From mboxrd@z Thu Jan  1 00:00:00 1970
From: Lars Ellenberg <lars.ellenberg@linbit.com>
Subject: Re: [Drbd-dev] [PATCH -next] drbd: trace depends on TRACING
Date: Wed, 30 Sep 2009 10:02:21 +0200
Message-ID: <20090930080221.GA8032@barkeeper1-xen.linbit>
References: <20090925133830.1ba29584.sfr@canb.auug.org.au> <4ABD4C28.9070202@oracle.com> <200909291732.51383.philipp.reisner@linbit.com> <20090929153747.GA29621@infradead.org>
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To: Christoph Hellwig <hch@infradead.org>
Cc: Philipp Reisner <philipp.reisner@linbit.com>, Randy Dunlap <randy.dunlap@oracle.com>, Stephen Rothwell <sfr@canb.auug.org.au>, LKML <linux-kernel@vger.kernel.org>, linux-next@vger.kernel.org, akpm <akpm@linux-foundation.org>, drbd-dev@lists.linbit.com
List-Id: linux-next.vger.kernel.org

On Tue, Sep 29, 2009 at 11:37:47AM -0400, Christoph Hellwig wrote:
> On Tue, Sep 29, 2009 at 05:32:50PM +0200, Philipp Reisner wrote:
> > On Saturday 26 September 2009 01:03:04 Randy Dunlap wrote:
> > > From: Randy Dunlap <randy.dunlap@oracle.com>
> > >
> > > DRBD_TRACE should depend on TRACING.
> > > It's also possible that TRACEPOINTS should depend on TRACING.
> > >
> >=20
> > Hi Randy,
> >=20
> > I tried to figure out in which way that should be done. By looking
> > at "BLK_DEV_IO_TRACE" I got the impression that this should
> > be done by adding "select GENERIC_TRACER".
>=20
> Neither really.  The only way of tracing that should be used is the
> TRACE_EVENT macros, which compile away to nothing if tracing is
> disabled, so no dependency is needed at all.

TRACE_EVENT macros depend on, and use TRACE_POINTS.
And those trace points are what compiles away if !CONFIG_TRACEPOINTS, n=
o?

kernel/trace/Kconfig says
# All tracer options should select GENERIC_TRACER. [...]

If one uses tracepoints without trace_events, they still compile away.

If using tracepoints directly, not using the (admittedly elegant)
trace-events macro system, is in fact not wanted anymore, then
Documentation/trace/* should be changed accordingly.

So what is the plan, going forward?

--=20
: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

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