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From: "Frédéric Weisbecker" <fweisbec@gmail.com>
To: "Steven Rostedt" <rostedt@goodmis.org>
Cc: "Ingo Molnar" <mingo@elte.hu>,
	"Heiko Carstens" <heiko.carstens@de.ibm.com>,
	"Peter Zijlstra" <a.p.zijlstra@chello.nl>,
	linux-kernel@vger.kernel.org
Subject: Re: bug: ftrace & lockdep badness
Date: Wed, 5 Nov 2008 18:01:18 +0100	[thread overview]
Message-ID: <c62985530811050901w2feeee37r65af91657cfbd9b6@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.1.10.0811051143420.11900@gandalf.stny.rr.com>

2008/11/5 Steven Rostedt <rostedt@goodmis.org>:
> I do like the fact that lockdep checks it too. But there's times that we
> can not do that.
>
> Perhaps we can do something in between.
>
> Make a rb_spin_lock macro inside ring_buffer.c that can be either a
> spin_lock or a raw_spin_lock.  There are some tracers that must have this
> as a raw (function trace, irqsoff and preemptoff), but the rest should be
> fine. We can make it where the rb_spin_lock is a raw lock when any of
> those three tracers are configured, and make it into a normal lock when
> they are not.


But this way we won't be able to have lockdep checks when only one of
those "raw-need" tracers are
configured. Wouldn't it better to set it as a function pointer? It
would dynamically reference spin_lock or
raw_spin_lock functions depending on what tracer is currently
selected. I think that wouldn't hardly impact
the performances....

  reply	other threads:[~2008-11-05 17:01 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-05 12:37 Heiko Carstens
2008-11-05 13:07 ` Steven Rostedt
2008-11-05 16:04 ` Steven Rostedt
2008-11-05 16:30   ` Ingo Molnar
2008-11-05 16:47     ` Steven Rostedt
2008-11-05 17:01       ` Frédéric Weisbecker [this message]
2008-11-05 17:08       ` Ingo Molnar
2008-11-05 17:13         ` Steven Rostedt

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