 
> > 	entry = perf_trace_buf_prepare(ENTRY_SIZE, TRACE_FN, &regs, &rctx);
> > 	if (!pt_regs) {
> > 		perf_fetch_caller_regs(regs);
> > 		pt_regs = regs;
> > 	}
> > 
> > Be simpler?
> 
> well, I wanted to omit touching the '__perf_regs' var
> in perf_trace_buf_prepare:
> 
>         if (regs)
>                 *regs = this_cpu_ptr(&__perf_regs[*rctxp]);

OK, fair enough I suppose. Thanks!